Acoustic output device and method of controlling an acoustic output device

Abstract

An acoustic output apparatus according to the disclosure includes a housing (520), at least one outwardly directed microphone (100) disposed in the housing so as to be directed to an outside of the housing, and at least two drivers (140(1)-(L)) disposed inside the housing and generating acoustic control sounds based on acoustic control signals, respectively. Further, in a control method for an acoustic output apparatus according to the disclosure, a processor (300a) causes at least two drivers disposed inside a housing in which at least one microphone is disposed to be directed to an outside of the housing to generate acoustic control sounds based on acoustic control signals.

Description

Technical Field

[0001] This disclosure relates to an acoustic output device and a method for controlling the acoustic output device. Background Technology

[0002] A noise cancellation system is known in which a microphone for collecting external sound is housed within the housing of an acoustic output device (hereinafter appropriately referred to as a head-mounted acoustic output device) worn on the head or outer ear (such as headphones or earbuds), and signal processing is performed based on the sound collected by the microphone to remove sound (external noise) reaching the auricle from the outside. In this noise cancellation system, for example, external noise removal is achieved by adding a sound signal having a phase opposite to the sound signal collected by the microphone to the original sound signal output by the head-mounted acoustic output device.

[0003] Patent document 1 discloses an earphone in which a speaker array with multiple speakers disposed inside the earphone housing is installed inside the housing. This configuration improves sound image localization when listening to speech signals from both the L (left) and R (right) channels through the earphone.

[0004] Furthermore, Patent Document 2 discloses an earphone in which multiple microphones (referred to as FF microphones) for feedforward noise cancellation are mounted on the exterior of the earphone housing. In Patent Document 2, this configuration enables control to perform noise cancellation without eliminating external sounds or noise from a specific direction.

[0005] Reference List

[0006] Patent documents

[0007] Patent Document 1: JP 2012-178748 A

[0008] Patent Document 2: JP 2008-116782 A Summary of the Invention

[0009] Technical issues

[0010] Meanwhile, considering the scenarios for listening to music in recent years, the widespread use of portable music players and smartphones has led to many users listening to music outdoors with headphones. Given this situation, Patent Document 1 did not consider outdoor use, and there is a possibility that ambient noise leakage into the headphone housing could result in unclear sound image localization. Furthermore, while Patent Document 2 can eliminate external sounds from a specific direction, leakage of external sounds from directions other than that specific direction can still lead to unclear sound image localization.

[0011] The purpose of this disclosure is to provide an acoustic output device capable of outputting clearer reproduced sound and a method for controlling the acoustic output device.

[0012] Solution to the problem

[0013] To address the aforementioned problems, an acoustic output device according to one aspect of this disclosure comprises: a housing; one or more outward-facing microphones disposed on the housing facing outwards; and two or more drivers disposed inside the housing, each driver generating an acoustic control sound based on an acoustic control signal. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating the configuration of a noise cancellation headphone using a single microphone / single driver FF method based on the prior art and employing a transfer function.

[0015] Figure 2 This is a schematic diagram of a vertical cross-section illustrating the appearance of a noise-cancelling headset applicable to the single-microphone / multi-driver FF method of the first embodiment.

[0016] Figure 3A This is a schematic diagram illustrating an example configuration of an acoustic output device according to the first embodiment.

[0017] Figure 3B This is a functional block diagram illustrating an example of the function of the DSP according to the first embodiment.

[0018] Figure 4 This is a diagram showing the configuration of an acoustic output device according to the first embodiment using a transfer function.

[0019] Figure 5 This is a schematic diagram illustrating the effect of the acoustic output device according to the first embodiment.

[0020] Figure 6 This is a schematic diagram illustrating the effect of the acoustic output device according to the first embodiment.

[0021] Figure 7 This is a schematic diagram illustrating noise cancellation according to the prior art.

[0022] Figure 8 This is a schematic diagram illustrating noise cancellation of high sound pressure level noise according to the first embodiment.

[0023] Figure 9 This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a modified headphone applicable to the first embodiment.

[0024] Figure 10This is a schematic diagram illustrating an example of the frequency characteristics of the sound signal provided to each driver.

[0025] Figure 11 This is a schematic diagram illustrating an example of the characteristics of a full-range driver and a corresponding FFNC filter.

[0026] Figure 12 This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a noise cancellation headphone using the multi-microphone / multi-driver FF method according to the second embodiment.

[0027] Figure 13A This is a schematic diagram illustrating an example configuration of an acoustic output device according to a second embodiment.

[0028] Figure 13B This is a functional block diagram used to explain an example of the function of the DSP according to the second embodiment.

[0029] Figure 14 This is a diagram illustrating the configuration of an acoustic output device according to a second embodiment using a transfer function.

[0030] Figure 15 This is a schematic diagram illustrating the outline of noise cancellation according to the second embodiment.

[0031] Figure 16 This is a schematic diagram illustrating noise cancellation according to the prior art.

[0032] Figure 17 This is a diagram illustrating the configuration of a noise cancellation headset based on the existing single-microphone / single-driver FB method using a transfer function.

[0033] Figure 18 This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a noise cancellation headphone using the multi-microphone / multi-driver FB method according to a third embodiment.

[0034] Figure 19A This is a schematic diagram illustrating an example configuration of an acoustic output device according to a third embodiment.

[0035] Figure 19B This is a functional block diagram used to explain an example of the function of the DSP according to the third embodiment.

[0036] Figure 20 This is a diagram showing the configuration of an acoustic output device according to a third embodiment using a transfer function.

[0037] Figure 21 This is a diagram showing the configuration of an acoustic output device according to a third embodiment using a transfer function.

[0038] Figure 22 This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a multi-microphone / multi-driver dual-method noise cancellation headphone according to the fourth embodiment.

[0039] Figure 23A This is a schematic diagram illustrating an example configuration of an acoustic output device according to the fourth embodiment.

[0040] Figure 23B This is a functional block diagram used to explain an example of the function of the DSP according to the fourth embodiment.

[0041] Figure 24 This is a diagram showing the configuration of an acoustic output device according to the fourth embodiment using a transfer function.

[0042] Figure 25A This is a schematic diagram illustrating the reproduction of an object sound source according to the fifth embodiment.

[0043] Figure 25B This is a schematic diagram illustrating the state of moving the location of the reproduced sound when reproducing the target sound source according to the fifth embodiment.

[0044] Figure 26A This is a schematic diagram illustrating an example configuration of an acoustic output device according to the fifth embodiment.

[0045] Figure 26B This is a functional block diagram used to explain an example of the function of the DSP according to the fifth embodiment.

[0046] Figure 27 This is a diagram showing the configuration of an acoustic output device according to a fifth embodiment using a transfer function.

[0047] Figure 28A This is a schematic diagram illustrating an example configuration of an acoustic output device according to a variation of the fifth embodiment.

[0048] Figure 28B This is a functional block diagram illustrating an example of the function of the DSP according to a variation of the fifth embodiment.

[0049] Figure 29 This is a schematic diagram illustrating the reproduction control according to the sixth embodiment.

[0050] Figure 30A This is a schematic diagram illustrating an example configuration of an acoustic output device according to the sixth embodiment.

[0051] Figure 30B This is a functional block diagram used to explain an example of the function of the DSP according to the sixth embodiment.

[0052] Figure 31 This is a diagram illustrating the configuration of an acoustic output device according to the sixth embodiment using a transfer function.

[0053] Figure 32 This is a schematic diagram illustrating a voice call according to a modified example of the sixth embodiment.

[0054] Figure 33A This is a schematic diagram illustrating an example configuration of an acoustic output device according to a variation of the sixth embodiment.

[0055] Figure 33B This is a block diagram illustrating the configuration of an example of a DSP according to a variation of the sixth embodiment.

[0056] Figure 34 This is a schematic diagram illustrating an example of a method for measuring intraocular characteristics T according to the seventh embodiment.

[0057] Figure 35 This is a schematic diagram illustrating the configuration of an example of an acoustic output device according to the seventh embodiment.

[0058] Figure 36 This is a flowchart illustrating an example of the measurement process according to the seventh embodiment.

[0059] Figure 37 This is a schematic diagram illustrating the configuration of an example of an acoustic output device according to a first variation of the seventh embodiment.

[0060] Figure 38 This is a schematic diagram illustrating the configuration of an example of an acoustic output device according to a second variation of the seventh embodiment.

[0061] Figure 39 This is a flowchart illustrating an example of the correction value calculation process according to the second variation of the seventh embodiment.

[0062] Figure 40 This is a schematic diagram used to illustrate the wearing determination according to the third variation of the seventh embodiment.

[0063] Figure 41A The diagram illustrates an example of a notification method for informing a user of the status of wearing headphones according to the eighth embodiment.

[0064] Figure 41B This is a diagram illustrating an example of a notification method that informs a user of the conditions for wearing headphones applicable to the eighth embodiment.

[0065] Figure 42 This is a schematic diagram illustrating an example configuration of an acoustic output device according to the eighth embodiment.

[0066] Figure 43 This is a schematic diagram showing an example of a function setting screen displayed on a terminal device and applicable to the eighth embodiment.

[0067] Figure 44A This is a schematic diagram illustrating an example of a driver according to the ninth embodiment being used as a microphone.

[0068] Figure 44B This is a schematic diagram illustrating an example of a driver according to the ninth embodiment being used as a microphone.

[0069] Figure 45 This is a flowchart illustrating an example of a process for measuring intra-ear characteristics T using a driver as a microphone according to the ninth embodiment. Detailed Implementation

[0070] In the following description, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the embodiments described below, the same components are indicated by the same reference numerals, and therefore repeated descriptions will be omitted.

[0071] In the following text, embodiments of the present disclosure will be described in the following order.

[0072] 1. Overview of Implementation Examples

[0073] 2. First Embodiment

[0074] 2-1. Existing Technology

[0075] 2-2. Configuration according to the first embodiment

[0076] 2-3. Effects of the first embodiment

[0077] 2-4. Variations of the first embodiment

[0078] 3. Second Embodiment

[0079] 3-1. Configuration according to the second embodiment

[0080] 3-2. Effects according to the second embodiment

[0081] 4. Third embodiment

[0082] 4-1. Existing Technology

[0083] 4-2. Configuration according to the third embodiment

[0084] 5. Fourth Embodiment

[0085] 6. Fifth Embodiment

[0086] 6-1. Variations of the Fifth Embodiment

[0087] 7. Sixth Embodiment

[0088] 7-1. Variations of the Sixth Embodiment

[0089] 8. Seventh Embodiment

[0090] 8-1 First variation of the seventh embodiment

[0091] 8-2. Second variation of the seventh embodiment

[0092] 8-3. Third variation of the seventh embodiment

[0093] 9. Eighth Embodiment

[0094] 10. Ninth Embodiment

[0095] [1. Overview of the Implementation Examples]

[0096] First, an overview of embodiments of the present disclosure will be described. The present disclosure relates to an acoustic output device worn on the head and used by a user, and the acoustic output device applicable to the present disclosure includes over-ear (or on-ear) headphones (hereinafter, headphones) that provide sound generated when a diaphragm vibrates from near the listener's auricle according to an acoustic signal in a driver unit.

[0097] In the prior art, a type of headphone with noise cancellation functionality using a feedforward method (hereinafter, FF method) is known, wherein a microphone is disposed in the headphone housing facing outwards, and a signal for canceling noise leaking into the headphone from the outside is generated based on the sound collected by the microphone. Hereinafter, the headphone with noise cancellation functionality using the FF method is appropriately referred to as an FF method noise cancellation headphone.

[0098] In addition, headphones with noise cancellation functionality using a feedback method (hereinafter, the FB method) are also known, wherein a microphone is positioned toward the interior of the housing, and leakage noise entering the housing is cancelled based on the sound collected by the microphone; and headphones with noise cancellation functionality using a dual method combining the FF method and the FB method.

[0099] In the following text, headphones with noise cancellation functionality are appropriately referred to as noise-cancelling headphones. Furthermore, headphones with FF method noise cancellation functionality are referred to as FF method noise-cancelling headphones, headphones with FB method noise cancellation functionality are referred to as FB method noise-cancelling headphones, and headphones with dual method noise cancellation functionality are appropriately referred to as dual method noise-cancelling headphones. Additionally, microphones used to implement FF method noise cancellation functionality are appropriately referred to as FF microphones, and microphones used to implement FB method noise cancellation functionality are appropriately referred to as FB microphones.

[0100] In all existing FF method noise cancellation headphones, FB method noise cancellation headphones, and dual method noise cancellation headphones, only one drive unit (speaker) for generating noise cancellation sound based on the noise cancellation signal is provided in a housing.

[0101] The noise-canceling headphones, as an acoustic output device according to this disclosure, have the following structure, wherein multiple driver units are arranged in corresponding shells covering the user's left and right ear portions, each driver unit generating sound according to an audio signal. Hereinafter, the arrangement of multiple driver units in each of the left and right shells in this manner is referred to as multi-driver.

[0102] In the multi-driver noise-canceling headphones according to this disclosure, which serve as acoustic output devices, a plurality of driver units disposed in the housings each generate noise-canceling sounds based on sounds collected by microphones disposed in each housing. As described above, since the plurality of driver units are disposed in the acoustic output devices in each of the left and right housings, generating noise-canceling sounds from each of the plurality of driver units allows for a higher noise cancellation effect.

[0103] Note that the acoustic output device of this disclosure is essentially configured to generate a noise cancellation signal for performing noise cancellation by observing (collecting) ambient noise using an outward-facing FF microphone disposed in the housing of the headphones. Therefore, assuming one or more FF microphones are mounted on each of the left and right housings, the following modes can be conceived as corresponding modes.

[0104] (1) The first mode is a multi-driver noise cancellation headset, wherein an FF microphone is installed in each housing. In the following text, this configuration is appropriately referred to as a single-microphone / multi-driver FF method noise cancellation headset.

[0105] (2) The second mode is a multi-driver noise cancellation headset, in which two or more FF microphones are mounted in each housing. Hereinafter, this configuration is appropriately referred to as a multi-microphone / multi-driver FF method noise cancellation headset.

[0106] [2. First Implementation Method]

[0107] The first embodiment according to this disclosure will now be described.

[0108] (2-1. Prior Art)

[0109] First, for ease of understanding, noise cancellation using a single microphone / single driver FF method according to the prior art will be described. Figure 1This is a diagram illustrating the configuration of a noise cancellation headphone using a single microphone / single driver FF method based on the prior art and employing a transfer function.

[0110] exist Figure 1 In this design, the FF microphone 100 is an outward-facing microphone positioned facing the exterior of the earphone housing (not shown). For example, the FF microphone 100 is non-directional, positioned outside the earphone housing, and collects sound from outside the housing. The FF microphone 100 collects noise 20 with characteristics “N” generated outside the housing via a space 21 of spatial transfer function X. The sound signal output from the FF microphone 100 is provided to and amplified by the microphone amplifier 110. The transfer function of the FF microphone 100 and the microphone amplifier 110 is set to “M”. The output of the microphone amplifier 110 is passed to an FF noise cancellation (FFNC) filter 120 with a filter coefficient α for performing noise cancellation (NC) of the FF method.

[0111] FFNC filter 120 generates a noise cancellation signal based on the input signal to generate a noise cancellation sound. The noise cancellation signal generated by FFNC filter 120 is transmitted to drive amplifier 130 with transfer function A. Drive amplifier 130 drives driver 140 (described as driver 140 in the figure) with transfer function D according to the transmitted noise cancellation signal. Driver 140 generates noise cancellation sound by air vibration according to the noise cancellation signal. The noise cancellation sound is transmitted from driver 140 to control point (e.g., the eardrum of a user wearing headphones) via space 23 of spatial transfer function G.

[0112] Here, the noise cancellation sound can be considered as the acoustic control sound used to control the audio in the housing (space 23) of the headphones, and the noise cancellation signal is the acoustic control signal used by the driver 140 to reproduce the acoustic control sound.

[0113] In the following description, unless otherwise specified, drive 140 will be described as drive 140.

[0114] On the other hand, noise 20 propagates through space 22 of the space transfer function F and leaks into the earphone via the earphone housing. The noise 20 leaking into the earphone is added as an additive unit 160 to the noise cancellation sound generated by the driver 140 in the space within the housing, and the noise 20 is canceled. The sound canceled by the noise cancellation sound reaches the user's eardrum as a sound pressure (p) 150.

[0115] At this time, in the FFNC filter 120, it is only required that the sound pressure (p) at the eardrum position is "0", and the filter coefficient α can be obtained by the following expression (1).

[0116] p=NF+NXMαADG=0 (1)

[0117] When solving expression (1) for the filter coefficient α, the following expression (2) is obtained.

[0118] p=NF+NXMαADG=0 (1)

[0119]

[0120] By determining the filtering coefficients of the FFNC filter 120 in this way, the user wearing the headphones can hear the sound of noise 20 generated outside the headphone housing being eliminated.

[0121] (2-2. Configuration according to the first embodiment)

[0122] Next, a configuration according to a first embodiment of this disclosure will be described. The first embodiment relates to the noise cancellation headphones using the single microphone / multi-driver FF method described above.

[0123] Figure 2 This is a schematic vertical cross-sectional view illustrating the appearance of an example of a single-microphone / multi-driver FF method noise cancellation headset 50 applicable to the first embodiment. In the following text, "single-microphone / multi-driver FF method noise cancellation headset 50" will be simply referred to as "headset 50". It should be noted that... Figure 2 The left and right shells of the earphone 50 are shown.

[0124] exist Figure 2 In this example, the housing 520 of the earphone 50 is connected to the opposite housing 520 (on the right side of the figure) via a headband (not shown). Furthermore, ear pads 510 are provided on the outer periphery of the housing 520, and the ear pads 510 of the left and right housings 520 press against the head 40 of the user wearing the earphone 50.

[0125] L drivers 1401, 1402, ..., 140 are installed inside the housing 520. L .exist Figure 2 In this example, assuming L=3, there are three drives: 1401, 1402, and 140... L It is mounted on housing 520. For example, L drivers 1401, 1402, ..., and 140 L Arranged on the housing 520, the emitted sound waves propagate in different directions.

[0126] exist Figure 2 In the example, when the user wears headphones 50 in a normal state, drivers 1401, 1402, and 140... LIt is shown as being positioned in a substantially vertical direction, but this is not limited to this example. For example, drives 1401, 1402, and 140... L It can be arranged horizontally or diagonally, or it can be placed at the corresponding vertices of a triangle.

[0127] exist Figure 2 In these examples, driver 1401 is positioned and oriented such that the emitted sound (air vibration) can be transmitted directly to the user's eardrum 61 via the ear canal 60. In other words, driver 1401 is arranged in the generally central portion inside the housing 520 so that it can output sound in the direction of the eardrum 61.

[0128] Drives 1402 and 140 L Each of the actuators is positioned from the center portion of the housing 520 toward the peripheral portion. More specifically, the actuator 1402 is disposed on the upper part of the housing 520 in an inclined direction relative to the ear canal 60. Actuator 140 L It is arranged facing upwards at the lower part of the housing 520.

[0129] Furthermore, the FF microphone 100 is positioned on the external portion of the housing 520 of the earphone 50. Figure 2 In one example, the FF microphone 100 is positioned facing the driver 1401 via the housing 520, with the sound collection unit facing the outside of the housing 520.

[0130] Note that in Figure 2 In this embodiment, the driver 1401 is arranged on the housing 520 such that the output sound (sound wave) propagates with a wavefront substantially perpendicular to the eardrum 61; however, the arrangement of the driver 1401 on the housing 520 is not limited to this example. For instance, the driver 1401 may be arranged on the housing 520 such that the output sound wavefront propagates with a wavefront inclined relative to the direction of the eardrum 61 schematically shown by the ear canal 60 and eardrum 61 in the figure. Furthermore, for example, in... Figure 2 In this configuration, the driver 1401 is positioned on the axis of the eardrum 61 and ear canal 60, as schematically shown; however, the driver 1401 may be positioned offset from the axis of the housing 520. Furthermore, it is conceivable to arrange the driver 1401 on the outer periphery of the housing 520. The position of the FF microphone 100 is not limited to a position facing the driver 1401 via the housing 520.

[0131] Figure 3A This is a schematic diagram illustrating an example configuration of the acoustic output device according to the first embodiment. Figure 3A In the example, the acoustic output device includes headphones 50, a microphone amplifier 110, and driver amplifiers 1301, 1302, ..., and 130... LThe system includes an ADC 200, a DAC 201, a memory 210, an operation unit 211, and a DSP 300a. An operator for receiving user operations is located in the operation unit 211. The DSP 300a executes control according to the user operations on the operation unit 211 based on the program.

[0132] exist Figure 3A In the middle, due to the configuration of the headphones 50 and in Figure 2 The configuration is the same as in the previous one, so its description is omitted here. The headphone 50 includes three drivers: 1401, 1402, and 140. L In this example, the headphones have drivers 1401, 1402, and 140 respectively. L The corresponding three driver amplifiers are 1301, 1302 and 130 L .

[0133] The analog-to-digital converter (ADC) 200 converts the analog sound signal collected through the FF microphone into a digital sound signal. The digital signal processor (DSP) 300a receives the sound signal converted into a digital signal by the ADC 200 and the audio signal 700 primarily listened to using headphones 50.

[0134] exist Figure 3A In the accompanying figures, the symbol “ / (slash)” or “\ (backslash)” attached to a signal line indicates that the signal line includes multiple signal lines or transmits signals for multiple channels.

[0135] Figure 3B This is a functional block diagram illustrating an example of the functionality of the DSP 300a according to the first embodiment. Figure 3B In this DSP 300a, there are control unit 310, equalizer (EQ) 311, level control unit 312, adder 313, FFNC filter 320a, and cancellation control unit 321. FF .

[0136] The control unit 310, EQ 311, level control unit 312, adder 313, FFNC filter 320a, and cancellation control unit 321 are implemented by executing an acoustic output control program on the DSP 300a. FF Not limited to this, control unit 310, EQ 311, level control unit 312, adder 313, FFNC filter 320a and elimination control unit 321 are also included. FF Some or all of them can be configured using hardware circuits that work together with each other.

[0137] For example, when executing the acoustic output control program, the DSP 300a will control the control unit 310, EQ 311, level control unit 312, adder 313, FFNC filter 320a, and cancellation control unit 321. FF The module is configured, for example, to be included in a memory region (not shown) that serves as the main storage area in the DSP 300a. Note that the acoustic output control program is pre-stored in, for example, memory 210, and enters an executable state by being read from memory 210 by the DSP 300a upon activation. Furthermore, the acoustic output control program can be provided externally via a communication device (not shown) and stored in memory 210, etc.

[0138] In the DSP 300a, the control unit 310 controls each unit of the DSP 300a according to a program stored, for example, in the memory 210. Furthermore, the control unit 310 controls each unit of the DSP 300a according to a program based on operations on the operation unit 211.

[0139] An externally input audio signal 700 is provided to EQ 311 for EQ processing, and its level (volume) is adjusted in the level control unit 312. The audio signal 700, whose level has been adjusted by the level control unit 312, is then passed to adder 313. Note that various parameters in EQ 311 and level control unit 312 can be changed, for example, by control unit 310 according to user operation on operating unit 211.

[0140] The audio signal provided by the ADC 200 is input to an FFNC filter 320a with a filtering coefficient α. The FFNC filter 320a has L drivers 1401, 1402, ..., 140... L The corresponding L FFNC drivers, through processing described later, generate 1401, 1402, ..., 140 based on the input audio signal. L The noise cancellation signal. The level of each noise cancellation signal generated by the FFNC filter 320a is controlled by the cancellation amount control unit 321. FF Adjust and pass the adjustment to adder 313.

[0141] Note the FFNC filter 320a and the cancellation control unit 321. FFThe parameters can be changed, for example, by control of control unit 310 based on user operation on operation unit 211. For example, control unit 310 can switch FFNC filter 320a to an FFNC filter with different characteristics based on user operation. As an example, control unit 310 can switch the default FFNC filter 320a to an FFNC filter whose parameters are optimized for a specific noise (such as aircraft noise) based on user operation. In addition, control unit 310 can control the cancellation amount control unit 321 based on user operation. FF The parameters are used to adjust the amount of noise cancellation signal that cancels noise 20.

[0142] Adder 313 synthesizes the audio signal 700 transmitted from level control unit 312 and from elimination control unit 321 to output the audio signal 700 transmitted from level control unit 312 and the audio signal 700 transmitted from elimination control unit 321. FF The transmission is with drivers 1401, 1402, ..., and 140 L Each corresponding noise cancellation signal in the DSP 300a is an acoustic signal obtained by adding the audio signal 700 to a signal used to cancel noise components generated outside the housing 520.

[0143] As described above, the DSP 300a is used as a signal processing unit to generate noise cancellation signals as acoustic control signals.

[0144] return Figure 3A As described, each acoustic signal output from the DSP 300a is passed to a digital-to-analog converter (DAC) 201, where the digital acoustic signal is converted into an analog acoustic signal. The acoustic signal converted to analog format by the DAC 201 is then provided to drive amplifiers 1301, 1302, and 130... L Driver amplifiers 1301, 1302 and 130 L Based on the provided acoustic signals, drivers 1401, 1402, and 140 are driven respectively. L .

[0145] Therefore, with the noise 20 generated outside the housing 520 of the headphones 50 suppressed, the user wearing the headphones 50 can listen to sound based on the audio signal 700.

[0146] Figure 4 This is a diagram illustrating the configuration of the acoustic output device according to the first embodiment using a transfer function. It should be noted that... Figure 4 One of the left and right configurations of the headset 50 is shown. Figure 4 The configuration shown is as follows: via multiple drives 1401, 1402, ..., and 140 L Parallel connection according to Figure 1The configuration of the FFNC filter 120, drive amplifier 130, driver 140, and space 23 in the prior art configuration shown is illustrated.

[0147] exist Figure 4 In the middle, FFNC filters 1201, 1202, ... and 120 L Depend on Figure 3B The FFNC filter 320a is implemented in the code, and the filter coefficients are α1, α2, ... and α... L Furthermore, drive amplifier 1301 and driver 1401, drive amplifier 1302 and driver 1402, ..., and drive amplifier 130 L and drive 140 L The transfer functions are respectively set as transfer functions A1 and D1, transfer functions A2 and D2, ..., and transfer function A L and D L In addition, spaces 231, 232, ... and 23 L These are the spatial transfer functions G1, G2, ... and G... L .

[0148] That is, in Figure 4 In the diagram, the configuration of FFNC filter 1201, driver amplifier 1301, driver 1401, and space 231 is for generating the canceled sound produced by driver 1401. Similarly, the connection structure of FFNC filter 1202, driver amplifier 1302, driver 1402, and space 232 is for generating the canceled sound produced by driver 1402. Furthermore, FFNC filter 120... L 130 drive amplifier L 140 drive L and Space 23 L The connection configuration is used to generate a connection from driver 140. L The generated sound cancellation configuration.

[0149] The sound signal collected by the FF microphone is transmitted from the microphone amplifier 110 to the FFNC filters 1201, 1202, ..., 120. L The sound signal is transmitted to the driver 1401 via, for example, an FFNC filter 1201 and a driver amplifier 1301 to generate noise-canceling sound, and the generated noise-canceling sound is input to the adder unit 160 via the space 231 within the housing 520.

[0150] Similarly, it is sent to FFNC filters 1202, ..., and 120 L The audio signals are respectively driven by amplifiers 1302, ..., and 130 LSent to drives 1402, ..., and 140 L To respectively become noise cancellation sound, and via spaces 232, ..., and 23 L The input is fed into the addition unit 160. Within the space of the housing 520, the addition unit 160 will pass through spaces 231, 232, ... and 23... L Each noise-cancelled sound input is added to the noise 20 input through space 22 to the outer housing 520 of the adder unit 160 to output them. The output of the adder unit 160 reaches the eardrum 61 of the user wearing the headphones 50 as sound pressure 150 (sound pressure (p)).

[0151] from Figure 4 If it is possible to eliminate the leakage noise (NF) at the position of eardrum 61, it is sufficient. Therefore, by using the sound pressure (p) = 0 at eardrum 61, the following expression (3) is obtained by extending the above expression (1) to parallel processing.

[0152]

[0153] Expression (4) is obtained by modifying expression (3).

[0154]

[0155] By obtaining the filter coefficients α1, α2, ..., α that satisfy expression (4), L As FFNC filters 1201, 1202, ... and 120 L Each of the filter coefficients α, when using an FF microphone and L drivers 1401, 1402, ..., 140 L Noise cancellation is possible under certain conditions.

[0156] (2-3. Effects based on the first embodiment)

[0157] The effects according to the first embodiment will then be described. In the first embodiment, by using multiple drivers 1401, 1402, ..., and 140... L Mounted on the housing 520 of the earphone 50, according to reference Figure 1 Compared to existing single-microphone / single-driver FF noise cancellation headphones, the described technology can improve noise cancellation performance.

[0158] In the following text, multiple drives 1401, 1402, ..., and 140... L Any drive in it is called drive 140 x In multiple FFNC filters 1201, 1202, ..., 120 L In the middle, with drive 140 xThe corresponding FFNC filter is set to have a filter coefficient α x FFNC filter 120 x .

[0159] There are three reasons for this: Compared to the configuration using a single driver 140 according to the prior art, the first embodiment provides multiple drivers 1401, 1402, ..., 140 in the housing 520. L The configuration can improve noise cancellation performance.

[0160] (1) FFNC filter 120 x Filter coefficient α x The degrees of freedom are higher than those of the filter coefficients of the existing FFNC filter 120. As a result, it is possible to generate and reproduce noise-cancelled signals with high precision.

[0161] (2) It can be driven from multiple drives 1401, 1402, ... and 140 L The driver 140 is located at the position of the approach noise 20 in the direction of entry. x Reproduce the noise-cancelled signal.

[0162] (3) Even under high sound pressure noise conditions, the noise cancellation signal can be reproduced with high accuracy.

[0163] (Noise entry direction)

[0164] Reference Figure 5 and Figure 6 Describe the reasons (1) and (2). Figure 5 and Figure 6 This is a schematic diagram illustrating the effect of the acoustic output device according to the first embodiment.

[0165] Figure 5 The noise 20 is shown to originate from the horizontal direction relative to the housing 520 (i.e., from the direction parallel to the direction facing the FF microphone and driver 1401).

[0166] Figure 5 Part (a) schematically shows the wavefront 400 of the noise 20 reaching the FF microphone disposed in the housing 520, and the wavefront 401 of the noise 20 leaking from the gap between the ear pad 510 disposed in the housing 520 and the head 40 of the user wearing the headphones 50. The noise 20 reaches the FF microphone via the space transfer function X, leaks into the interior of the housing 520 via the space transfer function F from the gap between the ear pad 510 and the head 40, and reaches the eardrum 61 via the ear canal 60, as shown by paths A and A'.

[0167] Figure 5Part (b) schematically illustrates an example of a wavefront of a noise-cancelled sound generated by reproducing noise 20 collected by an FF microphone and emitted from drivers 1401, 1402, and 1403 in housing 520. L The noise cancellation signal is obtained from each output of drivers 1401, 1402, and 140... L The noise-cancelling sounds indicated by the output wavefronts 402, 403, and 404 are synthesized at the entrance of the ear canal 60 and reach the eardrum 61 as the sound indicated by wavefront 405. Ideally, the sound indicated by wavefront 405 is, for example, a sound with a phase opposite to that of wavefront 401 caused by the leakage noise indicated in part (a).

[0168] Figure 5 Part (c) schematically shows Figure 5 The state of combining parts (a) and (b). Specifically, in Figure 5 In part (c), it is schematically shown that drives 1401, 1402 and 140 are used. L The sound represented by each reproduced sound and synthesized at the entrance of the ear canal 60, and the sound represented by the wavefront 401 of the noise 20 leaking from the gap between the ear pad 510 and the head 40, are synthesized and reach the state of the eardrum 61.

[0169] Since the wavefront 401 of the leakage noise and the wavefront 405 of the noise-cancelling sound are essentially matched, the leakage noise is eliminated by the noise-cancelling sound. Therefore, a user wearing headphones 50 can hear the sound in which the leakage noise is suppressed by the noise-cancelling sound.

[0170] Figure 6 The noise 20 is shown to originate from a direction perpendicular to the housing 520 (i.e., a direction perpendicular to the direction in which the FF microphone and driver 1401 face). Figure 6 In the example, the case of the upper side).

[0171] Figure 6 Part (a) schematically shows the wavefront 406 of the noise 20 reaching the FF microphone disposed in the housing 520, and the wavefront 407 of the noise 20 leaking from the gap between the ear pad 510 disposed in the housing 520 and the head 40 of the user wearing the headphones 50. The noise 20 reaches the FF microphone via path B in space via spatial transfer function X, and leaks into the housing 520 from the gap on the upper side of the housing 520 between the ear pad 510 and the head 40 via spatial transfer function F.

[0172] Figure 6Part (b) schematically illustrates an example of the wavefront of a noise-cancelling sound, wherein a noise-cancelling signal generated based on noise 20 collected by an FF microphone is driven by drivers 1401, 1402, and 140... L Each of them is reproduced, and from the drives 1401, 1402 and 140 in housing 520. L Each output in the process.

[0173] In this example, noise 20 originates from above the earphone 50, and the noise cancellation signal originates from three drivers 1402, 1402, and 1402 located on the housing 520. L The driver 1401, located in the upper part of the housing 520 (close to the arrival position of the noise 20), actively reproduces the noise.

[0174] As a more specific example, such as Figure 6 As shown in part (b), corresponding to drives 1401, 1402 and 140 L A high-level noise cancellation signal is generated in the driver amplifier 1302 of the driver 1402 located in the upper part of the housing 520. The driver 1402 reproduces the noise-cancelled sound based on the high-level noise cancellation signal. The noise-cancelled sound propagates toward the entrance of the ear canal 60, for example, as shown by wavefront 409.

[0175] For the driver 1401 located in the central portion of the housing 520, the corresponding drive amplifier 1301 generates a noise cancellation signal having a lower level (medium level) than the noise cancellation signal generated by the drive amplifier 1302 described above. The driver 1401 reproduces the noise-cancelled sound based on the medium-level noise cancellation signal. The noise-cancelled sound propagates toward the entrance of the ear canal 60, for example, as indicated by the wavefront 410.

[0176] Furthermore, for the driver 140 located at the lower part of the housing 520 L With drive amplifier 130 L Corresponding driver 140 L A noise cancellation signal with a lower level (low level) than the noise cancellation signal generated by the drive amplifier 1301 described above is generated. Driver 140 L The noise-cancelled sound is reproduced based on the low-level noise cancellation signal. In the example in this figure, the noise cancellation sound is not reproduced from driver 140. L Reproduce noise and eliminate sound.

[0177] Drives 1401, 1402 and 140 LThe reproduced noise-cancelling sounds are synthesized within the housing 520, and as shown by wavefront 408 in the figure, the synthesized noise-cancelling sounds are generated from top to bottom within the housing 520. Ideally, the sound indicated by wavefront 408 of the synthesized noise-cancelling sound is, for example, a sound with a phase opposite to that of wavefront 407 caused by the leakage noise shown in section (a).

[0178] Figure 6 Part (c) schematically shows the... Figure 6 The state of adding parts (a) and (b) in the above. Specifically, the synthesis is achieved by the synthesis in part (b) by drivers 1401, 1402, and 140. L The synthesized sound is obtained by reproducing noise-eliminating sound, with wavefront 408 indicating the sound, and leakage noise indicated by wavefront 407 due to noise 20 leaking from the gap between the upper side of the ear pad 510 and the head 40 in the housing 520. The synthesized sound reaches the eardrum 61.

[0179] Since the wavefront 407 of the leakage noise and the wavefront 408 of the sound obtained by synthesizing the respective noise-cancelling sounds are essentially matched, the leakage noise is canceled by the noise-cancelling sound (wavefront 407'). The sound represented by wavefront 407' is the sound in which the leakage noise is canceled by the noise-cancelling sound, and the user wearing headphones 50 can hear the sound in which the leakage noise from above is suppressed.

[0180] As described above, according to the configuration of the first embodiment, in addition to the driver 1401 located in the central portion of the housing 520 of the earphone 50, for example, the driver 1402 is mounted in the upper part of the housing 520. Therefore, even when the noise 20 arrives from above the earphone 50, noise cancellation corresponding to the direction of noise 20's arrival can be performed by actively reproducing the noise cancellation signal in the driver 1402, which is positioned close to the direction of noise 20's arrival. Therefore, the reproduced sound by the earphone 50 can be made clearer.

[0181] It should be noted that, in addition to the FF microphones located in the left and right housings 520 of the earphone 50, the direction of arrival of the microphone facing the upper side of the earphone 50 and the noise 20 to the earphone 50 can also be estimated based on the sound collected by, for example, the left and right FF microphones and the microphone facing upward. This is not limited to, for example, FFNC filters 1201, 1202, ..., and 120... L And drive amplifiers 1301, 1302, ... and 130 L Each of the settings can be switched to a setting corresponding to the noise 20 from above, based on the operation of the operation unit 211 and the control of the control unit 310.

[0182] Figure 7 This is a schematic diagram illustrating noise cancellation using a single-microphone / single-driver noise cancellation headset according to the prior art. Figure 7 In the earphone 51 shown in parts (a) and (b), only one driver 140 is provided on the central portion of the housing 520. Furthermore, an FF microphone is positioned facing the driver 140 through the housing 520. Figure 1 The configuration described by the transfer function in the document is applied to the configuration of the headphone 51.

[0183] Figure 7 Part (a) shows the situation where noise 20 reaches housing 520 from the horizontal direction. Figure 5 Similar to part (a), noise 20 leaks from the gap between the ear pad 510 of the housing 520 and the head 40, as shown by paths A and A', and reaches the eardrum 61 via the ear canal 60 as leakage noise. In this configuration, the noise 20 indicated by the wavefront 400 is collected by the FF microphone, and the noise cancellation signal generated based on the collected noise 20 is reproduced as noise-cancelled sound by the driver 140. The noise-cancelled sound and the leakage noise are synthesized in the space within the housing 520 and reach the eardrum 61 via the ear canal 60. Therefore, as in use Figure 5 In the description of parts (a) to (c), the user can listen to the sound of the leakage noise being suppressed by the noise cancellation sound.

[0184] Figure 7 Part (b) shows the noise 20 from the reference. Figure 6 The case described is where the sound reaches the housing in the vertical direction. In this case, the earphone 51 does not include a driver located on the upper part of the housing 520. Therefore, as shown by wavefront 402, the sound arriving from the horizontal direction toward the ear canal 60 is eliminated, and the leakage noise arriving from above the housing 520, represented by wavefront 407, is difficult to eliminate.

[0185] As described above, in the case of a single microphone / single driver, good noise cancellation can be performed on noise 20 arriving from the direction where driver 140 is located, but there is a possibility that sufficient noise cancellation performance cannot be obtained for noise 20 arriving from other directions.

[0186] (Coping with high sound pressure level noise)

[0187] Next, the reason (3) mentioned above will be described by setting multiple drives 1401, 1402, ..., 140 L To handle high sound pressure level noise.

[0188] As described above, by using multiple drives 1401, 1402, ..., 140 LThe FFNC filter 120 is mounted on the housing 520, compared to the case where only one FFNC filter 120 is mounted. x The degrees of freedom increase. With the increased degrees of freedom of the FFNC filter 120x, it is possible to control multiple drivers 1401, 1402, ..., 140... L The noise cancellation signal used for noise cancellation 20 is reproduced, for example, noise cancellation can be performed even for high sound pressure noise with very high sound pressure.

[0189] Figure 8 This is a schematic diagram illustrating noise cancellation of high sound pressure level noise according to the first embodiment. Figure 8 Part (a) is a schematic diagram illustrating the elimination of high sound pressure level noise using a noise cancellation headphone employing a single-microphone / single-driver FF method according to the prior art. In the figure, the headphone 51 is compared with a reference... Figure 7 The described headphones 51 are identical, except that only one driver 140 is located in the central portion of the housing 520, and the FF microphone is located at a position facing the driver 140 via the housing 520.

[0190] As shown in path D, high sound pressure level noise 20 is collected via an FF microphone. BIG An FFNC filter 120 with filtering coefficient α is based on high sound pressure level noise 20 collected by an FF microphone. BIG Generate 20 for eliminating high sound pressure level noise BIG The noise cancellation signal is generated and provided to the driver 140 via a drive amplifier 130 (not shown). The driver 140 is based on the high sound pressure level noise 20 BIG The generated noise-cancelled signal is used to reproduce the noise-cancelled sound.

[0191] On the other hand, high sound pressure noise 20 BIG Leakage noise occurs along path E from the gap between the ear pad 510 and the head 40 into the housing 520. Here, it is assumed that the maximum sound pressure level that can be driven by the driver 140 is 80 dB sound pressure level (dBSPL), and the sound pressure level of the leakage noise at the location of the eardrum 61 is 100 dBSPL. In the prior art, because only one driver 140 is provided on the housing 520, noise cancellation can only be performed up to 80 dBSPL, and 20 dBSPL of leakage noise cannot be eliminated at the eardrum 61, which is the cancellation point.

[0192] Figure 8 Part (b) is used to illustrate the arrangement of a plurality of (three in this example) actuators 1401, 1402 and 140 on the housing 520 according to the first embodiment. L High sound pressure level noise 20 BIGA schematic diagram of noise cancellation.

[0193] High sound pressure level noise 20 collected by FF microphone BIG And transmit them respectively to the filters with filtering coefficients α1, α2, ..., α L FFNC filters 1201, 1202, ... and 120 L As shown in path D. FFNC filters 1201, 1202, ..., and 120 L Each of the 20 is based on the high sound pressure level noise transmitted from the FF microphone. BIG Generate 20 for eliminating high sound pressure level noise BIG The noise cancellation signal. FFNC filters 1201, 1202, ..., and 120 L The generated noise cancellation signals are respectively driven by amplifiers 1301, 1302, ..., and 130 L (Not shown) Provided to drives 1401, 1402, ..., and 140 L Drives 1401, 1402, ..., 140 L Each based on high sound pressure level noise 20 BIG The generated noise-cancelled signal is used to reproduce the noise-cancelled sound.

[0194] In this case, the sound pressure level corresponding to 100 [dBSPL] to be eliminated by the cancellation signal is controlled by multiple drivers 1401, 1402 and 140 L Dispersion and reproduction.

[0195] exist Figure 8 In part (b) of the example, driver 1401 reproduces a canceled sound of 50 [dBSPL], driver 1402 reproduces a canceled sound of 30 [dBSPL], and driver 140... L Reproduces 20 [dBSPL] of canceled sound, made possible by three drivers 1401, 1402 and 140 L The total sound pressure level of the reproduced canceled sound is set to 100 [dBSPL].

[0196] For example, control unit 310 controls FFNC filters 1201, 1202 and 120 L The filter coefficients α1, α2, and α L Each is set to a predetermined setting, thus enabling operation on each drive 1401, 1402, and 140. L The noise-cancelled sound with the desired sound pressure level is reproduced. Alternatively, the control unit 310 can control the drive amplifiers 1301, 1302, and 130... L Each of them enables drives 1401, 1402, and 140 LEach reproduction in the noise-removing sound has the desired sound pressure level.

[0197] As described above, in the first embodiment, high sound pressure level noise 20 can also be easily handled. BIG Noise cancellation. As an example, by applying noise cancellation according to the first embodiment, the hearing of DJs (Disc Jockeys) performing at high sound pressure levels, such as club music, and workers working in noisy environments can be protected.

[0198] (2-4. Variations of the first embodiment)

[0199] Next, a variation of the first embodiment will be described. A variation of the first embodiment is a plurality of actuators 1401, 1402, ..., and 1403 arranged in the housing 520. L Each of them is not used as a full-range driver, but rather as an instance of a driver that reproduces the sound signal of each frequency band obtained by dividing the reproduction frequency band.

[0200] Figure 9 This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a modified headphone applicable to the first embodiment. Figure 9 The headset 52 includes an FF microphone and three 140 drivers. tw 140 wf and 140 mid Drive 140 tw The tweeter is responsible for high-frequency reproduction, and the driver 140 is a mid-range driver responsible for mid-frequency reproduction. wf It is a woofer that performs low-frequency reproduction.

[0201] For example, in Figure 3A In the configuration shown, the audio signal output from DAC 201 is filtered into high-frequency, mid-frequency, and low-frequency audio signals through a predetermined speaker network and supplied to driver 140. tw 140 mid and 140 wf . Figure 10 This is an illustrative representation of the drive 140. tw 140 mid and 140 wf A diagram illustrating an example of the frequency characteristics of an audio signal. Supply to driver 140 tw The audio signal tw is obtained by cutting a frequency band below the first frequency and is supplied to the driver 140. wf The audio signal wf is obtained by cutting a frequency band higher than the second frequency and lower than the first frequency. Furthermore, it is provided to the driver 140. midThe sound signal mid is obtained by cutting a frequency band higher than the first frequency and a frequency band lower than the second frequency.

[0202] As described above, by limiting the supply to multiple drives 140 tw 140 mid and 140 wf Each audio signal's frequency band, compared to the case of using a full-range driver, does not exhibit unwanted peaks / notches in its frequency characteristics, thus enabling stable reproduction of the canceled signal.

[0203] Next, a comparison with existing technologies will be described using multiple drivers 140. tw 140 mid and 140 wf The frequency band division can stably reproduce the points where the signal has been eliminated. Using... Figure 1 The transfer function described in the text describes the configuration of noise cancellation using the single-microphone / single-driver FF method according to the prior art, and the filtering coefficient α of the FFNC filter 120 is obtained through the above expressions (1) and (2). At this time, as can be seen from expression (2), the transfer function D of the driver 140 exists on the denominator side.

[0204] Here, the characteristics of the FFNC filter 120 when using only a full-range driver will be considered. Figure 11 This is a schematic diagram illustrating an example of the characteristics of a full-range driver and a corresponding FFNC filter. Figure 11 In parts (a) and (b), the vertical axis represents power [dB] and the horizontal axis represents frequency.

[0205] For example, suppose we have as follows Figure 11 The frequency characteristics of the full-range driver 140 are shown in part (a). Almost no full-range driver has a flat characteristic from low to high frequencies. Figure 11 In example (a), the driver characteristic (D) is the characteristic that the power rises at the mid-frequency and drops sharply in a predetermined frequency band (HR) at the high frequency. In this figure, the driver characteristic is shown as a transfer function (D).

[0206] Figure 11 Part (b) shows the relationship with Figure 11The characteristics of the FFNC filter 120 corresponding to the characteristics in part (a) are shown in the figure. The characteristics of the FFNC filter are shown as the filter coefficients α. According to the above expression (2), since the driver characteristic (D) exists on the denominator side, the characteristics of the FFNC filter 120 have a rough shape that approximates the inverse of the driver characteristic (D) shown in part (a), as shown in part (b). In the example in this figure, the power increases sharply in the frequency band HR where the power decreases sharply in the driver characteristic (D).

[0207] exist Figure 11 In the case of the driver characteristics (D) shown in part (a), the FFNC filter 120 has high power in the HR band, although the driver 140 has difficulty reproducing high-frequency (i.e., HR band) sounds. Therefore, the driver 140 attempts to forcibly reproduce the noise-cancelled signal based on the output of the FFNC filter 120. As a result, the reproduced noise-cancelled signal is distorted, and the noise is amplified instead of being eliminated.

[0208] As a countermeasure, noise cancellation signal distortion can be prevented by cutting off the power of the high-frequency components of the FFNC filter 120. However, in this case, it is difficult to cancel noise in the high frequency range because the power is cut off. Therefore, by using multiple drivers, with each driver performing frequency band division and generating a cancellation signal for each divided frequency band, noise in the broadband from low frequency to high frequency can be eliminated.

[0209] [3. Second Implementation]

[0210] Next, a second embodiment of the present disclosure will be described. The second embodiment is an example in which the present disclosure is applied to a noise cancellation headphone using a multi-microphone / multi-driver FF method, wherein two or more drivers are disposed inside the headphone housing and two or more FF microphones are positioned facing outwards from the housing.

[0211] (3-1. Configuration according to the second embodiment)

[0212] Figure 12 This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a multi-microphone / multi-driver FF method noise cancellation headset 53 according to the second embodiment. Hereinafter, "multi-microphone / multi-driver FF method noise cancellation headset 53" will be simply referred to as "headset 53". It should be noted that... Figure 12 The left and right housings of the earphone 53 are shown, with the right housing 520 being the right housing.

[0213] exist Figure 12 In the earphone 53 shown, there are L drivers 1401, 1402, ..., and 140... L Set within housing 520, with reference Figure 2 The headphones described are the same as those in model 50. Figure 12 In this example, assuming L=3, there are three drives: 1401, 1402, and 140... L Mounted on housing 520. Drivers 1401, 1402, and 140 L The alignment direction is not limited to Figure 12 The vertical direction shown in the figure can be either horizontal or inclined.

[0214] The earphone 53 has J FF microphones 1001, 1002, ..., and 100 on its housing 520, facing outwards from the housing 520. J In the example shown, the three drives are 1401, 1402, and 140. L And three FF microphones: 1001, 1002, and 100. J They are mounted on housing 520, and FF microphones 1001, 1002, and 100... J They are respectively positioned facing the drives 1401, 1402 and 140 via the housing 520. L At the location. Note the FF microphones 1001, 1002, ..., and 100. J The location is not limited to this example.

[0215] Figure 13A This is a schematic diagram illustrating an example configuration of an acoustic output device according to a second embodiment. Figure 13A In the configuration shown, the settings correspond to J FF microphones 1001, 1002, ..., and 100 respectively. J J microphone amplifiers 1101, 1102, ..., and 110 J replace Figure 3A The microphone amplifier 110 is shown in the configuration shown.

[0216] In addition, Figure 13A In China, unlike Figure 3A The ADC 200 and DSP 300a shown are configured to support signals from the respective J microphone amplifiers 1101, 1102, ..., and 110. J Outputs multiple channels of audio signals.

[0217] Figure 13B This is a functional block diagram illustrating an example of the functionality of the DSP 300b according to the second embodiment. Figure 13B In the middle, the FFNC filter 320b includes corresponding to Figure 13A The multiple microphone amplifiers 1101, 1102, ..., and 110 shown in the figure Jand L drives 1401, 1402, ..., and 140 L The functions of (J×L) FFNC filters are configured to output corresponding to drivers 1401, 1402, ..., 140 L L noise cancellation signals. Cancellation amount control unit 321 FF It includes the function of adjusting the amount of noise cancellation for each of the L noise cancellation signals.

[0218] Figure 14 This is a diagram illustrating the configuration of the acoustic output device according to the second embodiment using a transfer function. It should be noted that... Figure 14 This shows one of the left and right configurations of the headphones 53. Figure 14 The configuration shown includes the above. Figure 4 The diagram shows multiple sets of FF microphones and microphone amplifiers 110, and further includes multiple FFNC filters 120 for each of the multiple sets.

[0219] Specifically, the earphone 53 includes transfer functions M1, M2, ..., and M..., respectively. J A set of FF microphones 1001 and microphone amplifier 1101, a set of FF microphones 1002 and microphone amplifier 1102, ..., and a set of FF microphones 100 J and microphone amplifier 110 J Noise 20 is generated by FF microphones 1001, 1002, ..., and 100. J via spaces 211, 212, ... and 21 J Collect, the spaces 211, 212, ..., and 21 J These are the spatial transfer functions X1, X2, ..., and X... J And from microphone amplifiers 1101, 1102, ..., and 110 J Output.

[0220] Headphone 53 includes drivers 1401, 1402, ..., and 140 L Each of the J FFNC filters. That is, for driver 1401, there are FFNC filters 120. 11 120 21 ... and 120 J1 They each have a filter coefficient α 11 α 21 , ..., and α J1 Includes an FFNC filter 120 for driver 1402. 12 120 22 ... and 120 J2 They each have a filter coefficient α 12 α22 , ..., and α J2 Similarly, it includes a driver 140. L FFNC filter 120 1L 120 2L , ... and 120 JL It has a filtering coefficient α 1L α 2L , ..., and α JL .

[0221] FFNC filter 120 11 Up to 120 JL Depend on Figure 13B The FFNC filter 320b is implemented in the code.

[0222] exist Figure 14 In this process, the output of microphone amplifier 1101 is input to drivers 1401, 1402, ..., and 140, respectively. L The first indication of the FFNC 120 in the FFNC filter 11 120 12 ... and 120 1L The output of microphone amplifier 1102 is input to drivers 1401, 1402, ... and 140, respectively. L The second FFNC 120 indicated in the corresponding FFNC filter 21 120 22 , ... and 120 2L Similarly, microphone amplifier 110 J The outputs are input to drivers 1401, 1402, ..., and 140 respectively. L The Jth FFNC filter in the FFNC filter indicates FFNC 120. J1 120 J2 , ... and 120 JL .

[0223] FFNC filter 120 corresponding to driver 1401 11 120 21 ... and 120 J1 The outputs are summed by adder 1611 and passed to driver amplifier 1301. The corresponding FFNC filter 120 of driver 1402... 12 120 22 ... and 120 J2 The outputs are added by adder 1612 and passed to driver amplifier 1302. Similarly, corresponding to driver 140 L FFNC filter 120 1L 1202L ... and 120 JL The output is from adder 161 L The sums are then passed to the driver amplifier 130. L .

[0224] Drive amplifiers 1301, 1302, ... and 130 L And the subsequent amplifier configuration and Figure 4 The configuration shown is the same, and therefore its description is omitted here.

[0225] (3-2. Effects of the Second Embodiment)

[0226] Next, the effects of the second embodiment will be explained. It can be seen that, compared with the above... Figure 4 Compared to the single-microphone configuration shown, in Figure 14 In the multi-microphone configuration shown, the number of FFNC filters is further increased, and the degrees of freedom for the filter coefficients α are further increased. In the multi-microphone configuration, noise cancellation performance is improved compared to the single-microphone configuration.

[0227] Figure 15 This is a schematic diagram illustrating the outline of noise cancellation according to the second embodiment. Here, it is shown that the noise 20 originates from above the earphone 53. The noise 20 is first collected by the FF microphone 1002 disposed on the upper part of the housing 520 (step S10). The noise 20 further leaks into the housing 520 (step S11). The earphone 53 generates a noise cancellation signal based on the noise 20 collected by the FF microphone 1002, and the generated noise cancellation signal is reproduced by the driver 1402 (step S12).

[0228] Noise 20 is also collected by an FF microphone 1001 located in the center of housing 520 (step S13). The earphone 53 generates a noise cancellation signal based on the noise 20 collected by the FF microphone 1001, and the generated noise cancellation signal is reproduced by the driver 1401 (step S14).

[0229] The cancellation signal reproduced by driver 1402 and the cancellation signal reproduced by driver 1401 are synthesized in the space within housing 520 to generate a wavefront (step S15). The noise 20 leaked into housing 520 in step S11 is canceled at the location of eardrum 61 by the wavefront based on the cancellation signal generated in step S15.

[0230] As described above, by using multiple FF microphones 1001, 1002, ..., and 100 JThe multiple FF microphones 1001, 1002, ..., 1004, arranged on the housing 520, can collect sound before it reaches the eardrum 61, perform filtering through an FFNC filter, and immediately reproduce the cancellation signal from a driver positioned near where the noise 20 has already leaked. Therefore, cancellation performance is improved compared to a single-microphone configuration. That is, the noise cancellation performance can be considered improved by the multiple FF microphones 1001, 1002, ..., 1004, arranged on the housing 520. J Analyze the direction of noise 20 and from drivers 1401, 1402, ..., and 140 L The driver corresponding to the incoming direction immediately reproduces the cancellation signal to improve the situation.

[0231] (Comparison with existing technologies)

[0232] Figure 16 This is a schematic diagram illustrating noise cancellation (single microphone / single driver configuration) according to the prior art. In existing single microphone / single driver configurations, such as... Figure 16 As shown in part (a), noise 20 in the lateral direction from an FF microphone positioned at the center of housing 520 via path D can be reproduced by generating a cancellation signal before the noise 20 reaches the eardrum 61. Therefore, leakage noise 20 leaking from above housing 520 via path E can be eliminated.

[0233] This is because t α +t NC ≤t N Always maintain, where time t N It is the time until the noise 20 leaks through path E to the position of eardrum 61, time t α This is the time used to generate the cancellation signal through the FFNC filter 120, and time t NC It is the time used to make the canceled sound from the reproduction canceled signal from the driver 140 reach the position of the eardrum 61.

[0234] However, as Figure 16 As shown in part (b), in the case where noise 20 arrives from above the housing 520, the noise 20 leaking through path E' reaches the position of the eardrum 61 before the signal is canceled, and remains at t α +t NC >t N Therefore, the cancellation performance deteriorates compared to the case of canceling noise 20 from the lateral direction. As described above, by employing a multi-microphone / multi-driver configuration according to the second embodiment as the noise cancellation headphone, the cancellation performance can be improved compared to the existing single-microphone / single-driver configuration.

[0235] [4. Third Implementation Method]

[0236] Next, a third embodiment will be described. The third embodiment employs a feedback (FB) method as a noise cancellation method, wherein leakage noise in the housing 520 is collected by a microphone disposed within the housing 520, and leakage noise at the location of the eardrum 61 is cancelled based on the collected leakage noise. In the third embodiment, in a multi-microphone / multi-driver configuration, multiple microphones for noise cancellation are configured as internal microphones within the housing 520 and are used as FB method microphones (FB microphones).

[0237] (4-1. Prior Art)

[0238] First, for ease of understanding, the FB method of noise cancellation using a single microphone / single driver, based on existing technology, will be described. Figure 17 This is a diagram illustrating the configuration of a noise cancellation headset based on the existing single-microphone / single-driver FB method using a transfer function.

[0239] Noise 20 via spatial transfer function F FB The leakage noise from space 24 into housing 520 and the noise cancellation sound reproduced by driver 140 and transmitted through space 25 in housing 520 via space transfer function H are synthesized by the space within housing 520 through addition unit 162. The sound synthesized by addition unit 162 is collected by FB microphone 101. The sound pressure at the location of FB microphone 101 is called sound pressure p. FB .

[0240] The audio signal output from the FB microphone 101 is provided to the microphone amplifier 111 and amplified. The transfer function of the FB microphone 101 and the microphone amplifier 111 is (M). The output of the microphone amplifier 111 is passed to the FBNC filter 121 with a filter coefficient of -β to perform noise cancellation (NC) using the FB method.

[0241] The FBNC filter 121 generates a noise cancellation signal based on the input signal to generate a noise cancellation sound. The noise cancellation signal generated by the FBNC filter 121 is amplified by a driver amplifier 130 with transfer function A and drives a driver 140 with transfer function D. The driver 140 generates a noise cancellation sound by air vibration according to the noise cancellation signal. The noise cancellation sound is transmitted from the driver 140 to a control point (e.g., the eardrum of a user wearing headphones) via space 25. At this time, as described above, the noise cancellation sound is combined with the noise 20 leaking into the housing by the adder unit 162 and reaches the position of the eardrum 61. As a result, the sound reaching the position of the eardrum 61 is the sound in which the leaked noise is eliminated by the noise cancellation sound.

[0242] In this configuration, the sound pressure level p at the location of the FB microphone 101 FB It is represented by the following expression (5).

[0243]

[0244] (4-2. Configuration according to the third embodiment)

[0245] Next, the configuration according to the third embodiment will be described. Figure 18 This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a multi-microphone / multi-driver FB method noise cancellation headset 54 according to a third embodiment. Hereinafter, "multi-microphone / multi-driver FB method noise cancellation headset 54" will be simply referred to as "headset 54". It should be noted that... Figure 18 The left and right housings of the earphone 54 are shown, with the right housing 520 being the right housing.

[0246] exist Figure 18 In the earphone 54 shown, there are L drivers 1401, 1402, ..., and 140... L Set within housing 520, with reference Figure 2 The headphones described are the same as those in model 50. Figure 18 In this example, assuming L=3, there are three drives: 1401, 1402, and 140... L Mounted on housing 520. Drivers 1401, 1402, and 140 L The alignment direction is not limited to Figure 12 The vertical direction shown in the figure can be either horizontal or inclined.

[0247] The earphone 54 has K FB microphones 1011, 1012, ..., and 101 inside the housing 520. K In the example shown, the three drives are 1401, 1402, and 140. L And three Facebook microphones: 1011, 1012, and 101. K Set within housing 520, and FB microphones 1011, 1012, and 101... K The corresponding drivers 1401, 1402 and 140 are respectively oriented towards the housing 520. L Settings. FB microphone 1011, 1012, ..., and 101 K The location is not limited to this example.

[0248] Figure 19A This is a schematic diagram illustrating an example configuration of an acoustic output device according to a third embodiment. Figure 19A The configuration shown in the image is the same as... Figure 3AThe difference in the configuration shown is that the settings correspond to K FB microphones 1011, 1012, ..., and 111 respectively. K K microphone amplifiers 1111, 1112, ..., and 101 K Instead of microphone amplifier 110.

[0249] In addition, unlike Figure 3A The ADC 200 and DSP 300a shown in the image are... Figure 19A In this configuration, the ADC 200b and DSP 300c are configured to support K microphone amplifiers 1111, 1112, ..., and 111. K Outputs multiple channels of audio signals.

[0250] Figure 19B This is a functional block diagram used to explain an example of the function of the DSP 300c according to the third embodiment. Figure 19B In the FBNC filter 320c, there are corresponding Figure 19A The multiple microphone amplifiers 1111, 1112, ..., and 111 shown in the figure K And L drives 1401, 1402, ..., and 140 L The functions of (K×L) FBNC filters are configured to output corresponding to drivers 1401, 1402, ..., 140... L L noise cancellation signals. Cancellation amount control unit 321 FB This includes the ability to adjust the amount of noise cancellation for each of the L noise cancellation signals.

[0251] Headphone 54 is based on FB microphones 1011, 1012, ..., and 101. K The output audio signal is generated by FB microphones 1011, 1012, ..., and 102. K The corresponding FBNC filter and the drivers 1401, 1402, ..., 140 in the FBNC filter 320c. L Noise cancellation signal is generated. This is achieved through drivers 1401, 1402, ..., 140... L The generated noise-cancelled signal is reproduced to achieve noise cancellation via the FB method.

[0252] Figure 20 This is a diagram illustrating the configuration of an acoustic output device according to a third embodiment using a transfer function. For illustrative purposes, Figure 20 An example using a single FB microphone 101 (K=1) is shown. Furthermore, Figure 20 One of the left and right configurations of the headset 54 is shown. Figure 20The configuration shown is as follows: via multiple drives 1401, 1402, ..., and 140 L Parallel connection according to Figure 17 The configuration of the FBNC filter 121, drive amplifier 130, driver 140, and space 25 in the prior art configuration shown is illustrated.

[0253] exist Figure 20 In, via drivers 1401, 1402, ... and 140 L The noise-cancelled sounds obtained by reproducing the noise-cancelled signals are respectively transmitted through spatial transfer functions H1, H2, ..., and H L Spaces 251, 252, ... and 25 L The noise 20 reaches the addition unit 163 within the housing 520. Furthermore, the noise 20 is transmitted via the spatial transfer function F. FB Space 24 leaks into housing 520 and reaches addition unit 163 as leakage noise. Synthesis is achieved through drivers 1401, 1402, ..., 140 L The noise-cancelled sound and leakage noise obtained by reproducing the noise cancellation signal are collected by the FB microphone 101, where the leakage noise is eliminated.

[0254] The output of the FB microphone 101 is passed to devices with filter coefficients -β1, -β2, ..., -β1 respectively. L FBNC filters 1211, 1212, ... and 121 L FBNC filters 1211, 1212, ..., and 121 L Depend on Figure 19B The FBNC filter 320c is implemented.

[0255] exist Figure 20 In the diagram, FBNC filters 1211, 1212, ..., and 121... L The output of the FB microphone 101 generates signals corresponding to drivers 1401, 1402, ..., and 140. L L noise cancellation signals. These L noise cancellation signals are driven by corresponding amplifiers 1301, 1302, ..., 130... L Amplified and driven by drivers 1401, 1402, ..., and 140 L Reappearance.

[0256] In noise cancellation using the FB method, the sound pressure level p at the location of the FB microphone 101 can be reduced. FB .based on Figure 20 The configuration yields the following expression (6).

[0257]

[0258] When transforming expression (6), the following expression (7) is obtained.

[0259]

[0260] In expression (7), by designing FBNC filters 1211, 1212, ..., 121 L The filter coefficients β1, β2, ..., β L This increases the value on the denominator side, resulting in a higher sound pressure level p at the location of the FB microphone 101. FB Approaching 0, and can further enhance the noise cancellation effect. Note the filter coefficients β1, β2, ..., β... L It needs to be designed to address issues such as jitter.

[0261] The expression (7) based on the single-microphone / multi-driver FB method will be compared with the expression (5) based on the single-microphone / single-driver FB method described above. In this case, in the multi-driver expression (7), the drivers 1401, 1402, ..., and 140 are respectively... L The filter coefficients β1, β2, ..., β L The sum of the products contributed to the denominator side allows for an increase in the denominator side and improves elimination performance.

[0262] Figure 21 This is a diagram showing the configuration of an acoustic output device according to a third embodiment using a transfer function. Figure 21 The configuration shows that in such Figure 18 The cross-sectional view of the headset 54 shown in the figure includes K FB microphones 1011, 1012, ..., and 101. K An example of a situation. In Figure 21 In the example, K FB microphones 1011 to 101 K and L drives 1401 to 140 L It is located in housing 520. FB microphone 1011 to 101 K The sound pressures in the values ​​are set as sound pressures p1, p2, ..., p, respectively. K .

[0263] exist Figure 21 In the process, the output of the FB microphone 1011 is input to a microphone amplifier 1111 via a filter coefficient -β. 11 -β 12 ... and -β 1L FBNC filter 121 11 121 12 ... and 121 1LThe output of the FB microphone 1012 is input to the microphone amplifier 1112 via microphone amplifiers, each having a filter coefficient -β. 21 , -β 22 , ..., and -β 2L The FBNC filter. Then, similarly, the FB microphone 101... K The output is via microphone amplifier 111 K They are respectively input to a filter with a coefficient -β K1 , -β K2 , ..., and -β KL FBNC filter 121 K1 121 K2 ... and 121 KL .

[0264] FBNC filter 121 11 Up to 121 KL Depend on Figure 19B The FBNC filter 320c is implemented.

[0265] exist Figure 21 In the middle, the adder 1641 will take the FBNC filter 121 11 ,121 21 , ..., and 121 K1 The output noise cancellation signals are added together and combined into a single noise cancellation signal. The combined noise cancellation signal output from adder 1641 is amplified by driver amplifier 1301 and reproduced by driver 1401.

[0266] From FBNC filter 121 12 ,121 22 , ..., and 121 K2 The output noise cancellation signals are added by adder 1642 and combined into a single noise cancellation signal. The combined noise cancellation signal output from adder 1642 is amplified by driver amplifier 1302 and reproduced by driver 1402.

[0267] Subsequently, similarly, from FBNC filter 121 1L ,121 2L , ..., and 121 KL The output noise cancellation signal is generated by adder 164. L The signals are added and combined into a noise-cancelled signal. From adder 164... L The output synthesized noise cancellation signal is driven by amplifier 130. L Amplified, and driven by driver 140 L Reappearance.

[0268] The noise-cancelled sound reproduced by the driver 1401 is transmitted via the spatial transfer function H. 11H 12 , ..., and H 1K Space 25 in the shell 520 11 25 12 , ... and 25 1K Adding units 1631, 1632, ..., and 163 reach housing 520 K .

[0269] The noise-cancelled sound reproduced by the driver 1402 is transmitted via the spatial transfer function H 21 H 22 , ..., and H 2K Space 25 in the shell 520 21 25 22 , ... and 25 2K Adding units 1631, 1632, ..., and 163 reach housing 520 K .

[0270] Similarly, the following is from driver 140 L The reproduced noise-cancelled sounds are respectively transmitted via the spatial transfer function H L1 H L2 , ..., and H LK The space 25 inside the shell 520 L1 25 L2 , ... and 25 LK Adding units 1631, 1632, ..., and 163 reach housing 520 K .

[0271] Furthermore, noise 20 is transmitted via the spatial transfer function F FB1 Space 241 reaches adder 1631. In adder 1631, synthesis is achieved via space 25. 11 25 21 , ... and 25 L1 The FB microphone 1011 collects the noise cancellation sound that arrives and the leakage noise that arrives via space 241. The noise cancellation sound canceled by the noise cancellation sound from the leakage noise is collected.

[0272] Furthermore, noise 20 is transmitted via the spatial transfer function F FB2 Space 242 reaches adder 1632. In adder 1632, synthesis is achieved via space 25. 12 25 22 ... and 25 L2 The noise cancellation sound arrives and the leakage noise arrives via space 242, and the FB microphone 1012 collects the noise cancellation sound from the leakage noise.

[0273] Similarly, noise 20 is further transmitted via the spatial transfer function FFBK Space 24 K Reaching addition unit 163 K In addition unit 163 K In the middle, synthesis via space 25 1K 25 2K , ... and 25 LK Arrival noise cancellation sound and via space 24 K The arriving leakage noise, and FB microphone 101 K Collect the noise cancellation sound from the leaked noise.

[0274] exist Figure 21 For example, when focusing on the sound pressure level p1 at the FB microphone 1011, from Figure 21 The corresponding transfer function in the expression is given by the following expression (8).

[0275]

[0276]

[0277] Expression (8) is organized into the following expression (9).

[0278]

[0279] When the left side of expression (9) is organized by sound pressure p1, we get the following expression (10).

[0280]

[0281] When expression (10) is organized by sound pressure p1, the following expression (11) is obtained.

[0282]

[0283] In expression (11), by using FBNC filter 121 11 Up to 121 1L ,121 21 Up to 121 2L , and 121 K1 Up to 121 KL The design uses a large denominator to eliminate leakage noise. The difference between expression (11) and the aforementioned expression (7) for a multi-driver single-type FB method is that the numerator of expression (11) comes from FB microphones 1012, ..., 101, other than the FB microphone 1011 of interest. K The sum of the FB component and leakage noise.

[0284] Note that although the description here focuses on FB1011 for descriptive purposes, the descriptions of other FB microphones 1012 through 101 can be similarly derived. K .

[0285] [5. Fourth Implementation Method]

[0286] Next, a fourth embodiment of this disclosure will be described. The fourth embodiment is an example of noise cancellation achieved in a multi-microphone / multi-driver noise-cancelling headset by combining the FF method and the FB method. Hereinafter, the noise cancellation method combining the FF method and the FB method is appropriately referred to as the dual method.

[0287] Figure 22 This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a multi-microphone / multi-driver dual-method noise cancellation headset 55 according to the fourth embodiment. Hereinafter, "multi-microphone / multi-driver dual-method noise cancellation headset 55" will be simply referred to as "headset 55". It should be noted that... Figure 22 The left and right housings of the earphone 55 are shown, with the right housing 520 being one of them.

[0288] like Figure 22 As shown, the earphone 55 according to the fourth embodiment has a combination reference. Figure 12 The described headphones 53 and reference Figure 18 The described configuration of the headphones 54 is as follows: Specifically, the headphones 55 have multiple drivers 1401, 1402, ..., 1403 within the housing 520 for noise cancellation using the FB method. L And multiple Facebook microphones 1011, 1012, ..., and 101 K Furthermore, the earphone 55 is provided with a plurality of FF microphones 1001, 1002, ..., and 100 for noise cancellation using the FF method, facing outwards from the housing 520. J .

[0289] Figure 23A This is a schematic diagram illustrating an example configuration of an acoustic output device according to the fourth embodiment. Figure 23A The configuration shown is Figure 13A The above configuration and Figure 19A The combination of configurations in the middle.

[0290] That is, FF microphones 1001, 1002, ..., and 100 J The outputs are respectively transmitted through microphone amplifiers 1101, 1102, ..., and 110 J Input to ADC 200b. ADC 200b will output from microphone amplifiers 1101, 1102, ..., and 110... JEach input audio signal is converted into a digital audio signal and then provided to the DSP 300d.

[0291] Similarly, FB microphones 1011, 1012, ..., and 101 K The outputs are respectively transmitted through microphone amplifiers 1111, 1112, ..., and 111 K The input is fed into the ADC 200c. The ADC 200c will input from microphone amplifiers 1111, 1112, ..., and 111. K Each input audio signal is converted into a digital audio signal and then provided to the DSP 300d.

[0292] Figure 23B This is a functional block diagram used to explain an example of the function of the DSP 300d according to the fourth embodiment. Figure 23B The configuration shown has the combination of the above Figure 13B The DSP 300b shown is... Figure 19B The configuration of DSP 300c is shown below. Specifically, DSP 300d includes FF microphones 1001, 1002, ..., and 100. J The corresponding FFNC filter 320b and cancellation control unit 321 FF And with FB microphones 1011, 1012, ..., and 101 K The corresponding FBNC filter 320c and cancellation control unit 321 FB Each output of ADC 200b is input to FFNC filter 320b. Furthermore, each output of ADC 200c is input to FBNC filter 320c.

[0293] Figure 24 This is a diagram illustrating the configuration of an acoustic output device according to the fourth embodiment using a transfer function. Noise cancellation via the FF method and noise cancellation via the FB method can be controlled independently of each other. Therefore, Figure 24 The configuration shown is noise cancellation via a multi-microphone / multi-driver FF method. Figure 14 The configuration and noise cancellation via the multi-microphone / multi-driver FB method described above Figure 21 The combination of configurations. It should be noted that in Figure 24 In the middle, the j-th (1≤j≤J) FF microphone 100 j and microphone amplifier 110 j The transfer function is (M FFj And the kth (1≤k≤K) FB microphone 101 k and microphone amplifier 111 k The transfer function is (MFBk ).

[0294] First, the description and Figure 24 The configuration related to noise cancellation using the FF method in the headphone 55. The headphone 55 includes transfer functions M... FF1 M FF2 , ..., and M FFJ A set of FF microphones 1001 and microphone amplifier 1101, a set of FF microphones 1002 and microphone amplifier 1102, ..., and a set of FF microphones 100 J and microphone amplifier 110 J Noise 20 is generated by FF microphones 1001, 1002, ..., and 100. J via spaces 211, 212, ..., and 21 J Collection, the spaces 211, 212, ..., and 21 J These are the spatial transfer functions X1, X2, ..., and X. J And from microphone amplifiers 1101, 1102, ..., and 110 J Output.

[0295] The output of microphone amplifier 1101 is input to FFNC 120. 11 120 12 , ... and 120 1L FFNC 120 11 120 12 , ... and 120 1L Each of the components generates a noise cancellation signal based on the output of microphone amplifier 1101, and inputs the generated noise cancellation signal to adders 1651, 1652, ..., 1653. L Each of them.

[0296] The output of microphone amplifier 1102 is input to FFNC 120. 21 120 22 , ... and 120 2L FFNC 120 21 120 22 , ... and 120 2L Each of the components generates a noise cancellation signal based on the output of microphone amplifier 1102, and the generated noise cancellation signal is input to adders 1651, 1652, ..., 165... L Each of them.

[0297] Similarly, microphone amplifier 110 J The output is input to FFNC 120 J1 120 J2 ... and 120JL FFNC120 J1 120 J2 ... and 120 JL Each of the microphone amplifiers 110 J The output generates a noise cancellation signal, which is then input to adders 1651, 1652, ..., and 165. L Each of them.

[0298] Next, the configuration related to noise cancellation using the FB method will be described. The headset 55 includes transfer functions M... FB1 M FB2 ... and M FBK A set of FB microphones 1011 and microphone amplifier 1111, a set of FB microphones 1012 and microphone amplifier 1112, ..., and a set of FB microphones 101 K and microphone amplifier 111 K FB microphones 1011, 1012, ..., and 101 K Collect addition units 1631, 1632, ..., and 163 respectively. K The output, and from microphone amplifiers 1111, 1112, ..., and 111 K The sound signal collected from each output.

[0299] The output of microphone amplifier 1111 is input to FBNC filter 121. 11 ,121 12 , ..., and 121 1L The output of microphone amplifier 1112 is input to FBNC filter 121. 21 ,121 22 , ..., and 121 2L Subsequently, similarly, microphone amplifier 111 K The output is input to FBNC filter 121 K1 121 K2 ... and 121 KL .

[0300] From FBNC filter 121 11 121 21 ... 121 K1 The output noise cancellation signals are input to adder 1651. Adder 1651 will then process the noise cancellation signals from FFNC filter 120. 11 120 21 120 J1 The output noise cancellation signals and the signals from FBNC filter 121 11 12121 ... 121 K1 The output noise cancellation signals are synthesized. The synthesized noise cancellation signal output from adder 1651 is amplified by driver amplifier 1301 and reproduced by driver 1401.

[0301] From FBNC filter 121 12 ,121 22 , ..., and 121 K2 The output noise cancellation signals are input to adder 1652. Adder 1652 will then draw noise from FFNC filter 120. 12 120 22 , ... and 120 J2 The output noise cancellation signals and the signals from the FBNC filter 121 12 ,121 22 , ..., and 121 K2 The output noise cancellation signals are synthesized. The synthesized noise cancellation signal output from adder 1652 is amplified by driver amplifier 1302 and reproduced by driver 1402.

[0302] Then, similarly, from FBNC filter 121 1L ,121 2L , ..., and 121 KL The output noise cancellation signals are input to adder 165. L Adder 165 L From FFNC filter 120 1L 120 2L , ... and 120 JL The output noise cancellation signals and the FBNC filter 120 1L 120 2L , ... and 120 KL The output noise-cancelled signals are synthesized. From adder 165 L The output synthesized noise cancellation signal is driven by amplifier 130. L Amplified and driven by driver 140 L Reappearance.

[0303] The noise-cancelled sounds reproduced by the driver 1401 pass through the space 25 in the housing 520 respectively. 11 25 12 , ... and 25 1K Addition units 1631, 1632, ..., and 163 reach the housing 520 K The noise-cancelled sound reproduced by the driver 1402 passes through the space 25 in the housing 520. 21 25 22 , ... and 252K Adding units 1631, 1632, ..., and 163 reach housing 520 K Similarly, the following is from driver 140 L The reproduced noise cancellation sound is transmitted through the space 25 in each housing 520. L1 25 L2 , ..., 25 LK Addition units 1631, 1632, ..., 163 reach the housing 520 K .

[0304] Furthermore, noise 20 is transmitted via spaces 241, 242, ..., and 24 respectively. K Reaching addition units 1631, 1632, ..., and 163 K .

[0305] In addition unit 1631, synthesis is achieved via space 25 11 25 21 , ... and 25 L1 The FB microphone 1011 collects the noise cancellation sound that arrives and the leakage noise that arrives via space 241. The noise cancellation sound canceled by the noise cancellation sound from the leakage noise is collected.

[0306] In addition unit 1632, synthesis is achieved via space 25. 12 25 22 , ... and 25 L2 The noise cancellation sound arrives and the leakage noise arrives via space 242, and the FB microphone 1012 collects the sound canceled by the noise cancellation sound from the leakage noise.

[0307] Subsequently, in a similar manner, in addition unit 163 K In the middle, synthesis via space 25 1K 25 2K , ... and 25 LK Arrival noise cancellation sound and via space 24 K The arriving leakage noise, and FB microphone 101 K Collect the noise cancellation sound from the leaked noise.

[0308] In addition, drives 1401, 1402, ..., and 140 L The noise cancellation of the reproduced FF method is achieved by transmitting noise-cancelled sounds through spaces 231, 232, and 23 in the housing 520, respectively. L The noise cancellation sound of the FF method is combined into a single noise cancellation sound by the addition unit 160 and reaches the user's eardrum 61 as a sound pressure (p).

[0309] According to the configuration of the fourth embodiment, residual noise in the housing 520 that was not eliminated by the noise cancellation method can be eliminated by the noise cancellation method of the FB method. Therefore, noise cancellation performance can be further improved compared to the case where one of the noise cancellation methods of the multi-microphone / multi-driver FF method and the multi-microphone / multi-driver FB method is performed.

[0310] [6. Fifth Implementation Method]

[0311] Next, a fifth embodiment of this disclosure will be described. In the fifth embodiment, headphones with a plurality of drivers 140 disposed within a housing 520 can be used to reproduce realistic 3D (3D) audio content.

[0312] As a form of real-world 3D audio content, there exists object-based sound content. In object-based sound, one or more audio signals used as sound material are considered a sound source (called an object sound source), and metadata is added to the object sound source. Instances of metadata added to the object sound source include location information.

[0313] For example, the decoding of an object sound source, including location information as metadata, adds additional metadata, and the decoded metadata is reproduced by a loudspeaker system corresponding to the object's sound, so that the sound image of the object sound source can be located at the location based on the location information, or the location of the sound image can be moved along the time axis. As a result, realistic sound can be represented.

[0314] In headphones with multiple drivers 140 installed in the housing 520, the user can enjoy a realistic acoustic experience by reproducing object sound sources, 3D audio content sound sources, etc. from each driver 140.

[0315] Figure 25A This is a schematic diagram used to illustrate the reproduction of an object sound source according to the fifth embodiment. Figure 25A In this embodiment, the earphone 56 has multiple (three in this example) drivers 1401, 1402 and 1403 disposed within the housing 520. More specifically, driver 1401 is disposed substantially at the center of the housing 520, driver 1402 is disposed on the upper side of the housing 520 and driver 1403 is disposed on the lower side of the housing 520.

[0316] For example, location information is added to each of the object sound sources 6001, 6002, and 6003 as metadata. For example, the object sound sources 6001, 6002, and 6003 are input to a positioning filter 1701 with filtering coefficient W1, a positioning filter 1702 with filtering coefficient W2, and a positioning filter 1703 with filtering coefficient W3, such as an equalizer (EQ).

[0317] For example, the localization filter 1701 decodes the metadata added to the input object sound source 6001 and extracts the location information included in the metadata. For example, the localization filter 1701 outputs the object sound source 6001 to the driver 1401 associated with the extracted location information. As a result, the driver 1401 outputs the reproduced sound 6011 obtained by reproducing the object sound source 6001.

[0318] This also applies to positioning filters 1702 and 1703. That is, positioning filters 1702 and 1703 decode the input object sound sources 6002 and 6003, respectively, and extract the positional information included in the metadata. For example, positioning filters 1702 and 1703 output the object sound sources 6002 and 6003 to drivers 1402 and 1403 associated with the extracted positional information, respectively. As a result, drivers 1402 and 1403 output the reproduced sounds 6012 and 6013 obtained by reproducing the object sound sources 6002 and 6003, respectively.

[0319] As described above, by appropriately assigning object sound sources 6001 to 6003 to drivers 1401 to 1403 provided in housing 520 based on meta-information, object sound sources 6001 to 6003 can respectively reproduce realistic sound sources 6012 to 6013.

[0320] In the above description, it is stated that the positioning of each object sound source 6001 to 6003 is fixed during reproduction, but this is not limited to this example. For example, the positioning of the reproduced sounds 6012 to 6013 of object sound sources 6001 to 6003 may be moved respectively during the reproduction of object sound sources 6001 to 6003. In this case, for example, it is conceivable to include the movement information in the metadata added to each of the object sound sources 6001 to 6003.

[0321] Figure 25B This is a schematic diagram illustrating the state of positioning the reproduced sound when reproducing an object sound source according to the fifth embodiment. In this example, object sound sources 6001, 6002, and 6003 are reproduced from all drivers 1401, 1402, and 1403, and processing is performed by filters that provide delay or amplitude. As a result, the movement of reproduced sounds 6012, 6012, and 6013 of object sound sources 6001, 6002, and 6003 is achieved.

[0322] exist Figure 25B In the process, the sound source 6001 is input to the filter with filtering coefficient W. 11 W 12 and W 13 Positioning filter 170 11 170 12and 170 13 The sound source 6002 is input to a filter with filtering coefficients W. 21 W 22 and W 23 Positioning filter 170 21 17022 and 170 23 Similarly, the target sound source 6003 is input to a circuit with filtering coefficients W. 31 W 32 and W 33 Positioning filter 170 31 170 32 and 170 33 .

[0323] Positioning Filter 170 11 Up to 170 13 The input metadata of each decoded object sound source 6001 is processed, and its position and movement information are extracted. Localization filter 170 11 Up to 170 13 Based on the extracted position and movement information, the level and delay assignments of the drivers 1401, 1402, and 1403 of the object sound source 6001 are determined respectively. As a result, the reproduced sound 6011 of the object sound source 6001 can move within the housing 520.

[0324] This also applies to the positioning filter 170. 21 Up to 170 23 and positioning filter 170 31 Up to 170 33 Positioning filter 170 21 Up to 170 23 and positioning filter 170 31 Up to 170 33 The input metadata of object sound sources 6002 and 6003 are decoded respectively to extract position and movement information. Based on the extracted position and movement information, the level and delay assignment of the drivers 1401, 1402, and 1403 for object sound sources 6002 and 6003 are determined. As a result, as described above, the reproduced sound 6012 of object sound source 6002 and the reproduced sound 6013 of object sound source 6003 can move within the housing 520.

[0325] As described above, by using an earphone 56 having multiple drivers 1401 to 1403 in the housing 520, and respectively through a positioning filter 170 11 Up to 170 33 By outputting the object sound sources 6001 to 6003 to the drivers 1401 to 1403, the user can be given the experience that the sound image is moving.

[0326] Figure 26A This is a schematic diagram illustrating an example configuration of an acoustic output device according to the fifth embodiment. Figure 25A In this example, the acoustic output device includes headphones 56, driver amplifiers 130a, 130b, and 130c, a DAC 201, a memory 210, an operation unit 211, and a DSP 300e. The target sound source 710, corresponding to the aforementioned target sound sources 6001 to 6003, is input to the DSP 300e.

[0327] Figure 26B This is a functional block diagram used to explain an example of the function of the DSP 300e according to the fifth embodiment. Figure 26B In the DSP 300e, a positioning filter 170, a horizontal control unit 312, and a control unit 310 are included. The positioning filter 170 implements, for example... Figure 25B The positioning filter 170 shown 11 Up to 170 33 The object sound source 710 input to the DSP 300e is passed to the localization filter 170. The localization filter 170 decodes the object sound source 710 and, for example, sets the localization of the object sound source 710 based on the metadata added to the object sound source 710.

[0328] Positioning filter 170 generates an output signal (audio signal) to be provided to each of drivers 140a, 140b, and 140c according to a set positioning, and transmits the generated output signal to level control unit 312. Level control unit 312 adjusts the level of the output signal provided to each of drivers 140a, 140b, and 140c according to instructions from control unit 310, for example, based on user operation on operation unit 211. The level-adjusted output signal is provided to drivers 140a, 140b, and 140c and reproduced as sound.

[0329] Figure 27 This is a diagram illustrating the configuration of an acoustic output device according to a fifth embodiment using a transfer function. Assume the target sound sources are 6001, 6002, ..., and 600... N They have transfer functions O1, O2, ..., and O respectively. N As an acoustic property.

[0330] The target sound sources are 6001, 6002... and 600. N They were respectively input to drives 1401, 1402... and 140 L Corresponding positioning filter 170 11 Up to 170 N1 Positioning filter 170 12 Up to 170 N2 and positioning filter 1701L Up to 170 NL Specifically, the target sound source 6001 is input to the localization filter 170. 11 170 12 , and 170 1L The sound source 6002 is input to the localization filter 170. 21 170 22 , and 170 2L Similarly, the target sound source 600 was then... N Input to positioning filter 170 N1 170 N2 , and 170 NL .

[0331] Positioning Filter 170 11 Up to 170 N1 The output is synthesized by adder 1661, and after gain adjustment by gain adjustment unit 1801 with transfer function V1, it is input to drive amplifier 1301 and reproduced from driver 1401. Positioning filter 170 12 Up to 170 N2 The output is synthesized by adder 1662, and after gain adjustment by gain adjustment unit 1802 with transfer function V2, it is input to drive amplifier 1302 and reproduced from driver 1402. Similarly, the positioning filter 170... 1L Up to 170 NL The output is from adder 166 L Composition, in which a transfer function V is used L Gain adjustment unit 180 L After adjusting the gain, the signal is input to the driver amplifier 130. L And from drive 140 L Reappearance.

[0332] Drives 1401, 1402, ..., and 140 L The reproduced sounds are generated by the addition unit 160 in the housing 520 via spatial transfer functions G1, G2, ..., and G in the housing 520. L Spaces 231, 232, ..., and 23 L The sound pressure 150, as a sound pressure (p), is synthesized and reaches the position of the eardrum 61.

[0333] As described above, in the fifth embodiment, due to the multiple drivers 1401, 1402, ... and 140... L The placement on the housing 520 increases the degree of freedom of the positioning filter 170, which is beneficial for acoustic image positioning.

[0334] (6-1. Variations of the fifth embodiment)

[0335] The configuration for performing noise cancellation can be combined with the configuration for reproducing the object sound source according to the fifth embodiment described above. Figure 28A This is a schematic diagram illustrating an example configuration of an acoustic output device according to a variation of the fifth embodiment.

[0336] Figure 28A The configuration described herein will incorporate the functionality of the object sound source 710 into the configuration described above. Figure 23A In the configuration described herein, in this case, the DSP 300f corresponding to the processing of the target sound source is used instead of the one described above. Figure 23A The DSP 300d is shown in the image, and the object sound source 710 is input to the DSP 300f instead of the DSP 300d. Figure 23A The audio signal 700. Due to its relationship with Figure 23A The same configuration can be applied to other configurations, so its description is omitted here.

[0337] Figure 28B This is a functional block diagram illustrating an example of the function of the DSP 300f according to a variation of the fifth embodiment. Figure 28B The DSP 300f shown is... Figure 23B The difference in the DSP 300d shown is the addition of a localization filter 170. The object sound source 710 input to the DSP 300f is fed into the localization filter 170, and when driven by drivers 1401 to 140... L The localization during reproduction is set based on the metadata added to the object sound source 710. At this time, the localization filter 170 can also adjust the set localization according to instructions from the control unit 310, for example, based on user operation on the operation unit 211.

[0338] The object sound source 710, whose positioning has been set by the positioning filter 170, is passed to the adder 314 via the EQ 311 and the level control unit 312. The adder 314 synthesizes the noise cancellation signal generated by the FFNC filter 320b, the noise cancellation signal generated by the FBNC filter 320c, and the positioning-set object sound source 710 from the level control unit 312 to output them.

[0339] The output of adder 314 is converted by DAC 201 to the output of drivers 1401 to 140. L Each corresponding digital audio signal in the signal is driven by amplifiers 1301 to 1301 respectively. L Provided to drive 1401 to 140 L Each of them. Each drive 1401 to 140 L External noise can be eliminated by reproducing the sound source 710 and noise cancellation sound.

[0340] Therefore, even outdoors, users wearing the headphones can enjoy a highly realistic acoustic experience when performing noise cancellation.

[0341] [7. Sixth Implementation Method]

[0342] Next, a sixth embodiment of this disclosure will be described. In the sixth embodiment, a plurality of FF microphones 1001, 1002, ..., and 100 are disposed on the housing 520. J Used to collect noise from a specific direction and reproduce the collected noise using that specific direction as the location.

[0343] For example, consider a scenario where a vehicle approaches a user from behind while the user is wearing headphones using the technology described in Patent Document 2 outdoors. In this case, during beamforming processing using multiple FF microphones arranged on the outer part of the housing, noise from the vehicle approaching the user from behind is selectively collected and reproduced from the headphone driver, while noise from other directions is eliminated, thus attracting the user's attention.

[0344] In this case, in Patent Document 2, the number of drivers reproducing the sound signal is one driver for each of the L and R channels, and these drivers are positioned near the side of the user's ear while wearing the headphones. Therefore, for example, even when the noise of a vehicle approaching the user from behind is collected and reproduced from the drivers as described above, the user may find it difficult to be completely certain that the vehicle is approaching from behind.

[0345] In the sixth embodiment, multiple FF microphones 1001 to 100 are provided in each of the left and right housings 520. J Therefore, beamforming can be performed to enhance sound (noise) collected from a specific direction. Furthermore, multiple drivers 1401 to 140 are provided in each of the left and right housings 520. L So from drive 1401 to 140 L The driver located in the direction corresponding to the direction the sound (noise) has arrived reproduces the collected sound, or drives all drivers 1401 to 140 through signal processing. L This allows the user to reproduce the wavefront where the sound (noise) has arrived. As a result, the user can determine the direction in which the sound (noise) has arrived.

[0346] It can be considered that the collected sound is the sound reproduced by the driver located in the direction corresponding to the direction in which the sound (noise) arrives, or the sound generated due to the wavefront of the sound arrival is the acoustic control sound used to control the sound in the housing 520, and the sound signal used to reproduce the sound is the acoustic control signal used to reproduce the acoustic control sound by the driver.

[0347] Figure 29 This is a schematic diagram illustrating the reproduction control according to the sixth embodiment. Note that in the figure, the horizontal cross-section of the appearance of the left housing 520L and the right housing 520R of the earphone 53 is schematically shown, using the multi-microphone / multi-driver FF method noise cancellation earphone 53 (earphone 53) according to the second embodiment as an example.

[0348] Figure 29 The earphone 53 shown has a configuration where the left shell 520L and the right shell 520R are connected by a headband 530. Note that in the figure, the direction indicated by the white arrow is in front of the user (head 40) wearing the earphone 53.

[0349] The housing 520L includes three actuators 140 respectively arranged on the central part, the front part and the rear part. Lcnt 140 Lfwd , and 140 Lrr In addition, the housing 520L includes three FF microphones arranged outwards on the central, front, and rear portions: FF microphone 100L cent 100L fwd and 100L rr .

[0350] Similarly, housing 520R includes three actuators 140R respectively arranged on the central portion, front portion and rear portion. cnt 140R fwd and 140R rr In addition, the housing 520R includes three FF microphones arranged outwards on the central, front, and rear portions: FF microphone 100R. cent 100R fwd and 100R rr .

[0351] The earphone 53 is based on the FF microphone 100L, which is respectively located in the left shell 520L and the right shell 520R. cent 100L fwd and 100L rr And FF microphone 100R cent 100R fwd and 100R rr The output of the earphone 53 uses known beamforming techniques to detect the direction of incoming noise. The earphone 53 outputs from drivers 140 respectively arranged in the left housing 520L and right housing 520R. Lcnt 140 Lfwd , and 140 Lrr and drive 140R cnt 140Rfwd and 140R rr The driver located in the direction corresponding to the direction of entry of the detected noise reproduces the collected noise.

[0352] exist Figure 29 In one example, when noise 20L arriving from the left is detected by, for example, beamforming (BF) 80L, the earphone 53 uses a driver 140 arranged in a direction corresponding to the direction of entry of the noise 20L. Lcnt The noise 20L collected by beamforming 80L is reproduced. Similarly, when noise 20R arriving from the right is detected by beamforming 80R, the earphone 53 uses the driver 140R arranged in the direction corresponding to the direction of entry of noise 20R. cnt Reproduces the noise 20R collected by beamforming 80R.

[0353] Furthermore, when beamforming 80L rr Beamforming 80R rr Detecting noise arriving from behind 20C rr At that time, the headphones 53 are positioned in relation to noise 20C. rr The driver 140 in the direction corresponding to the direction of entry Lrr and 140R rr Reproduction via beamforming 80L rr and beamforming 80R rr Collected noise 20C rr At this point, preferably, for example, according to beamforming 80L rr Beamforming 80R rr The obtained noise 20C rr The position is controlled by the driver 140 Lrr and 140R rr Reproduced noise 20C rr Positioning.

[0354] Therefore, while eliminating noise from the front that utilizes the user's visual information, the driver can reproduce and reproduce noise from the rear and sides, which are blind spots. Thus, for example, a user wearing the headphones 53 according to the sixth embodiment can easily determine that a vehicle is approaching from behind, and the user's safety can be ensured when using the headphones 53 outdoors, thus solving the problem in Patent Document 2.

[0355] Note that the beamforming 80L rr and beamforming 80R rr Collected noise 20C rrThis is noise generated behind the user (i.e., in the direction that serves as the user's blind spot). For example, a beamforming 80L that collects noise generated in the direction that serves as the user's blind spot. rr and beamforming 80R rr This can be referred to as blind spot beamforming (BF).

[0356] Figure 30A This is a schematic diagram illustrating an example configuration of an acoustic output device according to the sixth embodiment. Figure 30A The configuration shown in Figure 13A The difference in the configuration shown is that the DSP 300g functions to beamforming, and the output of the ADC 200a is branched and input to the DSP 300g. Other configurations are as per the reference. Figure 13A The configurations described are similar, therefore, their descriptions are omitted here.

[0357] Here, for example, Figure 30A The housing 520 shown in the figure represents Figure 29 The left housing 520L and right housing 520R are shown in the diagram. Similarly, FF microphones 1001, 1002, and 100... J Corresponding to Figure 29 FF microphone 100R cent 100R fwd and 100R rr And drives 1401, 1402 and 140 L Corresponding to Figure 29 Drive 140R cnt 140R fwd and 140R rr .

[0358] It should be noted that the ADC 200a is based on the FF microphone 100L, which is respectively located on the left housing 520L and the right housing 520R. cent 100L fwd and 100L rr And FF microphone 100R cent 100R fwd and 100R rr Collect sounds to receive sound signals.

[0359] Figure 30B This is a functional block diagram used to explain an example of the function of the DSP 300g according to the sixth embodiment. Figure 30B The configuration shown is the same as described above. Figure 13B The configuration shown differs in that it includes the addition of a blind spot beamforming (BF) filter 330, a positioning filter 331, and a horizontal control unit 332.

[0360] The output of ADC 200a is input to FFNC filter 320b and blind spot BF filter 330. The processing of the audio signal 700 after the output of ADC 200a is input to FFNC filter 320b is related to the processing and reference of the audio signal 700. Figure 13B The processing described is similar, so its description is omitted here.

[0361] The blind spot BF filter 330 is based on the input from the ADC 200a and the FF microphone 100L. cent 100L fwd and 100L rr And FF microphone 100R cent 100R fwd and 100R rr The collected sound signals undergo beamforming, and noise from the blind spot (from the rear, right, etc.) of the user wearing headphones 53 is detected. A blind spot BF filter 330 generates signal from the driver 140. Lcnt and 140 Lfwd and drive 140 Lrr and drive 140R cnt and 140R fwd and drive 140R rr The driver, positioned in a location corresponding to the direction in which the noise arrives, outputs the sound signal of the detected noise (called the noise enhancement signal).

[0362] The noise enhancement signal output from the blind spot BF filter 330 is input to the positioning filter 331. The positioning filter 331 has the function of allowing the user to naturally hear the noise enhancement signal generated by the blind spot BF filter 330 (such as positioning adjustment). The level control unit 332 controls the level of the noise enhancement signal output from the positioning filter 331 via instructions from the control unit 310, for example, based on the user's operation of the operation unit 211. The noise enhancement signal output from the level control unit 332 is input to the adder 314 and combined with the noise cancellation signal and the audio signal 700 to output to the DAC 201.

[0363] It should be noted that the range of the blind spot determined by the blind spot BF filter 330 can be set by the user. For example, based on the user's operation of the operation unit 211, the range of the blind spot BF filter 330 will be determined according to the instructions from the control unit 310. The blind spot setting range can be set in any direction, as long as the multiple FF microphones are arranged outwards on each of the housings 520L and 520R of the headset 53. When the blind spot BF is set not only in the blind spot direction but in all directions, a natural external sound can be provided to the user, as if the user is not wearing headphones.

[0364] In other words, even when a user is wearing headphones, external sounds can be provided as if the user were not wearing headphones, because beamforming collects sounds from all directions and the sound is reproduced from the driver by performing blind spot beat-free (BF). For example, by setting a function to enable BF while walking, users can feel safe going out while wearing headphones. Furthermore, when walking stops, for example, the BF function is deactivated and noise cancellation is automatically activated. Therefore, in noise cancellation mode, users can immerse themselves in music or other sounds reproduced by the headphones.

[0365] Figure 31 This is a diagram illustrating the configuration of an acoustic output device according to the sixth embodiment using a transfer function. It should be noted that... Figure 31 A block diagram shows the transfer function of the beamforming-related portion of housing 520R. Furthermore, in Figure 31 In the process, beamforming can be used to enhance the corresponding noise 201, 202, ..., and 20 from directions "1", "2", ..., and "Q". Q .

[0366] FF microphone 1001 via space 180 11 180 21 ... and 180 Q1 Collect items with characteristics “N1”, “N2”, and “N” respectively. Q The noise levels 201, 202, ..., and 20 Q Among them, space 180 11 180 21 ... and 180 Q1 These are the space transfer functions X 11 X 21 ... and X Q1 FF microphone 1002 via space 180 12 180 22 ... and 180 Q2 Collect noise 201, 202, ..., and 20 Q 180 spaces 12 180 22 ... and 180 Q2 These are the space transfer functions X 12 X 22 ... and X Q2 Subsequently, similarly, the FF microphone 100 J via space 180 1J 180 2J , ... and 180 QJ Collect noise 201, 202, ..., and 20Q 180 spaces 1J 180 2J , ... and 180 QJ These are the space transfer functions X 1J X 2J , ..., and X QJ .

[0367] From FF microphones 1001, 1002, ..., and 100 J The output audio signals are respectively input to microphone amplifiers 1101, 1102, ..., and 110. J Here, there is an FF microphone 1001 and microphone amplifier 1101, an FF microphone 1002 and microphone amplifier 1102, ..., and an FF microphone 100 J and microphone amplifier 110 J They have transfer functions M1, M2, ..., and M respectively. J .

[0368] From microphone amplifiers 1101, 1102, ..., and 110 J The output sound signals are respectively input into the transfer function b 11 To b J1 b 12 To b J2 ... and b 1Q To b JQ BF filter 330 11 Up to 330 J1 330 12 Up to 330 J2 ... and 330 1Q Up to 330 JQ These blind spot BF filters 330 11 Up to 330 J1 330 12 Up to 330 J2 ... and 330 1Q Up to 330 JQ Included Figure 30B In the blind spot BF filter 330.

[0369] More specifically, the output of microphone amplifier 1101 is input to blind spot BF filter 330. 11 330 12 ... and 330 1Q The output of microphone amplifier 1102 is input to blind spot BF filter 330. 21 330 22 ... and 330 2QSimilarly, in the following text, microphone amplifier 110 J The output is input to the blind spot BF filter 330. J1 330 J2 ... and 330 JQ .

[0370] BF filter 330 11 330 21 ... and 330 J1 The generated noise-enhanced signal is synthesized by adder 1671 and input to localization filter 331. 11 331 12 ... and 331 1L Positioning filter 331 11 331 12 ... and 331 1L It is the transfer function w 11 w 12 ... and w 1L BF filter 330 with blind spot 12 330 22 ... and 330 J2 The generated noise-enhanced signal is synthesized by adder 1672 and input to localization filter 331. 21 331 22 ... and 331 2L Positioning filter 331 21 331 22 ... and 331 2L It is the transfer function w 21 w 22 ... and w 2L Similarly, the blind spot BF filter 330 1Q 330 2Q ... and 330 JQ The generated noise enhancement signal is generated by adder 167 Q The synthesized material is then input into the localization filter 331. Q1 331 Q2 ... and 331 QL Positioning filter 331 Q1 331 Q2 ... and 331 QL It is the transfer function w Q1 w Q2 ... and w QL .

[0371] It should be noted that the positioning filter 331 11 331 21 ... and 331QL Included Figure 30B The positioning filter 331 in the middle.

[0372] From positioning filter 331 11 331 21 ... 331 Q1 The output noise enhancement signal is synthesized by adder 1681 and the positioning is adjusted. From positioning filter 331 12 331 22 ... 331 Q2 The output noise enhancement signal is synthesized by adder 1682 and its positioning is adjusted. Similarly, through adder 168... L Synthesized from localization filter 331 1L 331 2L ... and 331 QL The output noise enhancement signal is then used to adjust the positioning. The level of the noise enhancement signal with adjusted positioning is determined by factors including... Figure 30B The corresponding horizontal control units 3321, 3322, ..., and 332 in the horizontal control unit 332. L Adjustment. This is achieved by horizontal control units 3321, 3322, ..., and 332. L The leveled noise enhancement signal is provided to drive amplifiers 1301, 1302, ..., and 130 L And respectively driven by drivers 1401, 1402, ... and 140 L It is reproduced as noise-enhanced sound.

[0373] Drives 1401, 1402, ..., and 140 L The reproduced noise enhancement signals are transmitted through the addition unit 160 in the housing 520R via spaces 231, 232, ..., 23 in the housing 520R. L (representing the spatial transfer functions G1, G2, ..., and G...) L The sound pressure 150, which is the sound pressure p, is synthesized and reaches the position of the eardrum 61.

[0374] The noise cancellation processing described in the first to fourth embodiments can be performed independently of the noise enhancement processing according to the sixth embodiment. For example, by combining the noise cancellation processing according to the reference... Figure 14 The configuration of the noise cancellation method of the second embodiment of the multi-microphone / multi-driver FF method described herein and Figure 31 The configuration shown can eliminate noise from sources other than the blind spot and reproduce noise in the direction of the blind spot, ensuring safety when users use the headphones outdoors.

[0375] (7-1. A variation of the sixth embodiment)

[0376] Next, a variation of the sixth embodiment will be described. The modification of the sixth embodiment is that it performs enhancement of the user's voice sound formed by beamforming using multiple FF microphones and location enhancement of the dialogue counterpart who is communicating with the user via multiple drivers.

[0377] In recent years, with the widespread adoption of video conferencing and voice call applications, remote work from home has become a reality. When holding voice conferences with multiple participants while working remotely, headsets are often used, consisting of a microphone located at the mouth and a driver worn on one of the left or right ears. In these typical headsets, because the speaker's voice signal is reproduced from a single driver, it can be difficult to instantly determine who is currently speaking. In such cases, the meeting may be disrupted or statements may be missed. Furthermore, because the microphone that collects the spoken voice signal is located at the mouth, the user wearing the microphone may experience pressure.

[0378] Therefore, in a variation of the sixth embodiment, by using a multi-microphone / multi-driver headset, the speech signals from multiple speakers are configured to resemble the target sound source and reproduced from the corresponding drivers. This makes it easy to immediately determine who is speaking. Furthermore, by using beamforming of the multi-microphones to direct the beam towards the user's mouth, the speech emitted by the user can be clearly collected.

[0379] Figure 32 This is a schematic diagram illustrating a voice call according to a variation of the sixth embodiment. Figure 32 In this example, headphones 53 are used (i.e., multi-microphone / multi-driver FF method noise cancellation headphones). It is important to note that this assumes... Figure 32 The earphone 53 shown has drivers further mounted in front and rear positions within the housing 520 when viewed from the user's perspective (not shown). Furthermore, in the following description, another user who communicates with the user, such as the user wearing the earphone 53, is referred to as the speaker.

[0380] Figure 32 Part (a) schematically illustrates an example, wherein, by using, for example, FF microphones 1001 and 100 J Beamforming 81, directed towards the user's mouth, enhances the speech signal generated by the user. This beamforming 81 towards the user's mouth is referred to as mouth beamforming (BF).

[0381] on the other hand, Figure 32Parts (b) and (c) schematically illustrate an example of controlling the location of a speaker's voice in a conversation via communication. Part (b) is an example of reproducing the speaker A's spoken voice through a driver 1401 located on the central portion of the housing 520 on the user's right side. The reproduced sound 82 from the driver 1401 reaches the position of the eardrum 61. Furthermore, for example, by controlling all the drivers located on the housings 520 of both ears, the speaker A's spoken voice can be heard from in front of the user.

[0382] Part (c) is the driver 1401 and 140 via the housing 520 on the user's right side. L An example of reproducing speaker B's voice during a conversation. Powered by drivers 1401 and 140... L The reproduced sound 83 is synthesized in the space within the housing 520 and reaches the position of the eardrum 61. For example, the volume and phase of the reproduced sound reproduced by the respective drivers located on each of the left and right housings 520 of the user's earphone 53 are controlled to predetermined values ​​so that the speaker B's voice can be heard from the user's right front.

[0383] Figure 33A This is a schematic diagram illustrating an example configuration of an acoustic output device according to a variation of the sixth embodiment. Figure 33A The configuration shown is the same as described above. Figure 30A The difference in the configuration shown is that DSP 300h is used instead of DSP 300g, and the speaker's voice signal 720 (instead of audio signal 700) emitted by the user wearing headphones 53 is input to DSP 300h.

[0384] Figure 33B This is a block diagram showing the configuration of an example of a modified DSP 300h according to the sixth embodiment. Figure 33B The configuration of the DSP 300h shown in the figure is similar to... Figure 30B The difference in the configuration of the DSP 300g shown is that the mouth BF filter 333 and EQ 334 are used instead of the blind spot BF filter 330 and the localization filter 331, and a speech source setting filter 335 is also used. Furthermore, in Figure 33B The configuration of the DSP 300h shown differs from that of the DSP 300g in that the output of the horizontal control unit 332 is provided to the control unit 310 instead of the adder 314.

[0385] In addition, Figure 33BIn the DSP 300h shown, the communication unit 212 is connected to the control unit 310. Under the control of the control unit 310, the communication unit 212 communicates with external devices via wireless or wired communication. Bluetooth (registered trademark) and the like can be used for wireless communication. For wired communication, communication via a Universal Serial Bus (USB) cable or the like is considered.

[0386] exist Figure 33B For example, speaker voice signal 720 is a voice signal acquired from speakers A and B, etc., through communication via communication unit 212. Speaker voice signal 720 is input to speech source setting filter 335. For example, the user operates operation unit 211 to instruct on speech source settings for determining where the speaker of the communicating party can be heard speaking. In response to this instruction, control unit 310 reads the filter coefficients adjusted from memory 210 to appear as if the speaker's speech can be heard from the indicated location, and writes the filter coefficients into speech source setting filter 335.

[0387] The localization of the speaker's voice signal 720 is set by the speech source setting filter 335, whose filter coefficients are written in this manner, and the speaker's voice signal is transmitted to the adder 314 via the EQ 311 and the level control unit 312.

[0388] The mouth BF filter 333 has a function equivalent to the aforementioned blind spot BF filter 330. That is, the mouth BF filter 333 performs beamforming based on a speech signal, which is based on the FF microphones 1001, 1002, ..., and 100 of the left and right housings 520. J The collected audio signal is input from the ADC 200a, and the speech signal is selectively acquired based on the sound from the mouth of the user wearing headphones 53. The speech signal output from the mouth BF filter 333 is adjusted for sound quality by the EQ 334 and transmitted to the control unit 310 via the level control unit 332. For example, the control unit 310 transmits the speech signal from the level control unit 332 to a playback device on the other side via communication unit 212. For example, the EQ 334 enhances the frequency band of human speech and cuts off additional frequency bands such as low and high frequencies.

[0389] Adder 314 synthesizes from elimination control unit 321 FF The noise cancellation signal and the speaker's voice signal 720 transmitted from the level control unit 312 are used to output the synthesized signal to the DAC 201.

[0390] As described above, in a variation of the sixth embodiment, noise cancellation via the FF method can simultaneously perform beamforming to acquire the user's speech and reproduce the speaker's speech signal 720, the arrangement of which is appropriately configured by the speech source setting filter 335. Therefore, the speech signals of speakers A and B can be focused, making it easy to hear their speech.

[0391] [8. Seventh Embodiment]

[0392] Next, a seventh embodiment of this disclosure will be described. The seventh embodiment is an example of correcting individual differences of the user wearing the headphones in a headset in which multiple drivers and multiple FB microphones are provided within the housing 520.

[0393] More specifically, in the acoustic characteristics within the housing while the user is wearing the headphones, the sound reproduced by the corresponding driver is collected by the corresponding FB microphone, and the acoustic characteristics (intra-auricular characteristics) within the housing are measured based on the collected sound. Then, various parameters affecting the intra-auricular characteristics are corrected based on the measurement results.

[0394] For example, in the case of noise cancellation using a multi-microphone / multi-driver FB method, it can be seen from the above expression (11) that in noise cancellation using an FB microphone, the transfer function H from the driver to the FB microphone position contributes to the cancellation performance. The transfer function H typically differs between the design of the FBNC filter and the actual use of the FBNC filter by the user. Furthermore, it varies depending on individual user differences and headphone wearing conditions. Therefore, it is difficult to provide noise cancellation using the optimal FB method.

[0395] Therefore, the in-ear characteristics T of each user can be measured by placing multiple microphones inside the earphone housing and reproducing the measurement signals from the corresponding drivers. The measurement signals used here can include sine waves, random noise, music signals, time-stretched pulse (TSP) signals, etc.

[0396] Figure 34 This is a schematic diagram illustrating an example of a method for measuring in-ear characteristics T according to the seventh embodiment. Here, the earphone 54 will be described as an example, which includes a plurality (in this case, three) of drivers 1401, 1402 and 1403 inside the housing 520. L And relative to Figure 18 The drives 1401, 1402 and 140 shown are L Multiple (in this example, three) FB microphones 1011, 1012, and 101 are located inside the housing 520. K .

[0397] In addition, Figure 34 For the sake of illustration, drive 1402 will be referred to as drive #1, drive 1401 as drive #2, and drive 140... L This is referred to as driver #3. For the sake of illustration, FB microphone 1011 is referred to as FB microphone #2, FB microphone 1012 is referred to as FB microphone #1, and FB microphone 101... K It is known as the FB microphone #3.

[0398] For example, such as Figure 34 As shown in part (a), firstly, the measurement signal is reproduced by driver #1, the reproduced sound is collected by FB microphones #1, #2 and #3, and the in-ear characteristics T are measured based on the collected sound. 11 T 12 and T 13 Next, as shown in section (b), the measured sound is reproduced via driver #2, the reproduced sound is collected via FB microphones #1, #2, and #3, and the in-ear characteristics T are measured based on the collected sound. 21 T 22 And T 23 Finally, as shown in section (c), the measured sound is reproduced by driver #3, the reproduced sound is collected by FB microphones #1, #2, and #3, and the in-ear characteristics T are measured based on the collected sound. 31 T 32 And T 33 .

[0399] As described above, when the three drivers #1, #2, and #3 and the three FB microphones #1, #2, and #3 are arranged in the housing 520, the in-ear characteristics T between nine points can be measured by combination. 11 To T 13 Intraocular characteristics T 21 To T 23 and the characteristics of the inner ear T 31 To T 33 Individual differences caused by users wearing headphones (53%) can be corrected by adjusting for in-ear characteristics (T). 11 To T 13 T 21 To T 23 and the characteristics of the inner ear T 31 To T 33 To correct for the transfer function H when designing the FBNC filter 320c.

[0400] Figure 35 This is a schematic diagram illustrating the configuration of an example of an acoustic output device according to the seventh embodiment. Since, apart from the DSP 300i, Figure 35 The configuration shown is the same as described above. Figure 19A Since the configurations are the same, descriptions of units other than the DSP 300i will be omitted.

[0401] It should be noted that, Figure 35 In this section, the portion related to the measurement depth of the in-ear characteristic T is extracted and shown, and the configuration related to the reproduction of the audio signal 700, etc., is appropriately omitted. That is, the DSP 300i includes, for example, in Figure 19B The FBNC filter 320c and the cancellation control unit 321 shown are... FB In addition, the DSP 300i also includes, for example, Figure 19B The EQ 311 and horizontal control unit 312 are shown.

[0402] In addition, the memory 210, the operation unit 211, and the communication unit 212 are connected to the DSP 300i.

[0403] The DSP 300i includes a control unit 310, a measurement signal generation unit 340, a level control unit 312, a measurement data acquisition unit 350, a correction value calculation unit 351, and an FBNC filter correction unit 352.

[0404] The measurement signal generation unit 340 generates a measurement signal for measuring the in-ear characteristic T. As described above, sine waves, random noise, music signals, TSP signals, etc., can be used as measurement signals. For example, the control unit 310 instructs the measurement signal generation unit 340 to generate and output a measurement signal based on a user operation on the operation unit 211. The measurement signal generation unit 340 generates and outputs the measurement signal according to this instruction. The measurement signal generation unit 340 reads, for example, measurement signal information used to generate the measurement signal (such as waveform data pre-stored in the memory 210) to generate the measurement signal.

[0405] The level control unit 312 adjusts the measurement signal output from the measurement signal generation unit 340 to a predetermined level and transmits it to the DAC 201. The DAC 201 converts the transmitted digital measurement signal into an analog measurement signal and supplies the analog measurement signal to the drive amplifiers 1301, 1302, and 103. L Each of them. Drive amplifiers 1301, 1302, and 130. L Drive drivers 1401, 1402 and 140 respectively L To reproduce the measurement signal.

[0406] At this time, the control unit 310 can control, for example, drive amplifiers 1301, 1302, and 130 L Select which driver (1401, 1402, or 140) the measurement signal is fed to. L Reappearance.

[0407] By drive 1401, 1402 or 140 L The measurement sound obtained by reproducing the measurement signal is obtained by FB microphones 1011, 1012 and 101. K The collected and measured sound signals are transmitted via microphone amplifiers 1111, 1112, and 111. K The input is ADC 200b. ADC 200b will draw inputs from microphone amplifiers 1111, 1112, and 111. K Each input measurement sound signal is converted into a digital measurement sound signal to output a digital measurement sound signal.

[0408] Each measured sound signal output from ADC 200b is acquired by measurement data acquisition unit 350 and transmitted to correction value calculation unit 351. Correction value calculation unit 351 obtains an in-ear characteristic T based on each measured sound signal acquired by measurement data acquisition unit 350. Based on the obtained in-ear characteristic T, correction value calculation unit 351 calculates an FBNC filter correction value for correcting FBNC filter 320c (not shown). For example, correction value calculation unit 351 calculates the correction value for... Figure 21 The FBNC filter 121 shown 11 Up to 121 KL Filter coefficients -β 11 to -β KL The FBNC filter correction value is calculated and then transmitted to the FBNC filter correction unit 352.

[0409] The FBNC filter correction unit 352 corrects various parameters of the FBNC filter 320c, such as the filter coefficient -β, based on the FBNC filter correction value transmitted from the correction value calculation unit 351. Each parameter of the corrected FBNC filter 320c is stored in the memory 210 via the control unit 310.

[0410] The memory 210 can store multiple parameters of the FBNC filter 320c. For example, measurements can be performed for each user using the headphones 53 or for each user's usage environment (location of use, presence or absence of hats or glasses, hairstyle, etc.), and the parameters can be stored. The user can specify the parameters according to the situation when using the headphones 53 through user operation on the operation unit 211. The control unit 310 writes the specified parameters into the FBNC filter 320c.

[0411] Figure 36This is a flowchart illustrating an example of the measurement process according to the seventh embodiment. For example, when the control unit 310 issues a measurement start command, in step S100, the measurement signal generation unit 340 reads measurement signal information from the memory 210. In the next step S101, the measurement signal generation unit 340 generates a measurement signal based on the measurement signal information read in step S100.

[0412] In the next step S102, the measurement signal generation unit 340 outputs the measurement signal generated in step S101. The measurement signal output from the measurement signal generation unit 340 is provided to the drive amplifiers 1301, 1302, and 1303 via the level control unit 312 and the DAC 201. L And it is reproduced as a measured sound signal.

[0413] In the next step S103, FB microphones 1011, 1012 and 101 K The collection is achieved by driving amplifiers 1301, 1302, or 130. L The measured sound is obtained by reproducing the measured sound signal. Based on FB microphones 1011, 1012, and 101... K The collected measurement sound signal is acquired by the measurement data acquisition unit 350 and transmitted to the correction value calculation unit 351.

[0414] In step S104, the correction value calculation unit 351 calculates the in-ear characteristic T based on each measured sound signal transmitted from the measurement data acquisition unit 350. lk Here, the intraocular characteristic T lk From drives 1401, 1402 and 140 L The first driver in the series connects to FB microphones 1011, 1012, and 101. K The transfer function of the k-th FB microphone in the array. For example, in drivers 1401, 1402, and 140... L While switching the driver that reproduces the measured sound, the above steps S102 to S104 are repeatedly performed.

[0415] When using drives 1401, 1402 and 140 L With FB microphones 1011, 1012 and 101 k The combined measurements were completed and the intraocular characteristic T for each ear was calculated. lk At this point, the processing proceeds to step S105. In step S105, the control unit 310 calculates each intra-auricular characteristic T based on the correction value calculation unit 351 calculated in step S104. lkCalculate the FBNC filter correction value for calibrating the FBNC filter 320c, and store each parameter of the FBNC filter 320c corrected by the calculated FBNC filter correction value in the memory 210.

[0416] As described above, in the seventh embodiment, a plurality of drivers 1401, 1402, and 1403 disposed in the housing 520 are used. L And multiple Facebook microphones 1011, 1012 and 101 K The in-ear characteristic T is calculated, and each parameter of the FBNC filter 320c is corrected based on the calculation results. Therefore, the performance of noise cancellation by the FB method can be improved.

[0417] (8-1. First variation of the seventh embodiment)

[0418] Next, a first variation of the seventh embodiment will be described. The first variation of the seventh embodiment differs from the seventh embodiment described above in that it uses an equalizer for correcting the sound signal based on the measured intraocular characteristics T.

[0419] Figure 37 This is a schematic diagram illustrating the configuration of an example of an acoustic output device according to a first variation of the seventh embodiment. Since, in addition to the DSP 300j, in... Figure 37 The configuration shown is the same as described above. Figure 35 Since the configurations are the same, descriptions of units other than DSP 300j will be omitted.

[0420] It should be noted that, Figure 37 In this section, the portion related to the measurement depth of the intraocular characteristic T is extracted and shown, and the configuration related to the reproduction of the audio signal 700, etc., is appropriately omitted. That is, the DSP 300j includes, for example, in Figure 19B The FBNC filter 320c and the cancellation control unit 321 shown are... FB Furthermore, the DSP 300j further includes, for example, Figure 19B The EQ 311 and horizontal control unit 312 are shown.

[0421] exist Figure 37 The difference between DSP 300j and DSP 300i mentioned above is the addition of a reproduction EQ correction unit 353. The correction value calculation unit 351 calculates the FBNC filter correction value for correcting the FBNC filter 320c (not shown) based on each measured sound signal acquired by the measurement data acquisition unit 350, and calculates the EQ correction value for correcting EQ 311 (not shown).

[0422] The EQ correction value calculated by the correction value calculation unit 351 is passed to the reproduction EQ correction unit 353. The reproduction EQ correction unit 353 corrects the parameters of EQ 311 (not shown) based on the passed EQ correction value. The corrected parameters of EQ 311 are stored, for example, in memory 210.

[0423] As described above, by correcting each parameter of the EQ 311 for the audio signal 700 based on measured in-ear characteristics T, the characteristics of the audio signal 700 reproduced by the headphones 54 can be optimized according to individual characteristics (ear shape, etc.). Therefore, for example, in the low-frequency correction of the audio signal 700, the effect of improving sound quality according to individual differences or individual wearing conditions can be expected.

[0424] (8-2. Second variation of the seventh embodiment)

[0425] Next, a second variation of the seventh embodiment will be described. The second variation of the seventh embodiment is in which a plurality of drivers 1401 to 140... L and multiple FB microphones 1011 to 101 K Settings Figure 22 An example of the interior of housing 520 is shown, and in headset 55, multiple FF microphones 1001 to 100 are included. J With the external orientation of housing 520, the parameters of FBNC filter 320c and EQ311 are corrected, and the parameters of FFNC filter 320b are corrected.

[0426] Figure 38 This is a schematic diagram illustrating the configuration of an example of an acoustic output device according to a second variation of the seventh embodiment. Figure 38 To avoid complexity, the multiple FF microphones 1001 to 100 included in the headset 55 are not shown. J .

[0427] By drive 1401, 1402 or 140 L The measurement sound obtained by reproducing the measurement signal is obtained by FB microphones 1011, 1012 and 101. K The collected and measured sound signals are transmitted via microphone amplifiers 1111, 1112, and 111. K The input is ADC 200b. ADC 200b will draw inputs from microphone amplifiers 1111, 1112, and 111. K Each input measurement sound signal is converted into a digital measurement sound signal to output a digital measurement sound signal.

[0428] Each measured sound signal output from ADC 200b is input to DSP 300k, acquired by measurement data acquisition unit 350, and transmitted to correction value calculation unit 351. Correction value calculation unit 351 obtains the in-ear characteristic T based on each measured sound signal acquired by measurement data acquisition unit 350. Based on the obtained in-ear characteristic T, correction value calculation unit 351 calculates FBNC filter correction values ​​for calibrating FBNC filter 320c (not shown) and FFNC filter correction values ​​for calibrating FFNC filter 320b (not shown). Correction value calculation unit 351 sends the calculated FBNC filter correction values ​​and FFNC filter correction values ​​to FF / FBNC filter correction unit 354.

[0429] The FF / FBNC filter correction unit 354 corrects the parameters of the filter coefficient -β of an FBNC filter such as FBNC filter 320c based on the FBNC filter correction value transmitted from the correction value calculation unit 351. Additionally, the FF / FBNC filter correction unit 354 corrects the parameters of the filter coefficient α of an FFNC filter such as FFNC filter 320b based on the FFNC filter correction value transmitted from the correction value calculation unit 351. Each parameter of the corrected FFNC filter 320b and FBNC filter 320c is stored in the memory 210 via the control unit 310.

[0430] Here, as can be seen from the above expression (2), noise cancellation via the FF method requires a spatial transfer function G from the driver to the eardrum position. This also applies to noise cancellation via the multi-driver FF method. The spatial transfer function G in the design of the FFNC filter 320b differs from the spatial transfer function G in the actual state when the headphones are worn by the user. Furthermore, the shape of the ear varies among users, causing the spatial transfer function G to vary. This makes it difficult to provide optimal cancellation performance to the user.

[0431] For reference Figure 34 As described, in the three drives 1401, 1402 and 140 L And three Facebook microphones: 1011, 1012, and 101. K With the device positioned inside housing 520, the user's intra-auricular characteristics T can be measured at nine points. By obtaining a correction coefficient C that minimizes the error between the intra-auricular characteristics T and the spatial transfer function G during the design of the FFNC filter as a reference intra-auricular characteristic, and reflecting the correction coefficient C in each parameter of the FFNC filter 320b, an improvement in elimination performance can be expected.

[0432] Figure 39This is a flowchart illustrating an example of the correction value calculation process according to a second variation of the seventh embodiment. In step S200, the correction value calculation unit 351, for example, reads a reference characteristic pre-stored in the memory 210. bar H lk It is important to note that, bar The symbol “~ (tilde)” is placed above the next character (in this case, “H”). Simultaneously, the correction value calculation unit 351 reads, for example, the intraocular characteristic T stored in memory 210 during a previous measurement from memory 210. lk .

[0433] The processes in steps S210 to S212, S220 to S222, and S230 to S232 can be executed in parallel or sequentially.

[0434] In step S210, the correction value calculation unit 351 calculates the correction value based on the reference characteristics. bar H lk and Intra-ear characteristics T lk The correction coefficients for each parameter of the FFNC filter 320b are calculated. The correction value calculation unit 351 processes the calculated correction coefficients C. FFlk The data is transmitted to the FF / FBNC filter correction unit 354. In the next step S211, the FF / FBNC filter correction unit 354 adjusts the data according to the correction coefficient C. FFlk The filter coefficient α of the FFNC filter 320b is updated. In the next step S212, the control unit 310 stores the updated filter coefficient α in the memory 210.

[0435] In step S220, the correction value calculation unit 351 calculates the correction value based on the reference characteristics. bar H lk and Intra-ear characteristics T lk Calculate the correction coefficient C for each parameter of the FBNC filter 320c. FBlk The correction value calculation unit 351 calculates the correction coefficient C. FBlk The signal is transmitted to the FF / FBNC filter correction unit 354. In the next step S221, the FF / FBNC filter correction unit 354, based on the correction coefficient C... FBlk The filter coefficient β of the FBNC filter 320c is updated. In the next step S222, the control unit 310 stores the updated filter coefficient β in the memory 210.

[0436] In step S230, the correction value calculation unit 351 calculates the correction value based on the reference characteristics. bar H lk and Intra-ear characteristics T lkCalculate the correction factor C for each parameter of EQ 311 used to correct the reproduction of audio signal 700. EQlk The correction value calculation unit 351 calculates the correction coefficient C. EQlk The data is transmitted to the reproduction EQ correction unit 353. In the next step S231, the reproduction EQ correction unit 353 adjusts the data based on the correction coefficient C. EQlk Update the parameters of EQ 311. In the next step S232, the control unit 310 stores the updated parameters of EQ 311 in the memory 210.

[0437] For example, when headphones 55 reproduce audio signal 700, control unit 310 applies the filter coefficients α and β stored in memory 210 and the parameters of EQ 311 to FFNC filter 320b, FBNC filter 320c, and EQ 311, respectively. Therefore, for example, a user wearing headphones 55 can listen to the reproduced sound of audio signal 700, wherein noise is eliminated while the user's characteristics are matched to the sound quality corrected according to the user's characteristics by EQ 311.

[0438] (8-3. Third variation of the seventh embodiment)

[0439] Next, a third variation of the seventh embodiment will be described. The third variation of the seventh embodiment is an example in which a plurality of drivers and a plurality of FB microphones are provided inside the housing 520 of the headphones, and the wearing state (referred to as wearing determination) is determined when the user wears the headphones.

[0440] Note that here, it is assumed that... Figure 35 The configuration shown is applied as a configuration for an acoustic output device, and a description is given.

[0441] In noise-canceling headphones, the fit of the headphones significantly affects the noise cancellation effect. For example, when the headphones have a poor fit and there is a large gap between the user's head 40 and the ear pads 510, external noise can leak through the gap, weakening the noise cancellation effect. As a simple example, based on the above... Figure 1 As shown in expression (2), the wearability of headphones is extremely important because it affects the leakage noise, which leaks from the driver into the headphone housing through the space transfer functions F and G, reaching the eardrum.

[0442] For example, in headphones 54, there are multiple drivers 1401 to 140. L and multiple FB microphones 1011 to 101 K Arranged in reference Figure 18 In the described housing 520, the actuators 1401 to 140 LReproduce the measurement signal. FB microphones 1011 to 101 K The measured sound was collected by reproducing the measurement signal and analyzed based on the data from FB microphones 1011 to 101. K The in-ear characteristics T calculated from the output measured sound signal lk This allows us to determine the details of the situation where the headphones 54 are worn.

[0443] Figure 40 This is a schematic diagram used to illustrate the wearing determination according to the third variation of the seventh embodiment. Figure 40 The example illustrates a state where the earphone 54, worn by a user on head 40, has poor fit and a gap forms between head 40 and the upper ear pad 510 of housing 520. In this state, the drivers 1401 to 140 of earphone 54... L The measurement signals are reproduced one by one, and FB microphones 1011 to 101 are used. K The measured sound obtained by reproducing the measurement signal is collected to detect the location of leaked noise.

[0444] exist Figure 40 For the sake of illustration, drive 1402 will be referred to as drive #1, drive 1401 as drive #2, and drive 140... L This is referred to as driver #3. For the sake of illustration, FB microphone 1011 is referred to as FB microphone #2, FB microphone 1012 is referred to as FB microphone #1, and FB microphone 101... K It is known as the FB microphone #3.

[0445] Figure 40 Part (a) shows an example of a measurement signal reproduced by driver #1. In this case, the reproduced measurement sound leaks in the opposite direction to the wavefront direction of the measurement sound from driver #1. When analyzing the low-frequency power of the measurement sounds collected by each of FB microphones #1 to #3, it is found that the power p from driver #1 to FB microphone #3 is... 13 Maximum, and power p from driver #1 to FB microphone #1 11 Minimum. Power p from driver #1 to FB microphone #2 12 Between these two power levels.

[0446] Section (b) illustrates an example of the measurement signal being reproduced by driver #2. In this case, the reproduced measurement sound leaks obliquely upward relative to the wavefront direction of the measurement sound from driver #2. When analyzing the low-frequency power of the measurement sounds collected by each of FB microphones #1 to #3, it was found that the power p from driver #2 to FB microphone #3... 23Maximum, and power p from driver #2 to FB microphone #1 21 Minimum. Power p from driver #2 to FB microphone #2 22 Between these two power levels.

[0447] Section (c) illustrates an example of a measurement signal reproduced by driver #3. In this case, the reproduced measurement sound leaks upwards in the wavefront direction of the measurement sound relative to driver #3. When analyzing the low-frequency power of the measurement sounds collected by each of FB microphones #1 to #3, it is found that the power p from driver #3 to FB microphone #3 is significantly higher. 33 Maximum, and power p from driver #3 to FB microphone #1 31 Minimum. Power P from driver #3 to FB microphone #2 32 It lies between these two power levels.

[0448] As can be seen from the above, the power p from driver #1 to FB microphone #1 11 Power p from driver #2 to FB microphone #1 21 And the power p from driver #3 to FB microphone #1 31 It is small, and it can be determined that the fit of the headphones 54 near the upper part of the ear is poor.

[0449] Figure 41A and Figure 41B This is a diagram illustrating an example of a notification method applicable to the eighth embodiment, which notifies the user wearing the earphone 54 of the state determined as described above.

[0450] Figure 41A An example is shown of using a portable terminal device 900, such as a smartphone or tablet PC, to notify the wearer of a determination result. For example, the terminal device 900 may have a pre-installed application corresponding to the determination result notification.

[0451] It should be noted that the general configuration of a communicable information processing device can be applied to terminal device 900, and the terminal device includes, for example, a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), storage devices such as flash memory, a communication interface (I / F) for performing wireless communication, an input device for receiving user operations, and a display device, and the CPU controls the entire operation according to a program stored in the storage device. Terminal device 900 is not limited to this and can also be a device dedicated to headset 54. The aforementioned application is provided, for example, from an external network via the communication I / F and is installed in terminal device 900.

[0452] The control unit 310 notifies the terminal device 900 of the determination result of the wearing status obtained as described above via communication unit 212. The terminal device 900 displays a screen for displaying the notification content on its display 901 via the aforementioned application. In this example, the state of the headphones being worn on the head is schematically shown in area 910 of the display 901, and the portion with an unsuitable wearing status is highlighted by a frame line 911. Furthermore, a message 912 specifically indicating which part of the wearing status is unsuitable ("The wearing condition above the ear appears to be poor") is further displayed on the display 901.

[0453] Note that in this example, buttons 920 and 921 are arranged at the bottom of the display 901. Button 920 is, for example, a button used to end the display of the determination result. Furthermore, button 921 is a button used to instruct the earphone 54 to perform a remeasurement to re-determine the wearing status. The terminal device 900 sends a remeasurement command to the earphone 54 in response to the operation of button 921. This command is received by the communication unit 212 in the earphone 54 and transmitted to the control unit 310. The control unit 310 controls each unit of the earphone 54 according to the transmitted command and performs the remeasurement and wearing determination.

[0454] Figure 41B This is an example of informing the wearer of a confirmed result through audio reproduced by headphones 54. Figure 41B In one instance, the driver 1401 reproduces the voice message 922 indicating the wearing result ("The wearing condition of the upper ear accessory appears to be poor").

[0455] For example, the control unit 310 generates a voice message 922 using voice data representing the determination result of the wearing state obtained as described above. For example, a message representing the hypothetical wearing determination result is pre-stored in the memory 210. The control unit 310 reads the message based on the determination result of the wearing state from the memory 210 using, for example, a known reading technique, converts the read message into voice data, and generates the voice message 922. The invention is not limited thereto; the message may be stored as voice data in the memory 210.

[0456] Control unit 310 provides the generated voice message 922 to drive amplifiers 1301 to 1301 via DAC 201. L Each of them, and make drive 1401 to 140 L Reproduce the voice message. In this case, voice message 922 can be reproduced by drivers 1401 to 140. L At least one of them can be reproduced. It can also be from drive 1401 to 140. L The driver, located near the position determined to be in poor wearing condition, reproduces voice message 922.

[0457] Here, with only one FB microphone installed in the housing 520, it is difficult to identify parts with poor wearing conditions. In the third variation of the seventh embodiment, because multiple FB microphones 1011 to 101... K It is located in the housing 520, so the wearing status can be determined in detail.

[0458] [9. Eighth Implementation]

[0459] Next, an eighth embodiment of this disclosure will be described. The eighth embodiment is an example where the function of each of the above embodiments can be configured into an operation mode based on user operation.

[0460] Among the functions described in each embodiment, the functions that can be set to the operation mode are as follows.

[0461] (1) Noise cancellation function via FF method, FB method or dual method. These functions correspond to the first to fourth embodiments.

[0462] (2) A function that reproduces highly realistic sounds using 3D audio signals (object sound sources). This function corresponds to the fifth embodiment and can be implemented using multi-driver headphones.

[0463] (3) Sound collection and reproduction function for noise in a specific direction. This is a function corresponding to the sixth embodiment and can be implemented by a multi-FF microphone / multi-driver headset.

[0464] (4) The beamforming function of the mouth is a function corresponding to the variation of the sixth embodiment, and it is a function that can be implemented by a multi-FF microphone / multi-driver headset.

[0465] (5) The beamforming function on the blind spot is a function corresponding to the sixth embodiment, and it is a function that can be implemented by a multi-FF microphone / multi-driver headset.

[0466] (6) Function to correct for individual differences during wear. This is a function corresponding to the seventh embodiment and its first and second modifications, and is a function that can be achieved with a multi-FB microphone / multi-driver headset.

[0467] (7) Wearing confirmation function. This is a function corresponding to the third variation of the seventh embodiment, and it is a function that can be implemented by a multi-FB microphone / multi-driver headset.

[0468] Figure 42 This is a schematic diagram illustrating an example configuration of an acoustic output device according to the eighth embodiment. Figure 42 The configuration shown is capable of performing each of the functions (1) through (7) described above. (See reference...) Figure 22 The description includes headphones 55 and multiple FF microphones 1001 to 100. J The external portion of the housing 520 is provided, and multiple drives 1401 to 140 are arranged thereon. L and multiple FB microphones 1011 to 101 K It is located inside the housing 520.

[0469] Figure 42 Together they show corresponding to FF microphones 1001 to 100 respectively. J Microphone amplifiers 1101 to 110J serve as microphone amplifier 110 and correspond to FB microphones 1011 to 101 respectively. K Microphone amplifier 1111 to 111 K As a microphone amplifier 111. Similarly, the figure collectively shows drivers 1401 to 140 respectively. L The drive amplifiers 1301 to 130 L As a driver amplifier 130.

[0470] The ADC 200d converts each audio signal provided by microphone amplifiers 110 and 111 into a digital audio signal and inputs the digital audio signal to the DSP 3001.

[0471] The DSP 3001 includes a control unit 310, an EQ 311, a level control unit 312, a measurement signal generation unit 340, a filter unit 360, a correction processing unit 361, and an adder 313.

[0472] The filter unit 360 includes the aforementioned filters (FFNC filter 320b, FBNC filter 320c, blind spot BF filter 330, positioning filter 331, and mouth BF filter 333). Furthermore, the filter unit 360 includes an EQ 334, a level control unit 332, and a cancellation amount control unit 321. FF 321 FB Furthermore, the filter unit 360 includes a positioning filter 170 for positioning the target sound source 710. Under the control of the control unit 310, the filter unit 360 can be configured independently or in a predetermined combination of these functions.

[0473] The calibration processing unit 361 includes a measurement data acquisition unit 350, a calibration value calculation unit 351, an FF / FBNC filter calibration unit 354, and a reproducible EQ calibration unit 353. Under the control of the control unit 310, the calibration processing unit 361 can be configured by these functions individually or in a predetermined combination.

[0474] Here, a portion of the EQ 311, the level control unit 312, and the filter unit 360 (e.g., the positioning filter 170) performs the function of reproducing the audio signal and processes the input signal 730, which includes the audio signal 700, the object sound source 710, and the speaker's voice signal 720.

[0475] In the eighth embodiment, the above-mentioned functions (1) to (7) can be set from a terminal device 900 that can communicate with the communication unit 212. Figure 43 This is a schematic diagram illustrating an example of a function setting screen that can be applied to the eighth embodiment and is displayed on the display 901 of the terminal device 900. The function setting screen is displayed on the display 901 when an application installed on the terminal device 900 is executed.

[0476] exist Figure 43 In the display 901, area 930 is used to perform settings, noise cancellation, etc., when reproducing the audio signal 700 or the object sound source 710 through the headphones 55. Furthermore, area 931 is used to perform measurement processing using measurement signals in the headphones 55.

[0477] exist Figure 43 In this example, checkboxes 930a to 930e are provided in region 930. Input is performed on these checkboxes 930a to 930e by adding a return marker to the box. Adding a return marker to checkbox 930a sets the execution of noise cancellation using the FF method. Adding a return marker to checkbox 930b sets the execution of noise cancellation using the FB method. Adding a return marker to checkbox 930c sets the reproduction of the 3D audio signal (object sound source 710). Adding a return marker to checkbox 930d sets the execution of mouth beamforming (BF). Additionally, adding a return marker to checkbox 930e sets the execution of blind spot beamforming (BF). Multiple return markers can be added to checkboxes 930a to 930e simultaneously.

[0478] Additionally, buttons 931a and 931b are provided in area 931 for inputting information according to operation. Button 931a is used to instruct the user to perform correction for individual differences according to the seventh embodiment or the first and second variations of the seventh embodiment. In response to the operation of button 931a, the measured sound signal is reproduced in the earphone 55, and the measurement of the in-ear characteristic T begins. Button 931b is used to instruct the wearing determination of the earphone 55 according to the third variation of the seventh embodiment. In response to the operation of button 931b, the measured sound signal is reproduced in the earphone 55, and the reproduced sound leakage to the outside of the housing 520 is measured.

[0479] Terminal device 900 sends instructions to headset 55 corresponding to inputs to checkboxes 930a to 930e and operations of buttons 931a and 931b. In headset 55, these instructions are received by communication unit 212 and transmitted to control unit 310. Control unit 310 controls filter unit 360, measurement signal generation unit 340, correction processing unit 361, etc., according to the transmitted instructions, to cause them to execute the instructions.

[0480] As described above, in the eighth embodiment, since the execution of each function in the headset 55 can be instructed from the terminal device 900, the user can easily set the individual functions of the headset 55 to be executed independently or in combination.

[0481] [10. Ninth Implementation]

[0482] Next, a ninth embodiment of this disclosure will be described. The ninth embodiment is an example in which a plurality of drivers 1401 to 140 are disposed inside the housing 520 of an earphone. L Drives 1401 to 140 L One or more of them are operated and used as microphones.

[0483] It is known that dynamic drivers (loudspeakers) can be used as microphones. This is because the electrical, vibrational, and sound radiation mechanisms of dynamic drivers are simply the opposite of those of microphones, which involve sound incidence, vibration, and electrical processes.

[0484] Figure 44A and Figure 44B This is a schematic diagram illustrating an example of a driver according to the ninth embodiment being used as a microphone.

[0485] Figure 44A This is a schematic diagram of a vertical cross-section illustrating the appearance of an example of a multi-driver headphone that can be applied to the ninth embodiment and has multiple drivers disposed inside the housing 520. Figure 44A The earphone 57 shown has multiple (three in this example) drivers 1401, 1402 and 1403 arranged inside the housing 520.

[0486] It should be noted that, for the sake of explanation, Figure 44A and Figure 44B Driver 1401 as driver #1, driver 1402 as driver #2, and driver 1403 as driver #3 are shown.

[0487] Figure 44BThis is a schematic diagram illustrating an example of three drivers 1401 to 1403 disposed in housing 520, one of which functions as a driver (speaker) with its original function, and the other two as microphones. In this case, for example, the measurement signal is reproduced by the driver that functions as the original function, and the measurement sound obtained by reproducing the measurement signal is collected by the two drivers that function as microphones.

[0488] exist Figure 44B In part (a), the measurement signal is reproduced by driver #1, and the reproduced measurement sound is collected using drivers #2 and #3 as microphones. Based on the measurement sound signal obtained by collecting the measurement sound by drivers #2 and #3, the intraocular characteristic T from driver #1 to driver #2 can be calculated. 12 and the in-ear characteristics T from driver #1 to driver #3 13 .

[0489] exist Figure 44B In part (b), the measurement signal is reproduced by driver #2, and the reproduced measurement sound is collected by drivers #1 and #3, which act as microphones. Based on the measurement sound signal obtained by collecting the measurement sound through drivers #1 and #3, the intraocular characteristic T from driver #2 to driver #1 can be calculated. 21 and the in-ear characteristics T from driver #2 to driver #3 23 .

[0490] In addition, Figure 44B In part (c), the measurement signal is reproduced by driver #3, and the reproduced measurement sound is collected by drivers #1 and #2, which act as microphones. Based on the measurement sound signal obtained by collecting the measurement sound by drivers #1 and #2, the intraocular characteristic T from driver #3 to driver #1 can be calculated. 31 And the in-ear characteristics T from driver #3 to driver #2 32 .

[0491] Based on the calculated intraocular characteristics T 12 T 13 T 21 T 23 T 31 and T 32 For example, corrections for individual differences according to the seventh embodiment and its first and second modifications can be performed. Additionally, the wearing determination according to the third modification of the seventh embodiment can be performed by further measuring the power of the collected measurement sound.

[0492] Figure 45This is a flowchart illustrating an example of a process for measuring in-ear characteristics T using a driver as a microphone according to the ninth embodiment. The process according to this flowchart begins while the user is wearing headphones 57.

[0493] Note that here, L drivers are provided in the housing 520, and driver (I) refers to a driver selected sequentially from the L drivers in a loop. Whether a driver is used as a microphone is controlled by a driver amplifier corresponding to the driver, according to instructions from the control unit 310. Furthermore, the seventh embodiment will be described here... Figure 35 The configuration is applied as an acoustic output device. Furthermore, when the driver is used as a microphone, the signal output from the driver is collected via microphone amplifiers 1111 to 111. K And ADC 200b is provided to DSP 300i.

[0494] In step S300, the control unit 310 selects a driver (I) from the L drivers to be used for the original function. In the next step S301, the control unit 310 sets the drivers other than the driver (I) selected in step S300 from the L drivers to a microphone mode that can be used as a microphone.

[0495] In the next step S302, the control unit 310 instructs the measurement signal generation unit 340 to generate and output a measurement signal, and causes the driver (I) set in step S300 to reproduce the measurement signal. In the next step S303, the drivers other than driver (I) of the L drivers collect the measurement sounds obtained by reproducing the measurement signals through driver (I). Each measurement sound signal obtained by collecting and outputting measurement sounds by drivers other than driver (I) is provided to DSP 300i. DSP 300i calculates, for example, an intraocular characteristic T based on each provided measurement sound signal.

[0496] In the next step S304, the control unit 310 determines whether the sound collection of the reproduction of the measurement signal of the driver (l) and the reproduction of the measurement sound of the other driver has ended. When it is determined that they have not yet ended (step S304, "No"), the control unit 310 returns the process to step S302.

[0497] When it is determined that they have been completed (step S304, "Yes"), the control unit 310 moves the processing to step S305. In step S305, the control unit 310 performs fading processing on the measured sound obtained by reproducing the measured sound signal. For example, the control unit 310 causes the level control unit 312 to attenuate the level of the measured signal output from the measured signal generation unit 340 within a predetermined time, and fades out the reproduced sound. Therefore, sudden interruptions in the reproduced sound can be avoided, and discomfort to the user wearing the headphones 57 can be suppressed.

[0498] In the next step S306, the control unit 310 determines whether all drivers in the housing 520 have reproduced the measurement signal. When it is determined that all drivers in the housing 520 have reproduced the measurement signal (step S306, "Yes"), the control unit 310 terminates a series of processes according to the flowchart.

[0499] On the other hand, when it is determined that all drivers in the housing 520 have failed to reproduce the measurement signal, that is, there is a driver among the L drivers in the housing 520 that has failed to reproduce the measurement signal (step S306, "No"), the control unit 310 returns the process to step S300. Then, the control unit 310 selects the driver that reproduces the measurement signal (1) from the L drivers in the housing 520 that have failed to reproduce the measurement signal (step S300), and performs the process in and after step S301.

[0500] According to the ninth embodiment, some of the multiple drivers in the housing 520 are used as microphones to perform measurements such as intraocular characteristics T. Therefore, compared to the case where multiple microphones are provided in the housing 520, the space in the housing 520 can be reduced, resulting in a smaller headphone size. Furthermore, since multiple microphones are not provided in the housing 520, costs can be reduced.

[0501] Furthermore, the effects described in this identification are merely examples and are not limited, and other effects may exist.

[0502] This technology can also be configured as follows.

[0503] (1) An acoustic output device, comprising:

[0504] case;

[0505] One or more outward-facing microphones are disposed on the housing, facing outwards from the housing; and

[0506] Two or more drivers are disposed inside the housing, and each driver generates an acoustic control sound based on an acoustic control signal.

[0507] (2) The acoustic output device according to (1) above, wherein,

[0508] The two or more drives include a first drive and a second drive, wherein

[0509] The first driver is configured to cause the sound wave to be emitted to propagate in a first direction, and wherein

[0510] The second driver is configured to cause the sound wave to be emitted to propagate in a second direction different from the first direction.

[0511] (3) The acoustic output device according to (2) above further includes:

[0512] The signal processing unit generates the acoustic control signal, wherein

[0513] The signal processing unit includes a first filter that generates the acoustic control signal based on sound collected by a first microphone included in the one or more outward-facing microphones.

[0514] (4) The acoustic output device according to (3) above, wherein,

[0515] The signal processing unit

[0516] It further includes a second filter that generates the acoustic control signal based on sound collected by a second microphone included in the one or more outward-facing microphones.

[0517] (5) The acoustic output device according to (4) above, wherein,

[0518] The first microphone is mounted on the housing to collect upward-facing sound from a third party, and wherein...

[0519] The second microphone is configured to collect sound from a fourth direction, different from the third direction.

[0520] (6) The acoustic output device according to (5) above, wherein,

[0521] The signal processing unit

[0522] Based on the corresponding sounds collected by the first microphone and the second microphone, a first acoustic control signal for generating the acoustic control sound is generated for the first driver, and a second acoustic control signal for generating the acoustic control sound is generated for the second driver.

[0523] (7) The acoustic output device according to any one of (3) to (6) above, further comprising:

[0524] One or more internal microphones are disposed inside the housing, wherein

[0525] The signal processing unit

[0526] It further includes a third filter that generates the acoustic control signal based on sound collected by a third microphone contained in the one or more internal microphones.

[0527] (8) The acoustic output device according to (7) above, wherein,

[0528] The signal processing unit

[0529] It further includes a fourth filter that generates the acoustic control signal based on sound collected by a fourth microphone included in the one or more internal microphones.

[0530] (9) The acoustic output device according to (8) above, wherein,

[0531] The third microphone is configured to collect sound in a fifth direction inside the housing, and wherein,

[0532] The fourth microphone is configured to collect sound from a sixth direction, different from the fifth direction, inside the housing.

[0533] (10) The acoustic output device according to (9) above, wherein,

[0534] The signal processing unit

[0535] A third acoustic control signal for generating the acoustic control sound is generated for the first driver, and a fourth acoustic control signal for generating the acoustic control sound is generated for the second driver, based on the sound collected by the third microphone and the sound collected by the fourth microphone, respectively.

[0536] (11) The acoustic output device according to (10) above, wherein,

[0537] The signal processing unit

[0538] The enhanced sound is positioned based on the sound collected by each of the outward-facing microphones included in the housing on each of the left and right sides of the listener, and based on the positioned sound, the enhanced sound output signal is generated by each of the two or more drivers included in the housing on each of the left and right sides of the listener.

[0539] (12) The acoustic output device according to any one of (7) to (11) above, wherein,

[0540] The signal processing unit

[0541] With the listener wearing the shell, the listener's in-ear characteristics are measured based on the sound obtained by collecting sound generated by two or more drivers through one or more internal microphones.

[0542] (13) The acoustic output device according to (12) above, wherein,

[0543] The signal processing unit

[0544] Using at least one of the two or more drivers as a microphone, using the microphone in place of the one or more internal microphones, and measuring the listener's in-ear characteristics.

[0545] (14) The acoustic output device according to (12) above, wherein,

[0546] The signal processing unit

[0547] The state in which the listener wears the shell is determined based on the measured intraocular characteristics.

[0548] (15) The acoustic output device according to (13) above, wherein,

[0549] The signal processing unit

[0550] Using the driver, instead of the one or more internal microphones, the state of the listener wearing the housing is determined based on measured intraocular characteristics using the microphone.

[0551] (16) The acoustic output device according to (14) or (15) above further includes:

[0552] A communication unit, which communicates with a terminal device, wherein...

[0553] The signal processing unit transmits the determination result of the wearing status to the terminal device through the communication unit.

[0554] (17) The acoustic output device according to any one of (3) to (16) above, further comprising:

[0555] A communication unit, which communicates with a terminal device, wherein...

[0556] In the signal processing unit,

[0557] Configure functions to be executed based on instructions received from the terminal device by the communication unit.

[0558] (18) The acoustic output device according to any one of (3) to (17) above, wherein,

[0559] The signal processing unit

[0560] Each of the two or more drivers that reproduces an object sound source, and

[0561] An output signal is generated when each of the two or more drivers reproduces the object sound source based on the metadata added to the object sound source.

[0562] (19) The acoustic output device according to any one of (1) to (18) above, wherein,

[0563] The acoustically controlled sound includes:

[0564] Noise cancellation is used to eliminate sound leaking from the outside of the housing into the housing.

[0565] (20) The acoustic output device according to any one of (1) to (19) above, wherein,

[0566] The acoustically controlled sound includes:

[0567] Amplify sound, enhance the sound generated on the outside of the casing in a specific direction.

[0568] (21) A method for controlling an acoustic output device, the method comprising:

[0569] Processor, the processor enables

[0570] Each of two or more drivers is mounted on the housing, and one or more microphones are mounted on the housing facing outward to generate acoustic control sounds based on acoustic control signals.

[0571] Reference number list

[0572] 20, 20L, 20R, 20C rr ,201,202,20 Q noise

[0573] 20 BIG High sound pressure level noise

[0574] 21, 211, 212, 21 J , 22, 23, 231, 232, 23 L ,24,241,242,24 K 25, 251, 252, 25 L 25 11 25 21 25 L1 25 12 2522 25 L2 25 1K 25 2K 25 LK 180 11 180 21 180 Q1 180 12 180 22 180 Q2 180 1J 180 2J 180 QJ space

[0575] 40 heads

[0576] Headphones 50, 51, 52, 53, 54, 55, 56, 57

[0577] 60 Ear canal

[0578] 61. Eardrum

[0579] 80L, 80R, 80L rr 80R rr 81 Beamforming

[0580] 82, 83 reproduce sound

[0581] 100, 1001, 1002, 100 J 100L fwd 100L cent 100L rr 100R fwd 100R cent 100R rr FF microphone

[0582] 101, 1011, 1012, 101 K FB microphone

[0583] 110, 1101, 1102, 110 J ,111,1111,1112,111 K microphone amplifier

[0584] 120, 1201, 1202, 120 L 120 11 120 21 120 J1 120 12 120 22 120 J2 120 1L 120 2L120 JL 320a, 320b FFNC filters

[0585] 121, 121 11 ,1211,1212,121 L ,121 12 ,121 1L ,121 21 ,121 22 ,121 2L ,121 K1 ,121 K2 ,121 KL 320c FBNC filter

[0586] 130, 1301, 1302, 130 L 130a, 130b, 130c driver amplifiers

[0587] 140, 1401, 1402, 1403, 140 L 140 tw 140 mid 140 wf 140a, 140b, 140c, 140 Lfwd 140 Lcnt 140 Lrr 140R fwd 140R cnt 140R rr drive

[0588] 150 sound pressure levels

[0589] 160, 162, 163, 1631, 1632, 163 K Addition unit

[0590] 1611, 1612, 161 L , 1641, 1642, 164 L ,1651,1652,165 L ,1661,1662,166 L , 1671, 1672, 167 Q , 1681, 1682, 168 L Adders 313 and 314

[0591] 170, 1701, 1702, 1703, 170 11 170 12 170 13 170 21 170 22 17023 170 31 170 32 170 33 170 N1 170 N2 170 1L 170 2L 170 NL ,331,331 11 ,331 21 ,331 Q1 ,331 12 ,331 22 ,331 Q2 ,331 1L ,331 2L ,331 QL Positioning Filter

[0592] 1801, 1802, 180 L Gain Adjustment Unit

[0593] 200, 200a, 200b, 200c, 200d ADC

[0594] 201DAC

[0595] 210 Memory

[0596] 211 Operation Unit

[0597] 212 Communication Unit

[0598] 300a, 300b, 300c, 300d, 300e, 300f, 300g, 300h, 300i, 300j, 300k, 300lDSP

[0599] 310 control unit

[0600] 311, 334EQ

[0601] 312, 332, 3321, 3322, 332 L Horizontal control unit

[0602] 321 FF 321 FB Elimination control unit

[0603] 330, 330 11 330 21 330 J1 330 12 330 22 330 J2 330 1Q 3302Q 330 JQ Blind spot BF filter

[0604] 333 Mouth BF Filter

[0605] 335 Voice Source Setting Filter

[0606] 340 Measurement signal generation unit

[0607] 350 Measurement Data Acquisition Unit

[0608] 351 Correction Value Calculation Unit

[0609] 352FBNC filter correction unit

[0610] 353 Reproduction EQ Correction Unit

[0611] 354FF / FBNC filter correction unit

[0612] 360° filter unit

[0613] 361 Correction Processing Unit

[0614] 400, 401, 402, 403, 404, 405, 406, 407, 407', 408, 409, 410 wavefronts

[0615] 510 Earpads

[0616] 520, 520L, 520R housings

[0617] 530 headband

[0618] 6001, 6002, 6003, 600 N 710 Object Sound Source

[0619] 6012, 6012, 6013 reproduce sound

[0620] 700 audio signal

[0621] 720 Speaker's Voice Signal

[0622] 730 Input Signal

[0623] 900 terminal equipment

[0624] 901 Monitor

[0625] Areas 910, 930, and 931

[0626] 911 frame

[0627] 912 News

[0628] Buttons 920, 921, 931a, and 931b

[0629] 922 voice message

[0630] Areas 930 and 931

[0631] Checkboxes 930a, 930b, 930c, 930d, and 930e.

Claims

1. An acoustic output apparatus comprising: a housing; one or more outward microphones disposed on the housing facing an outside of the housing; and two or more drivers disposed inside the housing and each generating an acoustic control sound based on an acoustic control signal; and a signal processing unit generating the acoustic control signal, the two or more drivers include a first driver and a second driver, the first driver is configured at a different position from the second driver, the signal processing unit generates the acoustic control signal when each of the two or more drivers reproduces an object sound source based on meta information added to the object sound source. 2.The acoustic output apparatus of claim 1, wherein the first driver is disposed such that a sound wave to be emitted propagates in a first direction, and wherein the second driver is disposed such that a sound wave to be emitted propagates in a second direction different from the first direction. 3.The acoustic output apparatus of claim 1, wherein the signal processing unit includes a first filter generating the acoustic control signal based on a sound collected by a first microphone included in the one or more outward microphones. 4.The acoustic output apparatus of claim 3, wherein the signal processing unit further includes a second filter generating the acoustic control signal based on a sound collected by a second microphone included in the one or more outward microphones. 5.The acoustic output apparatus of claim 4, wherein the first microphone is disposed on the housing to collect a sound in a third direction, and wherein the second microphone is disposed to collect a sound in a fourth direction different from the third direction. 6.The acoustic output apparatus of claim 5, wherein the signal processing unit generates a first acoustic control signal for the first driver to generate the acoustic control sound and a second acoustic control signal for the second driver to generate the acoustic control sound based on respective sounds collected by the first microphone and the second microphone. 7.The acoustic output apparatus of claim 1, further comprising: one or more internal microphones disposed inside the housing, wherein the signal processing unit further includes a third filter generating the acoustic control signal based on a sound collected by a third microphone included in the one or more internal microphones. 8.The acoustic output apparatus of claim 7, wherein the signal processing unit further includes a fourth filter generating the acoustic control signal based on a sound collected by a fourth microphone included in the one or more internal microphones. 9.The acoustic output apparatus of claim 8, wherein the third microphone is disposed to collect a sound in a fifth direction inside the housing, and wherein the fourth microphone is disposed to collect a sound in a sixth direction inside the housing different from the fifth direction. 10.The acoustic output apparatus of claim 9, wherein ​ The signal processing unit generates a third acoustic control signal for the first driver to generate the acoustic control sound and a fourth acoustic control signal for the second driver to generate the acoustic control sound, based on sound collected by the third microphone and sound collected by the fourth microphone, respectively.

11. The acoustic output apparatus according to claim 10, wherein The signal processing unit sets a position of an enhanced sound based on sound collected by each of the outward microphones included in the housing worn on each of the left side and the right side of a listener, and generates an output signal of the enhanced sound in each of the two or more drivers included in the housing worn on each of the left side and the right side of the listener, based on the set position.

12. The acoustic output apparatus according to claim 7, wherein The signal processing unit measures an in-ear characteristic of a listener based on sound obtained by sound generated by the two or more drivers collected by the one or more internal microphones in a state in which the listener wears the housing.

13. The acoustic output apparatus according to claim 12, wherein The signal processing unit uses at least one of the two or more drivers as a microphone, uses the microphone instead of the one or more internal microphones, and measures the in-ear characteristic of the listener.

14. The acoustic output apparatus according to claim 12, wherein The signal processing unit determines a condition in which the listener wears the housing according to the measured in-ear characteristic.

15. The acoustic output apparatus according to claim 13, wherein The signal processing unit determines a condition in which the listener wears the housing according to the in-ear characteristic measured using the microphone using a driver instead of the one or more internal microphones.

16. The acoustic output apparatus according to claim 1, further comprising: a communication unit that communicates with a terminal device, wherein in the signal processing unit, a function to be executed according to an instruction received by the communication unit from the terminal device is set.

17. The acoustic output apparatus according to claim 1, wherein The acoustic control sound includes: a noise canceling sound for canceling sound leaked from an outside of the housing to an inside of the housing.

18. The acoustic output apparatus according to claim 1, wherein The acoustic control sound includes: an enhanced sound for enhancing sound generated in a specific direction outside the housing.

19. A method of controlling an acoustic output apparatus, the method comprising: generating, by a processor an acoustic control signal; causing each of two or more drivers provided inside a housing to generate an acoustic control sound based on the acoustic control signal, wherein one or more microphones are provided toward an outside on the housing, wherein the two or more drivers include a first driver and a second driver, the first driver is disposed at a different position from the second driver, the processor generating the acoustic control signals when each of the two or more drivers reproduces an object sound source based on meta-information added to the object sound source.

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