Audio output device and method for controlling an audio output device

Abstract

The acoustic output device according to the present disclosure comprises: a housing (520), at least one outwardly-directed microphone (100) provided in the housing so as to be directed toward the outside of the housing, and at least two drivers (140(1)-(L)) which are provided inside the housing and which respectively generate acoustic control sounds on the basis of acoustic control signals. In addition, in the control method for the acoustic output device according to the present disclosure, a processor (300a) causes the at least two drivers, provided inside the housing in which the at least one microphone is provided so as to be directed toward the outside thereof, to generate acoustic control sounds on the basis of acoustic control signals.

Description

Technical Field

[0001] The present disclosure relates to an acoustic output device and a method for controlling the acoustic output device.

Background Art

[0002] A noise canceling system is known in which a microphone for picking up external sounds is provided on a housing of an acoustic output device (hereinafter, appropriately referred to as a head-mounted acoustic output device) that is worn on the head or outer ear, such as headphones or earphones, and signal processing is performed based on the sound picked up by this microphone to remove the sound (external noise) that arrives from the outside to the auricle. In this noise canceling system, for example, a sound signal having a phase opposite to that of the sound picked up by the microphone is added to the sound signal originally output by the head-mounted acoustic output device to achieve external noise removal.

[0003] Patent Document 1 discloses headphones in which a speaker array having a plurality of speakers arranged inside the headphone housing is mounted inside the housing. By adopting such a configuration, it is possible to improve the sound image localization when listening to two-channel audio signals of L (left) and R (right) channels with the headphones.

[0004] Further, Patent Document 2 discloses headphones in which a plurality of microphones (referred to as FF microphones) for noise canceling by feedforward are mounted outside the headphone housing. In Patent Document 2, in such a configuration, while performing noise canceling, control is realized in which external sounds or noises from a specific direction are not canceled.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, considering the recent scenes of listening to music, etc., due to the spread of portable small music players and smartphones, many users can be seen listening to music outdoors using headphones. Considering such a situation, in Patent Document 1, outdoor use is not considered, and there is a risk that the sound image localization may become unclear due to ambient noise (noise) leaking into the headphone housing. Further, in Patent Document 2, although external sounds from a specific direction can be canceled, there is a risk that the sound image localization may become unclear due to external sounds leaking in from other than a specific direction.

[0007] An object of the present disclosure is to provide an acoustic output device capable of outputting a clearer reproduced sound and a control method for the acoustic output device.

Means for Solving the Problems

[0008] The acoustic output device according to the present disclosure includes a housing, one or more outward microphones provided on the housing and facing the outside of the housing, two or more drivers provided inside the housing and generating acoustic control sounds based on acoustic control signals respectively, and a signal processing unit for generating the acoustic control signals. One or more internal microphones provided inside the housing The acoustic output device includes two or more drivers including a first driver and a second driver, the first driver is arranged at a position different from the second driver, and the signal processing unit generates the acoustic control signals when reproducing the object sound source to each of the two or more drivers based on meta information added to the object sound source. Shi , Based on the sound picked up by the one or more internal microphones from the sound generated by the two or more drivers with the listener wearing the housing, measure the ear canal characteristics of the listener, use at least one of the two or more drivers as a microphone, and use this microphone instead of the one or more internal microphones for measuring the ear canal characteristics .

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same parts are denoted by the same reference numerals, and redundant explanations are omitted.

[0011] Hereinafter, embodiments of the present disclosure will be described in the following order. 1. Overview of Embodiments 2. First Embodiment 2-1. Regarding Existing Technologies 2-2. Configuration According to the First Embodiment 2-3. Effects of the First Embodiment 2-4. Variations of the First Embodiment 3. Second Embodiment 3-1. Configuration According to the Second Embodiment 3-2. Effects of the Second Embodiment 4. Third Embodiment 4-1. Regarding Existing Technologies 4-2. Configuration According to the Third Embodiment 5. Fourth Embodiment 6. Fifth Embodiment 6-1. Variations of the Fifth Embodiment 7. Sixth Embodiment 7-1. Variations of the Sixth Embodiment 8. Seventh Embodiment 8-1. First Variation of the Seventh Embodiment 8-2. Second Variation of the Seventh Embodiment 8-3. Third Variation of the Seventh Embodiment 9. Eighth Embodiment 10. Ninth Embodiment

[0012] [1. Overview of Embodiments] First, an overview of the embodiments of the present disclosure will be described. The present disclosure relates to an acoustic output device worn on the head by a user. The acoustic output device applicable to the present disclosure includes over-ear (or on-ear) type headphones (hereinafter referred to as headphones) that supply the sound generated by the diaphragm vibrating in response to an audio signal in a driver unit from the vicinity of the listener's auricle.

[0013] Conventionally, a microphone is provided on the outside of the headphone housing facing outward from the housing, and based on the sound collected by this microphone, a signal for canceling noise leaking into the headphones from the outside is generated. A headphone having a feedforward method (hereinafter, FF method) noise canceling function is known. Hereinafter, the headphone having this FF method noise canceling function will be appropriately referred to as an FF method noise canceling headphone.

[0014] Also, a headphone having a feedback method (hereinafter, FB method) noise canceling function that provides a microphone facing inward of the housing and cancels the leaking noise into the housing based on the sound collected by this microphone, and a headphone having a dual method noise canceling function that combines the FF method and the FB method are also known.

[0015] Hereinafter, the headphone having a noise canceling function will be appropriately referred to as a noise canceling headphone. Also, hereinafter, the headphone having an FF method noise canceling function will be appropriately referred to as an FF method noise canceling headphone, the headphone having an FB method noise canceling function will be referred to as an FB method noise canceling headphone, and the headphone having a dual method noise canceling function will be referred to as a dual method noise canceling headphone. Also, hereinafter, the microphone used to realize the FF method noise canceling function will be appropriately referred to as an FF microphone, and the microphone used to realize the FB method noise canceling function will be referred to as an FB microphone.

[0016] In these FF method noise canceling headphones, FB method noise canceling headphones, and dual method noise canceling headphones according to the prior art, in each case, only one driver unit (speaker) for generating a noise canceling sound based on the noise canceling signal is provided inside one housing.

[0017] The noise - canceling headphones as an acoustic output device according to the present disclosure have a configuration in which a plurality of driver units that generate sound according to an audio signal are provided in each housing that covers each of the user's left and right ears. Hereinafter, providing a plurality of driver units in each of the left and right housings in this way is referred to as multi - driver.

[0018] In the multi - driver type noise - canceling headphones as an acoustic output device according to the present disclosure, noise - canceling sound based on the sound picked up by the microphones provided in each housing is generated from the plurality of driver units provided in the housing. In this way, in an acoustic output device in which a plurality of driver units are provided in each of the left and right housings, by generating noise - canceling sound from each of these plurality of driver units, it becomes possible to obtain a higher noise - canceling effect.

[0019] Note that the acoustic output device of the present disclosure is basically configured to generate a noise - canceling signal for noise - canceling by observing (picking up) ambient noise with an FF microphone provided outwardly on the housing of the headphones. Therefore, considering that one or more FF microphones are mounted on each of the left and right housings, the following patterns are conceivable.

[0020] (1) The first pattern is a multi - driver type noise - canceling headphone in which one FF microphone is mounted on each housing. This configuration is hereinafter appropriately referred to as a single - mic multi - driver type FF - method noise - canceling headphone. (2) The second pattern is a multi - driver type noise - canceling headphone in which two or more FF microphones are mounted on each housing. This configuration is hereinafter appropriately referred to as a multi - mic multi - driver type FF - method noise - canceling headphone.

[0021] [2. First Embodiment] The first embodiment according to the present disclosure will be described.

[0022] (2-1. Regarding the existing technology) First, for easier understanding, the single-microphone, single-driver FF method noise cancellation by the existing technology will be described. FIG. 1 is a diagram showing the configuration of a single-microphone single-driver type FF method noise cancellation headphone by the existing technology using a transfer function.

[0023] In FIG. 1, the FF microphone (FF microphone) 100 is an outward-facing microphone provided toward the outside of the headphone housing (not shown). For example, the FF microphone 100 is omnidirectional, provided outside the headphone housing, and picks up the sound outside the housing. The noise 20 of characteristic “N” generated outside the housing is picked up by the FF microphone 100 through the space 21 of the spatial transfer function X. The sound signal output from the FF microphone 100 is supplied to the microphone amplifier 110 and amplified. The transfer function including the FF microphone 100 and the microphone amplifier 110 is “M”. The output of the microphone amplifier 110 is passed to the FFNC (FF Noise Canceling) filter 120 with a filter coefficient α for performing FF method noise cancellation (NC).

[0024] The FFNC filter 120 generates a noise cancellation signal for generating a noise cancellation sound that cancels noise based on the input signal. The noise cancellation signal generated by the FFNC filter 120 is passed to the driver amplifier 130 with a transfer function A. The driver amplifier 130 drives the driver unit 140 (described as driver 140 in the figure) with a transfer function D in response to the passed noise cancellation signal. The driver 140 generates a noise cancellation sound by air vibration in response to the noise cancellation signal. The noise cancellation sound is transmitted from the driver 140 toward the control point (for example, the eardrum of the user wearing the headphone) through the space 23 of the spatial transfer function G.

[0025] Here, the noise canceling sound is an acoustic control sound for controlling the acoustics within the housing of the headphones (space 23), and it can be considered that the noise canceling signal is an acoustic control signal for the driver 140 to reproduce the acoustic control sound.

[0026] Note that hereinafter, unless otherwise specified, the driver unit 140 will be described as the driver 140.

[0027] On the other hand, the noise 20 travels through the space 22 of the spatial transfer function F and leaks into the headphones through the housing of the headphones. The noise 20 that has leaked into the headphones is added to the noise canceling sound generated by the driver 140 with the space within the housing as the adder 160, and the noise 20 is canceled. The sound obtained by canceling the noise 20 with the noise canceling sound reaches the eardrum of the user as the sound pressure 150 of the sound pressure (p).

[0028] At this time, since the FFNC filter 120 only requires the sound pressure (p) at the eardrum position to be "0", the filter coefficient α can be obtained by the following equation (1).

[0029]

Equation

[0030] When solving equation (1) for the filter coefficient α, the following equation (2) is obtained.

[0031]

Equation

[0032] By determining the filter coefficient α of the FFNC filter 120 in this way, the user wearing the headphones can listen to the sound obtained by canceling the noise 20 generated outside the housing of the headphones.

[0033] (2-2. Configuration according to the first embodiment) Next, a configuration according to a first embodiment of the present disclosure will be described. The first embodiment relates to the single-microphone multi-driver type FF method noise canceling headphones described above.

[0034] FIG. 2 is a schematic diagram schematically showing a vertical cross-section of an appearance of an example of single-microphone multi-driver type FF method noise canceling headphones 50 applicable to the first embodiment. Hereinafter, the "single-microphone multi-driver type FF method noise canceling headphones 50" will be simply described as "headphones 50". Note that FIG. 2 shows the right housing among the left and right housings of the headphones 50.

[0035] In FIG. 2, the headphones 50 are connected to the housing 520 on the opposite side (the right side in this example) of the housing 520 by a headband (not shown). Further, ear pads 510 are provided at the edge of the housing 520, and the ear pads 510 of the left and right housings 520 are pressed against the head 40 of the user wearing the headphones 50.

[0036] Inside the housing 520, L drivers 1401, 1402,..., 140 L are provided. In the example of FIG. 2, with L = 3, three drivers 1401, 1402, and 140 L are provided with respect to the housing 520. The L drivers 1401, 1402,..., 140 L are arranged in the housing 520 such that, for example, the sound waves radiated therefrom travel in different directions from each other.

[0037] Note that in the example of FIG. 2, these drivers 1401, 1402, and 140 L are shown to be aligned in a substantially vertical direction when the user wears the headphones 50 in a normal state, but this is not limited to this example. For example, the drivers 1401, 1402, and 140 L may be arranged to be aligned in a horizontal direction or an oblique direction, or may be arranged at the respective vertices of a triangle.

[0038] In the example of FIG. 2, among these, the driver 1401 is arranged at a position and in a direction where the emitted sound (air vibration) can be directly transmitted to the user's eardrum 61 through the ear canal 60. In other words, the driver 1401 is arranged at a substantially central portion inside the housing 520 so as to be able to output sound in the direction of the eardrum 61.

[0039] Also, the drivers 1402 and 140 L are respectively arranged at positions from the central portion to the edge portion of the housing 520. More specifically, the driver 1402 is arranged obliquely in the upper part of the housing 520 toward the ear canal 60. Also, the driver 140 L is arranged in the lower part of the housing 520 facing upward.

[0040] Furthermore, the FF microphone 100 is arranged outside the housing 520 of the headphones 50. In the example of FIG. 2, the FF microphone 100 is arranged at a position facing the driver 1401 through the housing 520 with the sound collection part facing outside the housing 520.

[0041] Note that in FIG. 2, the driver 1401 is arranged with respect to the housing 520 such that the emitted sound (sound wave) travels by a wavefront substantially perpendicular to the direction of the eardrum 61, but the arrangement of the driver 1401 with respect to the housing 520 is not limited to this example. For example, the driver 1401 may be arranged on the housing 520 such that the wavefront of the emitted sound travels by an oblique wavefront with respect to the direction of the eardrum 61 schematically shown by the ear canal 60 and the eardrum 61 in the figure. Also, for example, in FIG. 2, the driver 1401 is arranged on the axis by the eardrum 61 and the ear canal 60 schematically shown, but the driver 1401 may be arranged at a position shifted from the axis on the housing 520. Furthermore, it is also conceivable to arrange the driver 1401 at the peripheral edge of the housing 520. The position of the FF microphone 100 is not limited to a position facing the driver 1401 through the housing 520.

[0042] FIG. 3A is a schematic diagram schematically showing the configuration of an example of an acoustic output device according to the first embodiment. In the example of FIG. 3A, the acoustic output device includes a headphone 50, a microphone amplifier 110, driver amplifiers 1301, 1302, …, 130 L and an ADC 200, a DAC 201, a memory 210, an operation unit 211, and a DSP 300a. The operation unit 211 is provided with operators for receiving user operations. The DSP 300a executes control according to a program in response to a user operation on the operation unit 211.

[0043] In FIG. 3A, since the configuration of the headphone 50 is the same as that in FIG. 2, the description here is omitted. In this example where the headphone 50 includes three drivers 1401, 1402, and 140 L in this example where the headphone 50 includes three drivers 1401, 1402, and 140 L it has three driver amplifiers 1301, 1302, and 130 corresponding to these drivers 1401, 1402, and 140 L respectively.

[0044] The ADC (Analog to Digital Converter) 200 converts an analog audio signal based on the sound picked up by the FF microphone into a digital audio signal. The DSP (Digital Signal Processor) 300a receives as input the audio signal converted into a digital signal by the ADC 200 and the audio signal 700 mainly listened to by this headphone 50.

[0045] Note that in FIG. 3A and the subsequent figures, the symbol “ / (slash)” or the symbol “\(backslash)” attached to a signal line indicates that the signal line includes a plurality of signal lines or transmits signals of a plurality of channels.

[0046] FIG. 3B is an example of a functional block diagram for explaining the function of the DSP 300a according to the first embodiment. In FIG. 3B, the DSP 300a includes a control unit 310, an EQ (equalizer) 311, a level control unit 312, an adder 313, an FFNC filter 320a, and a cancellation amount control unit 321FF including

[0047] These control unit 310, EQ 311, level control unit 312, adder 313, FFNC filter 320a and cancellation amount control unit 321 FF are realized by executing an acoustic output control program on the DSP 300a. Not limited to this, the control unit 310, EQ 311, level control unit 312, adder 313, FFNC filter 320a and cancellation amount control unit 321 FF may be configured, in part or in whole, using hardware circuits that cooperate with each other.

[0048] For example, when the acoustic output control program is executed, the DSP 300a configures the control unit 310, EQ 311, level control unit 312, adder 313, FFNC filter 320a and cancellation amount control unit 321 FF as, for example, modules in a memory area (not shown) that is the main memory area of the DSP 300a. Note that the acoustic output control program is stored in advance in, for example, the memory 210, and is made executable when the DSP 300a reads it from the memory 210 at startup. Also, the acoustic output control program may be provided from the outside via communication means (not shown) and stored in the memory 210 or the like.

[0049] In the DSP 300a, the control unit 310 controls each part of the DSP 300a according to, for example, a program stored in the memory 210. Also, the control unit 310 controls each part of the DSP 300a according to a program in response to an operation on the operation unit 211.

[0050] The externally input audio signal 700 is supplied to the EQ 311 for EQ processing, and the level (volume) is adjusted in the level control unit 312. The audio signal 700 whose level is adjusted by the level control unit 312 is passed to the adder 313. Note that various parameters in the EQ 311 and the level control unit 312 can be changed by the control of the control unit 310 according to, for example, a user operation on the operation unit 211.

[0051] The sound signal supplied from the ADC 200 is input to the FFNC filter 320a with a filter coefficient α. The FFNC filter 320a includes the functions of L drivers 1401, 1402,..., 140 L Corresponding to each, it includes the functions of L FFNC drivers, and based on the input sound signal, noise cancellation signals for the drivers 1401, 1402,..., 140 L are generated respectively by the following processing. Each noise cancellation signal generated by the FFNC filter 320a is sent to the cancellation amount control unit 321 FF where the level is adjusted respectively and passed to the adder 313.

[0052] Note that the parameters in the FFNC filter 320a and the cancellation amount control unit 321 FF can be changed by the control of the control unit 310 according to, for example, a user operation on the operation unit 211. For example, the control unit 310 can switch the FFNC filter 320a to an FFNC filter with different characteristics according to a user operation. As an example, the control unit 310 can switch the default FFNC filter 320a to an FFNC filter with optimized parameters for a specific noise (such as airplane noise) according to a user operation. Also, the control unit 310 can adjust the cancellation amount of the noise 20 by the noise cancellation signal by controlling the parameters of the cancellation amount control unit 321 FF

[0053] The adder 313 adds the audio signal 700 passed from the level control unit 312 and the cancellation amount control unit 321 FF ​Each driver 1401, 1402, …, 140 passed from L is combined with each corresponding noise cancellation signal and output. Each signal output from the DSP 300a in this way becomes an acoustic signal obtained by adding together the audio signal 700 and a signal for canceling the noise components generated outside the housing 520.

[0054] In this way, the DSP 300a functions as a signal processing unit that generates a noise cancellation signal as an acoustic control signal.

[0055] Returning to FIG. 3A for the description, each acoustic signal output from the DSP 300a is passed to a DAC (Digital to Analog Converter) 201, and the digital acoustic signal is converted into an analog acoustic signal. Each acoustic signal converted into an analog format by the DAC 201 is supplied to driver amplifiers 1301, 1302, and 130 L respectively. Each of the driver amplifiers 1301, 1302, and 130 L drives the drivers 1401, 1402, and 140 L respectively based on the supplied acoustic signal.

[0056] As a result, the user wearing this headphone 50 can listen to the sound based on the audio signal 700 with the noise 20 generated outside the housing 520 of the headphone 50 suppressed.

[0057] FIG. 4 is a diagram showing the configuration of the acoustic output device according to the first embodiment using a transfer function. Note that in FIG. 4, only one of the configurations on the left and right sides of the headphone 50 is shown. The configuration shown in FIG. 4 is a configuration in which the configurations of the FFNC filter 120, the driver amplifier 130, the driver 140, and the space 23 in the configuration according to the existing technology shown in FIG. 1 are connected in parallel by the number of drivers 1401, 1402, …, 140 L etc.

[0058] In FIG. 4, the FFNC filters 1201, 1202, …, 120 Lis realized by the FFNC filter 320a in FIG. 3B, with filter coefficients α1, α2, …, α L , respectively. Also, the driver amplifier 1301 and driver 1401, driver amplifier 1302 and driver 1402, …, driver amplifier 130 L and driver 140 L have transfer functions of transfer function A1 and D1, transfer function A2 and D2, …, transfer function A L and D L , respectively. Further, the spaces 231, 232, …, 23 L have spatial transfer functions G1, G2, …, G L , respectively.

[0059] That is, in FIG. 4, the configuration in which the FFNC filter 1201, driver amplifier 1301, driver 1401, and space 231 are connected is a configuration for generating a canceling sound generated by the driver 1401. Similarly, the configuration in which the FFNC filter 1202, driver amplifier 1302, driver 1402, and space 232 are connected is a configuration for generating a canceling sound generated by the driver 1402. Also, the configuration in which the FFNC filter 120 L , driver amplifier 130 L , driver 140 L and space 23 L are connected is a configuration for generating a canceling sound generated by the driver 140 L .

[0060] The sound signal based on the sound picked up by the FF microphone is passed from the microphone amplifier 110 to the FFNC filters 1201, 1202, …, 120 L , respectively. The sound signal is passed to the driver 1401 via, for example, the FFNC filter 1201 and the driver amplifier 1301 to generate a noise canceling sound, and the generated noise canceling sound is input to the adder 160 through the space 231 inside the housing 520.

[0061] The FFNC filters 1202, …, 120L Similarly, the passed audio signals are respectively passed to drivers 1402, …, 140 L via driver amplifiers 1302, …, 130 L and are respectively regarded as noise canceller sounds, and are input to the adder 160 via spaces 232, …, 23 L . The adder 160 adds and outputs, within the space of the housing 520, each noise canceller sound input via spaces 231, 232, …, 23 L and the noise 20 outside the housing 520 input to the adder 160 via the space 22. The output of the adder 160 reaches the eardrum 61 of the user wearing the headphones 50 as sound pressure 150 (sound pressure (p)).

[0062] As shown in FIG. 4, since it is sufficient to be able to cancel the leakage noise (NF) at the position of the eardrum 61, setting the sound pressure (p) = 0 at the eardrum 61, the following equation (3) obtained by expanding the above-described equation (1) to parallel processing can be obtained.

[0063]

Equation

[0064] By transforming equation (3), the following equation (4) is obtained.

[0065]

Equation

[0066] As the filter coefficients α of each FFNC filter 1201, 1202, …, 120 L , filter coefficients α1, α2, …, α L that satisfy this equation (4) are obtained, noise cancellation is possible when using one FF microphone and L drivers 1401, 1402, …, 140 L .

[0067] (2-3. Effects according to the first embodiment) Next, the effects according to the first embodiment will be described. In the first embodiment, by mounting a plurality of drivers 1401, 1402, …, 140 on the housing 520 of the headphones 50, the noise cancellation performance can be improved with respect to the single microphone - single driver type FF noise - canceling headphones according to the existing technology described with reference to FIG. 1. L Among them, any one of the plurality of drivers 1401, 1402, …, 140 is referred to as driver 140. Also, among the plurality of FFNC filters 1201, 1202, …, 120, the FFNC filter corresponding to driver 140 is the FFNC filter 120 with filter coefficient α.

[0068] Hereinafter, among the plurality of drivers 1401, 1402, …, 140 L any driver is taken as driver 140 x And among the plurality of FFNC filters 1201, 1202, …, 120 L the FFNC filter corresponding to driver 140 x is the FFNC filter 120 with filter coefficient α x x

[0069] Regarding the configuration in the first embodiment in which a plurality of drivers 1401, 1402, …, 140 are provided on the housing 520, the following three reasons can be cited as to why the noise cancellation performance can be improved compared to the configuration using a single driver 140 according to the existing technology. L

[0070] (1) The degree of freedom of the filter coefficient α of the FFNC filter 120 x is higher than that of the filter coefficient of the FFNC filter 120 of the existing technology. As a result, the noise cancellation signal can be accurately generated and reproduced. x (2) Among the plurality of drivers 1401, 1402, …, 140 L the noise cancellation signal can be reproduced from the driver 140 x at a position close to the arrival direction of the noise 20. (3) Even in the situation of high - sound - pressure noise, the noise cancellation signal can be accurately reproduced.

[0071] (Response to the arrival direction of noise) ​​​​Reasons (1) and (2) will be described with reference to FIGS. 5 and 6. FIGS. 5 and 6 are schematic diagrams for explaining the effects of the acoustic output device according to the first embodiment, respectively.

[0072] FIG. 5 shows the case where the noise 20 arrives from a direction horizontal to the housing 520, that is, a direction parallel to the direction in which the FF microphone and the driver 1401 face.

[0073] Section (a) of FIG. 5 schematically shows the wavefront 400 of the noise 20 reaching the FF microphone provided in the housing 520, the earpad 510 provided in the housing 520, and the wavefront 401 of the noise 20 leaking through the gap between the head 40 of the user wearing the headphones 50. The noise 20 reaches the FF microphone through the space of the spatial transfer function X, and as shown by the paths A and A', it leaks into the inside of the housing 520 through the space of the spatial transfer function F from the gap between the earpad 510 and the head 40 and reaches the eardrum 61 through the ear canal 60.

[0074] Section (b) of FIG. 5 schematically shows an example of the wavefront of each noise canceling sound reproduced by the noise canceling signal generated based on the noise 20 picked up by the FF microphone and output from each of the drivers 1401, 1402, and 140 L The noise canceling sounds indicated by the wavefronts 402, 403, and 404 respectively output from the drivers 1401, 1402, and 140 L are synthesized at the entrance of the ear canal 60 and reach the eardrum 61 as the sound indicated by the wavefront 405. The sound indicated by this wavefront 405 is ideally a sound having a phase opposite to that of the wavefront 401 due to the leakage noise shown in section (a), for example.

[0075] Section (c) of FIG. 5 schematically shows the state of adding section (a) and section (b) of FIG. 5. Specifically, in section (c) of FIG. 5, each of the drivers 1401, 1402, and 140 LThe sound indicated by the wavefront 405, which is reproduced by [reference] and synthesized at the entrance of the external auditory canal 60, and the sound indicated by the wavefront 401 of the noise 20 that leaks in from the gap between the earpad 510 and the head 40 are synthesized and reach the eardrum 61, which is schematically shown.

[0076] Since the wavefront 401 of the leakage noise and the wavefront 405 of the noise canceling sound substantially coincide, the leakage noise is canceled by the noise canceling sound. Therefore, the user wearing this headset 50 can listen to the sound in which the leakage noise is suppressed by the noise canceling sound.

[0077] FIG. 6 shows the case where the noise 20 arrives from a direction perpendicular to the housing 520, that is, a direction perpendicular to the direction in which the FF microphone and the driver 1401 face (in the example of FIG. 6, upward).

[0078] Section (a) of FIG. 6 schematically shows the wavefront 406 of the noise 20 reaching the FF microphone provided in the housing 520, the earpad 510 provided in the housing 520, and the wavefront 407 of the noise 20 leaking in from the gap between the head 40 of the user wearing the headset 50. The noise 20 reaches the FF microphone via the path B in the space of the spatial transfer function X, and leaks into the inside of the housing 520 from the upper gap between the earpad 510 of the housing 520 and the head 40 via the path C in the space of the spatial transfer function F.

[0079] Section (b) of FIG. 6 shows an example of the wavefront by each noise canceling sound reproduced by each driver 1401, 1402, and 140 L output from the noise canceling signal generated based on the noise 20 picked up by the FF microphone. L by each driver 1401, 1402, and 140

[0080] In this example, noise 20 arrives from above the headphones 50, and the noise cancellation signal is actively reproduced from the driver 1402 disposed at the upper part of the housing 520, which is closer to the arrival position of the noise 20, among the three drivers 1401, 1402 and 140 L In the driver amplifier 1302 corresponding to the driver 1402 disposed at the upper part of the housing 520, which is closer to the arrival position of the noise 20 among the drivers 1401, 1402 and 140

[0081] As a more specific example, as shown in section (b) of FIG. 6, in the driver amplifier 1302 corresponding to the driver 1402 disposed at the upper part of the housing 520 among the drivers 1401, 1402 and 140 L the highest level of noise cancellation signal is generated. The driver 1402 reproduces a noise canceling sound in response to this high level noise cancellation signal. This noise canceling sound travels, for example, toward the entrance of the external auditory canal 60 as shown by the wavefront 409.

[0082] For the driver 1401 disposed at the central part of the housing 520, in the driver amplifier 1301 corresponding to the driver 1401, a noise cancellation signal with a lower level (medium level) is generated as compared with the noise cancellation signal generated by the above-described driver amplifier 1302. The driver 1401 reproduces a noise canceling sound in response to this medium level noise cancellation signal. This noise canceling sound travels, for example, toward the entrance of the external auditory canal 60 as shown by the wavefront 410.

[0083] Furthermore, for the driver 140 disposed at the lower part of the housing 520 L in the driver amplifier 130 L corresponding to the driver 140 L a noise cancellation signal with an even lower level (low level) is generated as compared with the noise cancellation signal generated by the above-described driver amplifier 1301. The driver 140 L reproduces a noise canceling sound in response to this low level noise cancellation signal. In the example of the figure, the driver 140 L is made not to reproduce a noise canceling sound.

[0084] Each of the drivers 1401, 1402, and 140 L The noise canceling sounds reproduced by each are synthesized inside the housing 520, and the synthesized noise canceling sound is generated from the upper part to the lower part inside the housing 520 as shown by the wavefront 408 in the figure. The sound indicated by the wavefront 408 due to this synthesized noise canceling sound is, ideally, a sound having a phase opposite to that of the wavefront 407 due to the leakage noise shown in section (a), for example.

[0085] Section (c) of FIG. 6 schematically shows the state of adding together section (a) and section (b) of FIG. 6. Specifically, in section (b), the noise canceling sounds reproduced by each of the drivers 1401, 1402, and 140 L are synthesized, the sound shown by the wavefront 408, and the leakage noise shown by the wavefront 407 due to the noise 20 leaking in from the gap between the upper side of the earpad 510 and the head 40 in the housing 520 are synthesized. This synthesized sound reaches the eardrum 61.

[0086] Since the wavefront 407 of the leakage noise and the wavefront 408 of the sound synthesized with each noise canceling sound substantially coincide, the leakage noise is canceled by the noise canceling sound (wavefront 407'). The sound indicated by this wavefront 407' is the sound in which the leakage noise is canceled by each noise canceling sound, and the user wearing this headphone 50 can listen to the sound with the leakage noise from above suppressed.

[0087] As described above, according to the configuration of the first embodiment, in addition to the driver 1401 disposed at the center inside the housing 520 of the headphones 50, for example, a driver 1402 is mounted above the housing 520. Therefore, even when the noise 20 arrives from above the headphones 50, the noise cancellation corresponding to the arrival direction of the noise 20 can be achieved by actively reproducing the noise cancellation signal at the driver 1402 disposed at a position close to the arrival direction of the noise 20. As a result, the reproduced sound reproduced by the headphones 50 can be made clearer.

[0088] Note that the direction in which the noise 20 arrives at the headphones 50 can be estimated based on the sounds picked up by, for example, FF microphones provided respectively on the left and right housings 520 of the headphones 50 and a microphone directed upward of the headphones 50. Not limited to this, for example, according to the control of the control unit 310 in response to an operation on the operation unit 211, the settings of the respective FFNC filters 1201, 1202,..., 120 L and the respective driver amplifiers 1301, 1302,..., 130 L can also be switched to settings corresponding to the noise 20 from above.

[0089] FIG. 7 is a diagram schematically showing noise cancellation by a single-microphone single-driver type noise canceling headphone according to the prior art. In the headphones 51 shown in section (a) and section (b) of FIG. 7, only one driver 140 is provided at the center inside the housing 520. Also, an FF microphone is provided at a position facing the driver 140 with the housing 520 interposed therebetween. The configuration of this headphone 51 applies the configuration described using the transfer function in FIG. 1.

[0090] Section (a) of FIG. 7 shows the case where the noise 20 arrives from the horizontal direction with respect to the housing 520. Similar to section (a) of FIG. 5, the noise 20 leaks into the gap between the earpad 510 of the housing 520 and the head 40 as shown by paths A and A', and reaches the eardrum 61 through the external auditory canal 60 as the leaked noise. In this configuration, the noise 20 indicated by the wavefront 400 is picked up by the FF microphone, and the noise cancellation signal generated based on the picked-up noise 20 is reproduced as the noise cancellation sound by the driver 140. This noise cancellation sound is synthesized with the leaked noise in the space inside the housing 520 and reaches the eardrum 61 through the external auditory canal 60. Therefore, in the same manner as the explanation using sections (a) to (c) of FIG. 5, the user can listen to the sound in which the leaked noise is suppressed by the noise cancellation sound.

[0091] Section (b) of FIG. 7 shows the case where the noise 20 arrives from the vertical direction with respect to the housing, which was described with reference to FIG. 6. In this case, the headset 51 does not have a driver provided in the upper part of the housing 520. Therefore, it is difficult to cancel, as a wavefront, the leaked noise arriving from the upper side of the housing 520, indicated by the wavefront 407, by the cancellation sound arriving from the horizontal direction toward the external auditory canal 60 as shown by the wavefront 402.

[0092] As described above, in the case of the single microphone - single driver type, good noise cancellation is possible for the noise 20 arriving from the direction where the driver 140 is located, but there is a possibility that sufficient noise cancellation performance cannot be obtained for the noise 20 arriving from other directions.

[0093] (Response to high - sound - pressure noise) Next, the response to high - sound - pressure noise by providing a plurality of drivers 1401, 1402, …, 140 L will be described for the reason (3) mentioned above.

[0094] As described above, by arranging a plurality of drivers 1401, 1402, …, 140 in the housing 520, L compared with the case where only one FFNC filter 120 is arranged, the degree of freedom of the FFNC filter 120 x is increased. Since the degree of freedom of the FFNC filter 120 x is increased, noise cancellation signals for canceling the noise 20 can be reproduced from a plurality of drivers 1401, 1402, …, 140, L and accordingly, for example, noise cancellation can be performed even for very high sound pressure, large sound pressure noise.

[0095] FIG. 8 is a schematic diagram for explaining noise cancellation for large sound pressure noise according to the first embodiment. Section (a) of FIG. 8 is a schematic diagram for explaining cancellation of large sound pressure noise by a single microphone - single driver type FF - method noise - canceling headphone according to the prior art. In the figure, the headphone 51 is the same as the headphone 51 described with reference to FIG. 7. Only one driver 140 is provided at the central part in the housing 520, and an FF microphone is provided at a position facing the driver 140 via the housing 520.

[0096] The large sound pressure noise 20 BIG is picked up by the FF microphone as shown by the path D. The FFNC filter 120 with the filter coefficient α generates a noise cancellation signal for canceling the large sound pressure noise 20 picked up by the FF microphone, BIG and supplies the generated noise cancellation signal to the driver 140 via a driver amplifier 130 (not shown). The driver 140 reproduces a noise cancellation sound based on the noise cancellation signal generated in response to the large sound pressure noise 20. BIG BIG

[0097] On the other hand, the large sound pressure noise 20 BIGLeaks into the housing 520 from the gap between the earpad 510 and the head 40 along the path E and becomes leakage noise. Here, assume that the maximum sound pressure level that the driver 140 can drive is 80 [dBSPL (dB Sound Pressure Level)], and the sound pressure of the leakage noise at the position of the eardrum 61 is 100 [dBSPL]. In the existing technology, since only one driver 140 is provided in the housing 520, noise cancellation of up to 80 [dBSPL] can be achieved at most, and at the eardrum 61, which is the cancellation point, 20 [dBSPL] of leakage noise cannot be cancelled.

[0098] Section (b) of FIG. 8 shows a housing 520 according to the first embodiment, with a plurality (three in this example) of drivers 1401, 1402, and 140 L When provided, it is a schematic diagram for explaining the noise cancellation of high sound pressure noise 20 BIG .

[0099] High sound pressure noise 20 BIG As shown in path D, is picked up by the FF microphone, and is passed through the FFNC filters 1201, 1202,..., 120 with filter coefficients α1, α2,..., α L respectively. Each FFNC filter 1201, 1202,..., 120 L respectively generates a noise cancellation signal for canceling the high sound pressure noise 20 based on the high sound pressure noise 20 passed from the FF microphone. Each noise cancellation signal generated by each FFNC filter 1201, 1202,..., 120 L is respectively supplied to each driver 1401, 1402,..., 140 through driver amplifiers 1301, 1302,..., 130 (not shown) BIG . Each driver 1401, 1402,..., 140 BIG plays back a noise cancellation sound based on the noise cancellation signal generated respectively in response to the high sound pressure noise 20. L L L L BIG L BIG High sound pressure noise 20 BIG .

[0100] In this case, the sound pressure level of 100 [dBSPL] to be canceled by the cancel signal is dispersed and reproduced by a plurality of drivers 1401, 1402, and 140 L and reproduced.

[0101] In the example of section (b) of FIG. 8, the driver 1401 reproduces a canceling sound of 50 [dBSPL], the driver 1402 reproduces a canceling sound of 30 [dBSPL], and the driver 140 L reproduces a canceling sound of 20 [dBSPL], and the total sound pressure of the canceling sound reproduced by the three drivers 1401, 1402, and 140 L is set to 100 [dBSPL].

[0102] For example, the control unit 310 can make it possible to reproduce a noise canceling sound with a desired sound pressure in each of the drivers 1401, 1402, and 140 L by setting the filter coefficients α1, α2, and α of the FFNC filters 1201, 1202, and 120 L respectively to predetermined settings. Not limited to this, the control unit 310 can also control each of the driver amplifiers 1301, 1302, and 130 L respectively to reproduce a noise canceling sound with a desired sound pressure in each of the drivers 1401, 1402, and 140 L L L L

[0103] Thus, in the first embodiment, it is also possible to easily cope with noise canceling for large sound pressure noise 20 BIG As an example, by applying the noise canceling according to the first embodiment, it can be expected to protect the hearing of, for example, a DJ (Disc Jockey) performer who performs under a large sound pressure such as club music, or a worker who works under a large noise.

[0104] (2-4. Modification of the First Embodiment) Next, a modification of the first embodiment will be described. In the modification of the first embodiment, a plurality of drivers 1401, 1402, …, 140 L each is an example in the case of using them not as full-range drivers but as drivers that reproduce sound signals in each frequency band obtained by dividing the reproduction frequency band.

[0105] FIG. 9 is a schematic diagram schematically showing a vertical cross-section of the appearance of an example of headphones applicable to the modification of the first embodiment. In FIG. 9, headphones 52 include one FF microphone and three drivers 140 tw 、140 wf and 140 mid . Driver 140 tw is a tweeter that performs high-frequency reproduction, driver 140 mid is a midrange driver that performs midrange reproduction, and driver 140 wf is a woofer that performs low-frequency reproduction.

[0106] For example, in the configuration shown in FIG. 3A, the sound signal output from DAC 201 is filtered into high-frequency, mid-frequency, and low-frequency sound signals by a predetermined speaker network, and is supplied to drivers 140 tw 、140 mid and 140 wf respectively. FIG. 10 is a diagram schematically showing an example of the frequency characteristics of the sound signals supplied to each driver 140 tw 、140 mid and 140 wf . The sound signal tw supplied to driver 140 tw is a signal with a frequency band lower than the first frequency cut off, and the sound signal wf supplied to driver 140 wf is a signal with a frequency band higher than the second frequency and lower than the first frequency cut off. Also, the sound signal mid supplied to driver 140mid is a signal with a frequency band higher than the first frequency and a frequency band lower than the second frequency cut off.

[0107] Thus, a plurality of drivers 140 tw 、140mid and 140 wf By restricting the frequency band of the sound signals supplied to each, compared to the case of using a full-range driver, unnecessary peaks / notches do not appear in the frequency characteristics, so that the cancellation signal can be stably reproduced.

[0108] Next, regarding the point that the cancellation signal can be stably reproduced by band-splitting using a plurality of drivers 140 tw , 140 mid and 140 wf will be described while comparing with the prior art. The configuration of the FF method noise cancellation by the single-microphone single-driver type according to the prior art is as described using the transfer function in FIG. 1, and the filter coefficient α of the FFNC filter 120 is obtained by the above-described equations (1) and (2). At this time, as can be seen from equation (2), the transfer function D of the driver 140 exists on the denominator side.

[0109] Here, consider the characteristics of the FFNC filter 120 when only a full-range driver is used. FIG. 11 is a schematic diagram showing an example of the characteristics of a full-range driver and an FFNC filter corresponding to the full-range driver. In sections (a) and (b) of FIG. 11, the vertical axis represents power [dB], and the horizontal axis represents frequency.

[0110] For example, assume a full-range driver 140 having frequency characteristics as shown in section (a) of FIG. 11. Even for a full-range driver, there are few that have flat characteristics from the low range to the high range. In the example of FIG. 11(a), the driver characteristic (D) rises in the midrange and has a characteristic in which the power rapidly decreases in a predetermined high-frequency band HR in the high range. In the figure, the driver characteristic is shown as the transfer function (D).

[0111] Section (b) of FIG. 11 shows an example of the characteristics of the FFNC filter 120 corresponding to the characteristics of section (a) of this FIG. 11. In the figure, the characteristics of the FFNC filter are shown as the filter coefficient α. From the above-described formula (2), since the driver characteristics (D) are on the denominator side, the characteristics of the FFNC filter 120 have a general shape close to the inverse characteristics of the driver characteristics (D) shown in section (a), as shown in section (b). In the example of the figure, in the frequency band HR where the power drops steeply in the driver characteristics (D), the power increases steeply.

[0112] In the case of the driver characteristics (D) shown in section (a) of FIG. 11, although it is difficult for the driver 140 to reproduce the sound in the high frequency range, that is, the frequency band HR, the power in the frequency band HR of the FFNC filter 120 is large. Therefore, the driver 140 tries to forcibly reproduce the noise cancellation signal based on the output of the FFNC filter 120. As a result, the reproduced noise cancellation signal may be distorted, and instead of canceling the noise, it is conceivable that the noise is amplified.

[0113] As a countermeasure, it is possible to prevent the noise cancellation signal from being distorted by cutting the power of the high-frequency component of the FFNC filter 120. However, in this case, the higher the power is cut, the more difficult it becomes to cancel the high-frequency noise. For this reason, by using a multi-driver and dividing the band for each driver, and generating a cancellation signal for each divided frequency band, it becomes possible to cancel the noise in a wide band from the low frequency to the high frequency.

[0114] [3. Second Embodiment] 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 multi-microphone multi-driver type FF method noise canceling headphone in which two or more drivers are provided inside the housing of the headphone and two or more FF microphones are provided facing the outside of the housing respectively.

[0115] (3-1. Configuration according to the second embodiment) FIG. 12 is a schematic diagram schematically showing a vertical cross-section of the appearance of an example of a multi-microphone multi-driver type FF method noise canceling headphone 53 according to the second embodiment. Hereinafter, the "multi-microphone multi-driver type FF method noise canceling headphone 53" will be simply described as the "headphone 53". Note that FIG. 12 shows the right housing 520 among the left and right housings of the headphone 53.

[0116] Similar to the headphone 50 described with reference to FIG. 2, the headphone 53 shown in FIG. 12 has L drivers 1401, 1402,..., 140 L provided inside the housing 520. In the example of FIG. 12, with L = 3, three drivers 1401, 1402, and 140 L are provided with respect to the housing 520. The alignment direction of each of the drivers 1401, 1402, and 140 L is not limited to the vertical direction shown in FIG. 12, and may be a horizontal direction or an oblique direction.

[0117] The headphone 53 is provided with J FF microphones 1001, 1002,..., 100 J directed outward from the housing 520 with respect to the housing 520. In the example of the figure, three drivers 1401, 1402, and 140 L and three FF microphones 1001, 1002, and 100 J are provided, and each of the FF microphones 1001, 1002, and 100 J is provided at a position facing the drivers 1401, 1402, and 140 L through the housing 520. Note that the positions of each of the FF microphones 1001, 1002,..., 100 J are not limited to this example.

[0118] FIG. 13A is a schematic diagram schematically showing the configuration of an example of an acoustic output device according to the second embodiment. The configuration shown in FIG. 13A is different from the configuration shown in FIG. 3A in that, instead of the microphone amplifier 110, J FF microphones 1001, 1002,..., 100 JJ microphone amplifiers 1101, 1102, …, 110 corresponding thereto are provided respectively. J are provided.

[0119] Also, in FIG. 13A, the ADC200a and the DSP300b are configured to be capable of handling a plurality of channels of sound signals output from the J microphone amplifiers 1101, 1102, …, 110 J respectively, corresponding to those shown in FIG. 3A.

[0120] FIG. 13B is a functional block diagram of an example for explaining the function of the DSP300b according to the second embodiment. In FIG. 13B, the FFNC filter 320b includes the functions of (J×L) FFNC filters corresponding to the plurality of microphone amplifiers 1101, 1102, …, 110 J shown in FIG. 13A and the L drivers 1401, 1402, …, 140 L respectively, and outputs L noise cancellation signals corresponding to each of the drivers 1401, 1402, …, 140 L The cancellation amount control unit 321 FF includes a function of adjusting the cancellation amount for each of the L noise cancellation signals.

[0121] FIG. 14 is a diagram showing the configuration of the acoustic output device according to the second embodiment using transfer functions. Note that FIG. 14 shows only one of the configurations on the left and right sides of the headphones 53. The configuration shown in FIG. 14 includes a plurality of sets of the FF microphones and the microphone amplifiers 110 shown in FIG. 4 described above, and further includes a plurality of FFNC filters 120 for each of the plurality of sets.

[0122] Specifically, the headphones 53 are sets of the FF microphone 1001 and the microphone amplifier 1101, the FF microphone 1002 and the microphone amplifier 1102, …, the FF microphone 100 J having transfer functions M1, M2, …, M J respectively, and the microphone amplifier 110 JThe set including... Noise 20 is respectively the spatial transfer functions X1, X2,..., X J in the spaces 211, 212,..., 21 J through which are picked up by the FF microphones 1001, 1002,..., 100 J and output from the microphone amplifiers 1101, 1102,..., 110 J .

[0123] The headphones 53 each have J FFNC filters for each of the drivers 1401, 1402,..., 140 L That is, for the driver 1401, the FFNC filters 120 11 with filter coefficients α 21 , α J1 ,..., α 11 , 120 21 ,..., 120 J1 respectively. For the driver 1402, the FFNC filters 120 12 with filter coefficients α 22 , α J2 ,..., α 12 , 120 22 ,..., 120 J2 respectively. Similarly hereinafter, for the driver 140 L , the FFNC filters 120 1L with filter coefficients α 2L , α JL ,..., α 1L , 120 2L ,..., 120 JL respectively.

[0124] Note that each of the FFNC filters 120 11 ~120 JL is realized by the FFNC filter 320b in FIG. 13B.

[0125] In FIG. 14, the output of the microphone amplifier 1101 is the FFNC120 L shown first among the FFNC filters corresponding to each of the drivers 1401, 1402,..., 140 11 , 120 12 ,..., 120 1Lis input. The output of the microphone amplifier 1102 is the second FFNC120 shown among the FFNC filters corresponding to each of the drivers 1401, 1402, …, 140 L , 120 21 、120 22 、…、120 2L is input. Similarly hereinafter, the output of the microphone amplifier 110 J is the J-th FFNC120 shown among the FFNC filters corresponding to each of the drivers 1401, 1402, …, 140 L , 120 J1 、120 J2 、…、120 JL is input.

[0126] The outputs of each FFNC filter 120 11 、120 21 、…、120 J1 corresponding to the driver 1401 are added by the adder 1611 and passed to the driver amplifier 1301. The outputs of each FFNC filter 120 12 、120 22 、…、120 J2 corresponding to the driver 1402 are added by the adder 1612 and passed to the driver amplifier 1302. Similarly hereinafter, the outputs of each FFNC filter 120 L corresponding to the driver 140 1L 、120 2L 、…、120 JL are added by the adder 161 L and passed to the driver amplifier 130 L .

[0127] The configurations of each of the driver amplifiers 1301, 1302, …, 130 L and subsequent are the same as the configuration shown in FIG. 4, so the description here is omitted.

[0128] (3-2. Effects according to the second embodiment) Next, the effects according to the second embodiment will be described. It can be seen that in the multi-microphone configuration shown in FIG. 14, compared with the single-microphone configuration shown in FIG. 4 described above, the number of FFNC filters further increases, and the degree of freedom of the filter coefficient α becomes even higher. In the multi-microphone configuration, the noise cancellation performance can be improved compared with the single-microphone configuration.

[0129] FIG. 15 is a schematic diagram for explaining the outline of noise cancellation according to the second embodiment. Here, the case where noise 20 arrives from above the headphones 53 is shown. The noise 20 is first picked up by the FF microphone 1002 provided on the upper side of the housing 520 (step S10). The noise 20 further leaks into the housing 520 (step S11). Based on the noise 20 picked up by the FF microphone 1002, the headphones 53 generate a noise cancellation signal and reproduce the generated noise cancellation signal with the driver 1402 (step S12).

[0130] The noise 20 is also picked up by the FF microphone 1001 provided in the central portion of the housing 520 (step S13). Based on the noise 20 picked up by the FF microphone 1001, the headphones 53 generate a noise cancellation signal and reproduce the generated noise cancellation signal with the driver 1401 (step S14).

[0131] The cancellation signal reproduced by the driver 1402 and the cancellation signal reproduced by the driver 1401 are combined in the space inside the housing 520 to generate a wavefront (step S15). The noise 20 that leaked into the housing 520 in step S11 is canceled at the position of the eardrum 61 by the wavefront based on the cancellation signal generated in step S15.

[0132] Thus, a plurality of FF microphones 1001, 1002,..., 100 are provided in the housing 520 JBy arranging the FF microphone to pick up sound before the noise reaches the position of the eardrum 61, performing filter processing by the FFNC filter, and immediately reproducing a cancellation signal from the driver arranged near the position where the noise 20 leaks in, it is possible to improve the cancellation performance compared to a single microphone configuration. That is, a plurality of FF microphones 1001, 1002, …, 100 arranged in the housing 520 J analyze the arrival direction of the noise 20 by, and immediately reproduce a cancellation signal from the driver corresponding to the arrival direction among the drivers 1401, 1402, …, 140 L It can be considered that the performance of noise cancellation is improved by immediately reproducing a cancellation signal from the driver corresponding to the arrival direction.

[0133] (Comparison with the prior art) FIG. 16 is a schematic diagram schematically showing noise cancellation by the prior art (single microphone · single driver configuration). In the existing single microphone · single driver configuration, as shown in section (a) of FIG. 16, for the noise 20 arriving from the lateral direction of the FF microphone provided at the center of the housing 520 through the path D, a cancellation signal can be generated and reproduced before the noise 20 reaches the position of the eardrum 61. Therefore, the leakage noise that leaks in from the upper side of the housing 520 through the path E can be cancelled.

[0134] This is because the time until the noise 20 leaks into the position of the eardrum 61 through the path E is the time t N , the time for generating a cancellation signal by the FFNC filter 120 is the time t α , and the time for the cancellation sound reproduced from the driver 140 to reach the position of the eardrum 61 is the time t NC If we set it as, then t α +t NC ≦t N must always hold.

[0135] However, as shown in section (b) of FIG. 16, when the noise 20 arrives from above the housing 520, the noise 20 leaking in through the path E' reaches the position of the eardrum 61 before the cancellation signal, and t α +t NC >t N holds. Therefore, the cancellation performance deteriorates compared to the case of canceling the noise 20 from the lateral direction. Thus, as the configuration of the noise canceling headphones, by adopting the multi-microphone multi-driver type according to the second embodiment, it is possible to improve the cancellation performance compared to the existing single microphone single driver type.

[0136] [4. Third Embodiment] Next, the third embodiment will be described. In the third embodiment, as a noise canceling method, a feedback (FB) method is adopted in which a microphone provided in the housing 520 picks up the leaking noise inside the housing 520, and based on the picked up leaking noise, the leaking noise at the position of the eardrum 61 is canceled. In the third embodiment, in the multi-microphone multi-driver type, a plurality of microphones used for noise cancellation are provided inside the housing 520 as internal microphones and used as the FB method microphone (FB microphone).

[0137] (4-1. Regarding the Existing Technology) First, for easy understanding, the FB method noise cancellation by a single microphone and a single driver according to the existing technology will be described. FIG. 17 is a diagram showing the configuration of a single microphone single driver type FB method noise canceling headphone according to the existing technology using a transfer function.

[0138] The noise 20 has a spatial transfer function F FBThe leakage noise that has leaked into the housing 520 through the space 24 and the noise cancellation sound reproduced by the driver 140 and transmitted through the space 25 in the housing 520 of the spatial transfer function H are synthesized by the adder 162 in the space inside the housing 520. The sound synthesized by the adder 162 is picked up by the FB microphone 101. The sound pressure at the position of the FB microphone 101 is the sound pressure p FB is defined as.

[0139] The sound signal output from the FB microphone 101 is supplied to the microphone amplifier 111 and amplified. The transfer function including the FB microphone 101 and the microphone amplifier 111 is denoted as (M). The output of the microphone amplifier 111 is passed to the FBNC filter 121 with a filter coefficient -β for performing FB-type noise cancellation (NC).

[0140] The FBNC filter 121 generates a noise cancellation signal for generating a noise cancellation sound that cancels noise based on the input signal. The noise cancellation signal generated by the FBNC filter 121 is amplified by the driver amplifier 130 with a transfer function A and drives the driver 140 with a transfer function D. The driver 140 generates a noise cancellation sound by air vibration in response to the noise cancellation signal. The noise cancellation sound is transmitted through the space 25 from the driver 140 toward the control point (for example, the eardrum of the user wearing the headphones). At this time, as described above, the noise cancellation sound is synthesized with the noise 20 that has leaked into the housing at the adder 162 and reaches the position of the eardrum 61. As a result, the sound reaching the position of the eardrum 61 becomes a sound in which the leakage noise is canceled by the cancellation sound.

[0141] In the case of this configuration, the sound pressure p at the position of the FB microphone 101 FB is represented by the following equation (5).

[0142]

Equation

[0143] (Configuration according to the third embodiment) Next, the configuration according to the third embodiment will be described. FIG. 18 is a schematic diagram schematically showing a vertical cross-section of an appearance of an example of a multi-microphone multi-driver type FB method noise canceling headphone 54 according to the third embodiment. Hereinafter, the "multi-microphone multi-driver type FB method noise canceling headphone 54" will be simply described as the "headphone 54". Note that FIG. 18 shows the right housing 520 among the left and right housings of the headphone 54.

[0144] The headphone 54 shown in FIG. 18 has, inside the housing 520, L drivers 1401, 1402,..., 140 L as in the headphone 50 described with reference to FIG. 2. In the example of FIG. 18, with L = 3, three drivers 1401, 1402, and 140 L are provided with respect to the housing 520. The alignment direction of each of the drivers 1401, 1402, and 140 L is not limited to the vertical direction shown in FIG. 12, and may be a horizontal direction or an oblique direction.

[0145] The headphone 54 has, inside the housing 520, K FB microphones 1011, 1012,..., 101 K as shown in the figure. In the example of the figure, three drivers 1401, 1402, and 140 L and three FB microphones 1011, 1012, and 101 K are provided with respect to the housing 520, and each of the FB microphones 1011, 1012, and 101 K is provided inside the housing 520 so as to face the corresponding drivers 1401, 1402, and 140 L respectively. Note that the positions of each of the FB microphones 1011, 1012,..., 101 K are not limited to this example.

[0146] FIG. 19A is a schematic diagram schematically showing a configuration of an example of an acoustic output device according to the third embodiment. The configuration shown in FIG. 19A is different from the configuration shown in FIG. 3A in that, instead of the microphone amplifier 110, K FB microphones 1011, 1012,..., 101K K microphone amplifiers 1111, 1112, …, 111 respectively corresponding thereto K are provided.

[0147] Also, in FIG. 19A, ADC200b and DSP300c are configured to be capable of handling a plurality of channels of sound signals output from the K microphone amplifiers 1111, 1112, …, 111 corresponding to the ADC200 and DSP300a shown in FIG. 3A. K respectively.

[0148] FIG. 19B is a functional block diagram of an example for explaining the function of DSP300c according to the third embodiment. In FIG. 19B, the FBNC filter 320c includes the functions of (K×L) FBNC filters corresponding to the plurality of microphone amplifiers 1111, 1112, …, 111 shown in FIG. 19A, the L drivers 1401, 1402, …, 140 respectively, and outputs L noise cancellation signals corresponding to the respective drivers 1401, 1402, …, 140. The cancellation amount control unit 321 K and the L drivers 1401, 1402, …, 140 L respectively includes the function of adjusting the cancellation amount for each of the L noise cancellation signals. L The headphones 54 generate noise cancellation signals by the FBNC filters corresponding to the FB microphones 1011, 1012, …, 101, the FB microphones 1011, 1012, …, 102, and the respective drivers 1401, 1402, …, 140 based on the sound signals output from each of the FB microphones 1011, 1012, …, 101 respectively. By playing the generated noise cancellation signals by each of the drivers 1401, 1402, …, 140, noise cancellation by the FB method is realized. FB respectively.

[0149] The headphones 54 K respectively generate noise cancellation signals by the FBNC filters corresponding to the FB microphones 1011, 1012, …, 101, the FB microphones 1011, 1012, …, 102, and the respective drivers 1401, 1402, …, 140 based on the sound signals output from each of the FB microphones 1011, 1012, …, 101 respectively. By playing the generated noise cancellation signals by each of the drivers 1401, 1402, …, 140, noise cancellation by the FB method is realized. K and the respective drivers 1401, 1402, …, 140 L respectively. By playing the generated noise cancellation signals by each of the drivers 1401, 1402, …, 140, noise cancellation by the FB method is realized. L respectively.

[0150] FIG. 20 is a diagram showing the configuration of the acoustic output device according to the third embodiment using a transfer function. In FIG. 20, for the sake of explanation, an example in the case of using one FB microphone 101 (K = 1) is shown. Also, in FIG. 20, one of the configurations on the left and right sides of the headphones 54 is shown. The configuration shown in FIG. 20 is obtained by connecting in parallel the configurations of the FBNC filter 121, the driver amplifier 130, the driver 140, and the space 25 in the configuration according to the existing technology shown in FIG. 17, the number of drivers 1401, 1402,..., 140 L being the same as the number of L .

[0151] In FIG. 20, each noise canceling sound in which the noise canceling signal is reproduced by the drivers 1401, 1402,..., 140 L reaches the adder 163 in the housing 520 through the space transfer functions H1, H2,..., H L of the spaces 251, 252,..., 25 L respectively. Also, the noise 20 leaks into the housing 520 through the space 24 with the space transfer function F FB and reaches the adder 163 as the leaked noise. Each noise canceling sound in which the noise canceling signal is reproduced by the drivers 1401, 1402,..., 140 L is combined with the leaked noise, and the sound in which the leaked noise is canceled is picked up by the FB microphone 101.

[0152] The outputs of the FB microphone 101 are respectively passed to the FBNC filters 1211, 1212,..., 121 L with filter coefficients -β1, -β2,..., -β L . Each of the FBNC filters 1211, 1212,..., 121 L is realized by the FBNC filter 320c in FIG. 19B.

[0153] In FIG. 20, each of the FBNC filters 1211, 1212,..., 121 L is based on the output of the FB microphone 101 for each driver 1401, 1402,..., 140 LGenerate L noise cancellation signals corresponding to each. These L noise cancellation signals are respectively amplified by the corresponding driver amplifiers 1301, 1302, …, 130 L and reproduced by drivers 1401, 1402, …, 140 L respectively.

[0154] In the FB method of noise cancellation, the sound pressure p at the position of the FB microphone 101 FB should be reduced. Based on the configuration of FIG. 20, the following equation (6) is obtained.

[0155]

Equation

[0156] By transforming equation (6), the following equation (7) is obtained.

[0157]

Equation

[0158] In equation (7), in order to increase the value on the denominator side, design the filter coefficients β1, β2, …, β of each FBNC filter 1211, 1212, …, 121 L so that the sound pressure p at the position of the FB microphone 101 L approaches 0, and the noise cancellation effect can be further enhanced. Note that each filter coefficient β1, β2, …, β FB needs to be designed with caution for howling and the like. L

[0159] Compare equation (7) by the single microphone - multi - driver type FB method with equation (5) by the single microphone - single driver type FB method described above. In this case, for the multi - driver type equation (7), the filter coefficients β1, β2, …, β corresponding to each driver 1401, 1402, …, 140 L L respectively. LSince it contributes to the denominator side as a product-sum, it is possible to increase the denominator side, and the cancellation performance is improved.

[0160] FIG. 21 is a diagram showing the configuration of the acoustic output device according to the third embodiment using a transfer function. The configuration of FIG. 21 is as shown in the cross-sectional view of the appearance of the headphones 54 shown in FIG. 18, and includes K FB microphones 1011, 1012,..., 101 K in the case. In the example of FIG. 21, for the housing 520, K FB microphones 1011 to 101 K and L drivers 1401 to 140 L are provided. Also, the sound pressures at the FB microphones 1011 to 101 K are respectively the sound pressures p1, p2,..., p K .

[0161] In FIG. 21, the output of the FB microphone 1011 is input to the FBNC filters 121 11 , -β 12 ,..., -β 1L respectively having filter coefficients -β 11 , 121 12 ,..., 121 1L via the microphone amplifier 1111. The output of the FB microphone 1012 is input to the FBNC filters 121 21 , -β 22 ,..., -β 2L respectively having filter coefficients -β 21 , 121 22 ,..., 121 2L via the microphone amplifier 1112. Similarly hereinafter, the output of the FB microphone 101 K is input to the FBNC filters 121 K respectively having filter coefficients -β K1 , -β K2 ,..., -β KL via the microphone amplifier 111 K1 , 121 K2 ,..., 121 KL .

[0162] Note that each of the FBNC filters 121 11 to 121 KLis realized by the FBNC filter 320c in FIG. 19B.

[0163] In FIG. 21, the FBNC filters 121 11 , 121 21 , …, 121 K1 Each noise cancellation signal output from each of them is added by the adder 1641 and synthesized into one noise cancellation signal. The synthesized noise cancellation signal output from the adder 1641 is amplified by the driver amplifier 1301 and reproduced by the driver 1401.

[0164] The FBNC filters 121 12 , 121 22 , …, 121 K2 Each noise cancellation signal output from each of them is added by the adder 1642 and synthesized into one noise cancellation signal. The synthesized noise cancellation signal output from the adder 1642 is amplified by the driver amplifier 1302 and reproduced by the driver 1402.

[0165] Similarly hereinafter, the FBNC filters 121 1L , 121 2L , …, 121 KL Each noise cancellation signal output from each of them is added by the adder 164 L and synthesized into one noise cancellation signal. The synthesized noise cancellation signal output from the adder 164 L is amplified by the driver amplifier 130 L and reproduced by the driver 140 L .

[0166] The noise cancellation sound reproduced by the driver 1401 respectively passes through the spaces 25 11 , H 12 , …, H 1K in the housing 520 and arrives at the adder units 1631, 1632, …, 163 11 , 25 12 , …, 25 1K of the housing 520 respectively. K

[0167] The noise cancellation sounds reproduced by the driver 1402 respectively pass through the spaces 25 21 、H 22 、…、H 2K in the housing 520 and arrive at the adder units 1631, 1632, …, 163 21 、25 22 、…、25 2K in the housing 520 respectively via the spaces 25 K in the housing 520 respectively via the spaces 25

[0168] Similarly hereinafter, the noise cancellation sounds reproduced by the driver 140 L respectively pass through the spaces 25 L1 、H L2 、…、H LK in the housing 520 and arrive at the adder units 1631, 1632, …, 163 L1 、25 L2 、…、25 LK in the housing 520 respectively via the spaces 25 K in the housing 520 respectively via the spaces 25

[0169] Furthermore, noise 20 arrives at the adder unit 1631 via the space 241 of the spatial transfer function F FB1 . In the adder unit 1631, each noise cancellation sound that has arrived via the spaces 25 11 、25 21 、…、25 L1 and the leakage noise that has arrived via the space 241 are combined, and the sound canceled by each noise cancellation sound from the leakage noise is picked up by the FB microphone 1011

[0170] Furthermore, noise 20 arrives at the adder unit 1632 via the space 242 of the spatial transfer function F FB2 . In the adder unit 1632, each noise cancellation sound that has arrived via the spaces 25 12 、25 22 、…、25 L2 and the leakage noise that has arrived via the space 242 are combined, and the sound canceled by each noise cancellation sound from the leakage noise is picked up by the FB microphone 1012

[0171] Similarly, the adder 163 K further receives noise 20 through the spatial transfer function F FBK in the space 24 K The adder 163 K combines each noise cancellation sound that arrives through spaces 25 1K , 25 2K , …, 25 LK with the leakage noise that arrives through space 24 K to produce a sound that is canceled by each noise cancellation sound from the leakage noise, which is then picked up by the FB microphone 101 K .

[0172] In FIG. 21, for example, focusing on the sound pressure p1 at the FB microphone 1011, the following equation (8) can be obtained from each transfer function in FIG. 21.

[0173] [Equation]

[0174] Rearranging equation (8) gives the following equation (9).

[0175] [Equation]

[0176] Grouping the left side of equation (9) by the sound pressure p1 gives the following equation (10).

[0177] [Equation]

[0178] Grouping equation (10) by the sound pressure p1 gives the following equation (11).

[0179] [Equation]

[0180] In this equation (11), by designing each FBNC filter 121 11 ~121 1L 、121 21 ~121 2L 、and 121 K1 ~121 KL so that the denominator becomes larger, it becomes possible to cancel the leakage noise. The difference between equation (11) and the above-mentioned equation (7) based on the multi-driver single-type FB method is that the numerator side of equation (11) is the sum of the leakage noise and the FB components from FB microphones 1012, …, 101 K other than the FB microphone 1011 being focused on.

[0181] Here, for the sake of explanation, the description has been given focusing on FB1011, but the same can be derived for other FB microphones 1012~101 K as well.

[0182] [5. Fourth Embodiment] Next, a fourth embodiment of the present disclosure will be described. The fourth embodiment is an example of realizing noise cancellation by combining the FF method and the FB method in a multi-microphone multi-driver type noise canceling headphone. Hereinafter, the noise canceling method combining the FF method and the FB method will be appropriately referred to as the Dual method.

[0183] FIG. 22 is a schematic diagram schematically showing a vertical cross-section of the appearance of an example of a multi-microphone multi-driver type Dual method noise canceling headphone 55 according to the fourth embodiment. Hereinafter, the “multi-microphone multi-driver type Dual method noise canceling headphone 55” will be simply described as the “headphone 55”. Note that FIG. 22 shows the right housing 520 of the left and right housings of the headphone 55.

[0184] As shown in FIG. 22, the headphones 55 according to the fourth embodiment have a configuration that combines the headphones 53 described with reference to FIG. 12 and the headphones 54 described with reference to FIG. 18. That is, the headphones 55 have a plurality of drivers 1401, 1402, …, 140 L and a plurality of FB microphones 1011, 1012, …, 101 each used for FB (Feed-Forward) type noise cancellation. K are provided. Further, the headphones 55 have a plurality of FF microphones 1001, 1002, …, 100 each used for FF (Feed-Forward) type noise cancellation facing the outside of the housing 520. J are provided.

[0185] FIG. 23A is a schematic diagram schematically showing a configuration of an example of the acoustic output device according to the fourth embodiment. The configuration shown in FIG. 23A is a combination of the configuration of FIG. 13A described above and the configuration of FIG. 19A.

[0186] That is, the outputs of the FF microphones 1001, 1002, …, 100 J are respectively input to the ADC 200b via the microphone amplifiers 1101, 1102, …, 110 J . The ADC 200b converts each sound signal input from each of the microphone amplifiers 1101, 1102, …, 110 J into a digital sound signal and supplies it to the DSP 300d.

[0187] Similarly, the outputs of the FB microphones 1011, 1012, …, 101 K are respectively input to the ADC 200c via the microphone amplifiers 1111, 1112, …, 111 K . The ADC 200c converts each sound signal input from each of the microphone amplifiers 1111, 1112, …, 111 K into a digital sound signal and supplies it to the DSP 300d.

[0188] Fig. 23B is a functional block diagram of an example for explaining the function of a DSP 300d according to the fourth embodiment. The configuration shown in Fig. 23B is a combination of the DSP 300b shown in Fig. 13B and the DSP 300c shown in Fig. 19B. Specifically, the DSP 300d includes FF microphones 1001, 1002, ..., 100 J FFNC filter 320b and cancellation amount control section 321 FF and FB microphones 1011, 1012, ..., 101 K FBNC filter 320c and cancellation amount control section 321 FB Each output of the ADC 200b is input to an FFNC filter 320b. Also, each output of the ADC 200c is input to an FBNC filter 320c.

[0189] Fig. 24 is a diagram showing the configuration of a sound output device according to a fourth embodiment using a transfer function. Noise canceling by the FF method and noise canceling by the FB method can be controlled independently. Therefore, the configuration shown in Fig. 24 is a combination of the configuration of Fig. 14 using the multi-microphone / multi-driver type FF method noise canceling and the configuration of Fig. 21 using the multi-microphone / multi-driver type FB method noise canceling. In Fig. 24, the jth (1≦j≦J) FF microphone 100 j and Microphone Amplifier 110 j The transfer function of (M FFj ), and the kth (1≦k≦K) FB microphone 101 k and Microphone Amplifier 111 k The transfer function of (M FBk )

[0190] First, a configuration for noise canceling of the FF method in Fig. 24 will be described. The headphones 55 have a transfer function M FF1 , M FF2 , …, M FFJ A pair of the FF microphone 1001 and the microphone amplifier 1101, a pair of the FF microphone 1002 and the microphone amplifier 1102, ..., the FF microphone 100J and microphone amplifiers 110 J The set of noises 20 are respectively space transfer functions X1, X2, …, X J in spaces 211, 212, …, 21 J through which are picked up by FF microphones 1001, 1002, …, 100 J and output from microphone amplifiers 1101, 1102, …, 110 J .

[0191] The output of microphone amplifier 1101 is input to FFNC120 11 , 120 12 , …, 120 1L . Each FFNC120 11 , 120 12 , …, 120 1L generates a noise cancellation signal respectively based on the output of microphone amplifier 1101, and inputs each generated noise cancellation signal to adders 1651, 1652, …, 165 L respectively.

[0192] The output of microphone amplifier 1102 is input to FFNC120 21 , 120 22 , …, 120 2L . Each FFNC120 21 , 120 22 , …, 120 2L generates a noise cancellation signal respectively based on the output of microphone amplifier 1102, and inputs each generated noise cancellation signal to adders 1651, 1652, …, 165 L respectively.

[0193] Similarly hereinafter, the output of microphone amplifier 110 J is input to FFNC120 J1 , 120 J2 , …, 120 JL . Each FFNC120 J1 , 120 J2 , …, 120 JL is JBased on the output of , noise cancellation signals are generated respectively, and each generated noise cancellation signal is input to adders 1651, 1652, …, 165 L respectively.

[0194] Next, the configuration related to FB - type noise cancellation will be described. The headphones 55 each include a set of an FB microphone 1011 and a microphone amplifier 1111 with transfer functions M FB1 , M FB2 , …, M FBK , a set of an FB microphone 1012 and a microphone amplifier 1112, …, a set of an FB microphone 101 K and a microphone amplifier 111 K . Each of the FB microphones 1011, 1012, …, 101 K picks up the output of the adding units 1631, 1632, …, 163 K , and each sound signal picked up is output from each of the microphone amplifiers 1111, 1112, …, 111 K .

[0195] The output of the microphone amplifier 1111 is input to the FBNC filters 121 11 , 121 12 , …, 121 1L . The output of the microphone amplifier 1112 is input to the FBNC filters 121 21 , 121 22 , …, 121 2L . Similarly hereinafter, the output of the microphone amplifier 111 K is input to the FBNC filters 121 K1 , 121 K2 , …, 121 KL .

[0196] Each noise cancellation signal output from each of the FBNC filters 121 11 , 121 21 , …, 121 K1 is input to the adder 1651. The adder 1651 combines each noise cancellation signal output from each of the FFNC filters 120 11 , 120 21 , …, 120 J1 with the noise cancellation signals output from the FBNC filter 12111 、121 21 、…、121 K1 The respective noise cancellation signals output from each are combined with. The combined noise cancellation signal output from the adder 1651 is amplified by the driver amplifier 1301 and reproduced by the driver 1401.

[0197] FBNC filter 121 12 、121 22 、…、121 K2 The respective noise cancellation signals output from each are input to the adder 1652. The adder 1652 is the FFNC filter 120 12 、120 22 、…、120 J2 The respective noise cancellation signals output from each and the FBNC filter 121 12 、121 22 、…、121 K2 The respective noise cancellation signals output from each are combined with. The combined noise cancellation signal output from the adder 1652 is amplified by the driver amplifier 1302 and reproduced by the driver 1402.

[0198] Subsequently in the same manner, the FBNC filter 121 1L 、121 2L 、…、121 KL The respective noise cancellation signals output from each are input to the adder 165 L to. The adder 165 L is the FFNC filter 120 1L 、120 2L 、…、120 JL The respective noise cancellation signals output from each and the FBNC filter 121 1L 、121 2L 、…、121 KL The respective noise cancellation signals output from each are combined with. The combined noise cancellation signal output from the adder 165 L is amplified by the driver amplifier 130 L and reproduced by the driver 140 L is reproduced by.

[0199] The noise canceling sounds reproduced by the driver 1401 each reach the adding units 1631, 1632, …, 163 11 , 25 12 , …, 25 1K in the housing 520 through the spaces 25 K in the housing 520. The noise canceling sounds reproduced by the driver 1402 each reach the adding units 1631, 1632, …, 163 21 , 25 22 , …, 25 2K in the housing 520 through the spaces 25 K in the housing 520. Similarly, the noise canceling sounds reproduced by the driver 140 L each reach the adding units 1631, 1632, …, 163 L1 , 25 L2 , …, 25 LK in the housing 520 through the spaces 25 K in the housing 520.

[0200] Furthermore, noise 20 reaches each of the adding units 1631, 1632, …, 163 K through the spaces 241, 242, …, 24 K respectively.

[0201] In the adding unit 1631, each noise canceling sound that has reached through the spaces 25 11 , 25 21 , …, 25 L1 is combined with the leakage noise that has reached through the space 241, and the sound obtained by canceling the leakage noise with each noise canceling sound is picked up by the FB microphone 1011.

[0202] In the adding unit 1632, each noise canceling sound that has reached through the spaces 25 12 , 25 22 , …, 25 L2Each noise canceling sound arriving via [the relevant path] and the leakage noise arriving via space 242 are combined, and the sound canceled of the leakage noise by each noise canceling sound is picked up by the FB microphone 1012.

[0203] Similarly hereinafter, in the adder 163 K each noise canceling sound arriving via space 25 1K 、25 2K 、…、25 LK and the leakage noise arriving via space 24 K are combined, and the sound canceled of the leakage noise by each noise canceling sound is picked up by the FB microphone 101 K .

[0204] Also, the noise canceling sounds by the FF method of noise canceling reproduced by each of the drivers 1401, 1402, …, 140 L arrive at the adder 160 in the housing 520 via spaces 231, 232 and 23 L in the housing 520, respectively. The noise canceling sounds by the FF method of noise canceling are combined in the adder 160 and made into one noise canceling sound, and reach the position of the user's eardrum 61 as a sound pressure 150 of the sound pressure (p).

[0205] According to the configuration of the fourth embodiment, the residual noise in the housing 520 that could not be completely canceled by the FF method of noise canceling can be canceled by the FB method of noise canceling. Therefore, compared with the case of implementing one of the multi-microphone multi-driver type FF method of noise canceling and the multi-microphone multi-driver type FB method of noise canceling, the noise canceling performance can be further improved.

[0206] [6. Fifth Embodiment] Next, a fifth embodiment of the present disclosure will be described. The fifth embodiment enables the reproduction of immersive 3D (3-Dimension) audio content using headphones in which a plurality of drivers 140 are provided in a housing 520.

[0207] As one of this immersive 3D audio content, there is content based on object-based acoustics. In object-based acoustics, one or a plurality of audio signals serving as sound materials are regarded as one sound source (referred to as an object sound source), and meta information is added to this object sound source. Examples of the meta information added to the object sound source include position information.

[0208] For example, an object sound source including position information as meta information decodes the added meta information and reproduces it with a speaker system corresponding to object-based acoustics, thereby localizing the sound image by the object sound source at the position based on the position information, or moving the localization of the sound image on the time axis. This makes it possible to express immersive acoustics.

[0209] In headphones in which a plurality of drivers 140 are provided in a housing 520, by reproducing each object sound source, 3D audio content sound source, etc. from each driver 140, a user wearing the headphones can enjoy an immersive acoustic experience.

[0210] FIG. 25A is a schematic diagram for explaining the reproduction of an object sound source according to the fifth embodiment. In FIG. 25A, headphones 56 are provided with a plurality (three in this example) of drivers 1401, 1402, and 1403 in a housing 520. More specifically, the driver 1401 is provided substantially at the center of the housing 520, the driver 1402 is provided on the upper side of the housing 520, and the driver 1403 is provided on the lower side of the housing 520.

[0211] Object sound sources 6001, 6002, and 6003 each have position information added thereto as, for example, meta information. For example, each of the object sound sources 6001, 6002, and 6003 is input to a localization filter 1701 with filter coefficient W1, a localization filter 1702 with filter coefficient W2, and a localization filter 1703 with filter coefficient W3, such as an equalizer (EQ).

[0212] For example, the localization filter 1701 decodes the meta information added to the input object sound source 6001 and extracts the position information included in the meta information. The localization filter 1701 outputs the object sound source 6001 to the driver 1401 corresponding to the extracted position information, for example. Thereby, a reproduced sound 6011 in which the object sound source 6001 is reproduced is output from the driver 1401.

[0213] The same applies to the localization filters 1702 and 1703. That is, the localization filters 1702 and 1703 each decode the input object sound sources 6002 and 6003 and extract the position information included in the meta information, respectively. The localization filters 1702 and 1703 each output the object sound sources 6002 and 6003 to the drivers 1402 and 1403 corresponding to the extracted position information, respectively. Thereby, reproduced sounds 6012 and 6013 in which the object sound sources 6002 and 6003 are reproduced are output from the drivers 1402 and 1403, respectively.

[0214] In this way, by appropriately assigning each of the object sound sources 6001 to 6003 to each of the drivers 1401 to 1403 provided in the housing 520 based on the meta information, it is possible to reproduce, for example, immersive reproduced sounds 6011 to 6013 with each of the object sound sources 6001 to 6003.

[0215] In the above description, it has been explained that the sound localization during the reproduction of each object sound source 6001 to 6003 is fixed, but this is not limited to this example. For example, during the reproduction of each object sound source 6001 to 6003, it is also possible to move the sound localization of the reproduced sounds 6011 to 6013 by each object sound source 6001 to 6003. In this case, for example, it is conceivable to include movement information in the meta information added to each object sound source 6001 to 6003.

[0216] FIG. 25B is a schematic diagram schematically showing a state in which the sound localization is moved during the reproduction of an object sound source according to the fifth embodiment. In this example, all of the object sound sources 6001, 6002, and 6003 are reproduced from all of the drivers 140 1、 1402 and 1403, and are subjected to processing by filters that give delay and amplitude. Thereby, the movement of the reproduced sounds 6011, 6012, and 6013 of each object sound source 6001, 6002, and 6003 is realized.

[0217] In FIG. 25B, the object sound source 6001 is input to the sound localization filters 170 11 , W 12 and W 13 having filter coefficients of, respectively. The object sound source 6002 is input to the sound localization filters 170 11 , 170 12 and 170 13 having filter coefficients of, respectively. Similarly, the object sound source 6003 is input to the sound localization filters 170 21 , W 22 and W 23 having filter coefficients of, respectively. The object sound source 6003 is input to the sound localization filters 170 21 , 170 22 and 170 23 having filter coefficients of, respectively. Similarly, the object sound source 6003 is input to the sound localization filters 170 31 , W 32 and W 33 having filter coefficients of, respectively. The object sound source 6003 is input to the sound localization filters 170 31 , 170 32 and 170 33 having filter coefficients of, respectively.

[0218] Each sound localization filter 170 11 ~170 13Each decodes the meta information of the input object sound source 6001 to extract the position information and movement information. Each localization filter 170 11 ~170 13 determines the level and delay allocation to each of the drivers 1401, 1402, and 1403 of the object sound source 6001 based on the extracted position information and movement information. As a result, the reproduced sound 6011 of the object sound source 6001 can be moved within the housing 520.

[0219] Each localization filter 170 21 ~170 23 and each localization filter 170 31 ~170 33 are the same. Each localization filter 170 21 ~170 23 and each localization filter 170 31 ~170 33 each decodes the meta information of the input object sound sources 6002 and 6003 to extract the position information and movement information, and determines the level and delay allocation to each of the drivers 1401, 1402, and 1403 of the object sound sources 6002 and 6003 based on the extracted position information and movement information. As a result, similar to the above, the reproduced sound 6012 of the object sound source 6002 and the reproduced sound 6013 of the object sound source 6003 can be moved within the housing 520 respectively.

[0220] In this way, by using the headphones 56 having a plurality of drivers 1401 to 1403 in the housing 520 and outputting each object sound source 6001 to 6003 to each driver 1401 to 1403 through the localization filter 170 11 ~170 33 it is possible to provide the user with an experience as if the sound image is moving.

[0221] FIG. 26A is a schematic diagram schematically showing a configuration of an example of an acoustic output device according to the fifth embodiment. In the example of FIG. 25A, 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. An object sound source 710 corresponding to the above-described object sound sources 6001 to 6003 and the like is input to the DSP 300e.

[0222] FIG. 26B is a functional block diagram of an example for explaining the functions of the DSP 300e according to the fifth embodiment. In FIG. 26B, the DSP 300e includes a localization filter 170, a level control unit 312, and a control unit 310. The localization filter 170 realizes, for example, the localization filter 170 shown in FIG. 25B. 11 ~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 sets, for example, the localization of the object sound source 710 based on the meta information added to the object sound source 710.

[0223] The localization filter 170 generates output signals (audio signals) to be supplied to the respective drivers 140a, 140b, and 140c according to the set localization, and passes them to the level control unit 312 respectively. The level control unit 312 adjusts the levels of the respective output signals to be supplied to the respective drivers 140a, 140b, and 140c according to an instruction from the control unit 310 in response to a user operation on the operation unit 211, for example. The output signals with adjusted levels are respectively supplied to the drivers 140a, 140b, and 140c and reproduced as reproduced sounds.

[0224] FIG. 27 is a diagram showing the configuration of the acoustic output device according to the fifth embodiment using transfer functions. Each of the object sound sources 6001, 6002,..., 600 N is assumed to have transfer functions O1, O2,..., O N as acoustic characteristics, respectively.

[0225] Each object sound source 6001, 6002, …, 600 N corresponds to each of the respective drivers 1401, 1402, …, 140 L and is input into the localization filters 170 11 ~170 N1 , the localization filters 170 12 ~170 N2 , and the localization filters 170 1L ~170 NL respectively. Specifically, the object sound source 6001 is input into the localization filters 170 11 , 170 12 and 170 1L respectively. The object sound source 6002 is input into the localization filters 170 21 , 170 22 and 170 2L respectively. Similarly, the object sound source 600 N is input into the localization filters 170 N1 , 170 N2 and 170 NL respectively.

[0226] The outputs of each of the localization filters 170 11 ~170 N1 are synthesized by the adder 1661, the gain is adjusted by the gain adjustment unit 1801 having the transfer function V1, and then input into the driver amplifier 1301 and reproduced from the driver 1401. The outputs of each of the localization filters 170 12 ~170 N2 are synthesized by the adder 1662, the gain is adjusted by the gain adjustment unit 1802 having the transfer function V2, and then input into the driver amplifier 1302 and reproduced from the driver 1402. Similarly, the outputs of each of the localization filters 170 1L ~170 NL are synthesized by the adder 166 L , the gain is adjusted by the gain adjustment unit 180 L having the transfer function V L , and then input into the driver amplifier 130 L and reproduced from the driver 140 L .

[0227] Drivers 1401, 1402, …, 140 L The reproduced sounds reproduced by [drivers] are respectively the spatial transfer functions G1, G2, …, G L in the spaces 231, 232, …, 23 in the housing 520 having L reach the position of the eardrum 61 as the sound pressure 150 of the sound pressure (p) through [the spaces] and are synthesized by the adder 160 in the housing 520.

[0228] Thus, in the fifth embodiment, since a plurality of drivers 1401, 1402, …, 140 are provided in the housing 520, the degree of freedom of the localization filter 170 is increased, and thus sound image localization becomes easy. L

[0229] (6-1. Modification of the Fifth Embodiment) It is possible to combine a configuration for performing noise cancellation with the configuration for reproducing the object sound source according to the fifth embodiment described above. FIG. 28A is a schematic diagram schematically showing a configuration of an example of an acoustic output device according to a modification of the fifth embodiment.

[0230] The configuration shown in FIG. 28A incorporates the function of reproducing the object sound source 710 into the configuration shown in FIG. 23A described above. In this case, the DSP 300d shown in FIG. 23A is replaced with a DSP 300f corresponding to the processing of the object sound source, and the object sound source 710 is input to the DSP 300f instead of the audio signal 700 in FIG. 23A. Since the configurations of the other parts can be the same as those in FIG. 23A, the description thereof is omitted here.

[0231] FIG. 28B is an example of a functional block diagram for explaining the function of the DSP 300f according to a modification of the fifth embodiment. The DSP 300f shown in FIG. 28B has a configuration in which a localization filter 170 is added to the DSP 300d shown in FIG. 23B. The object sound source 710 input to the DSP 300f is input to the localization filter 170, and based on the meta information added to the object sound source 710, the drivers 1401 to 140 LThe sound localization during playback is set. At this time, the sound localization filter 170 can also adjust the set sound localization according to an instruction from the control unit 310 corresponding to a user operation on the operation unit 211, for example.

[0232] The object sound source 710 with the sound localization set by the sound localization filter 170 is passed to the adder 314 via the EQ 311 and the level control unit 312. The adder 314 synthesizes and outputs the noise cancellation signal generated by the FFNC filter 320b, the noise cancellation signal generated by the FBNC filter 320c, and the object sound source 710 with the sound localization passed from the level control unit 312.

[0233] The output of the adder 314 is converted into a digital audio signal corresponding to each driver 1401~140 L and is supplied to each driver 1401~140 via each driver amplifier 1301~130 L respectively. Each driver 1401~140 L can cancel external noise by playing the object sound source 710 and the noise cancellation sound. L L

[0234] As a result, the user wearing the headphones 55 can enjoy a high - immersion audio experience while canceling noise even outdoors.

[0235] [7. Sixth Embodiment] Next, a sixth embodiment of the present disclosure will be described. The sixth embodiment uses a plurality of FF microphones 1001, 1002,..., 100 provided in the housing 520 J to pick up noise arriving from a specific direction and play back the picked - up noise with the specific direction as the sound localization.

[0236] For example, consider a scenario where a user is wearing headphones that apply the technology described in Patent Document 2 outdoors, and a vehicle is approaching from behind the user. At this time, through beamforming processing using a plurality of FF microphones arranged outside the housing, for example, the noise of a vehicle approaching from behind is selectively picked up and reproduced from the headphone driver, and the noise from other directions is canceled, so that it is possible to prompt the user to pay attention.

[0237] At this time, in Patent Document 2, the drivers for reproducing the sound signals are one each for the L and R channels, and these drivers are arranged near the sides of the ears of the user wearing the headphones. Therefore, for example, when the noise of a vehicle approaching from behind is picked up and reproduced from the driver as described above, it is difficult for the user to completely determine that a vehicle is approaching from behind.

[0238] In the sixth embodiment, since a plurality of FF microphones 1001 to 100 J are provided in each of the left and right housings 520, it becomes possible to perform beamforming that emphasizes the sound (noise) collected from a specific direction. Further, since a plurality of drivers 1401 to 140 L are provided in each of the left and right housings 520, the picked-up sound is reproduced from the driver located in the direction corresponding to the direction from which the sound (noise) has arrived among the drivers 1401 to 140 L , or all of the drivers 1401 to 140 L are driven by signal processing to reproduce the wavefront from which the sound (noise) has arrived. As a result, the user can determine the direction from which the sound (noise) is arriving.

[0239] This sound reproduced from the driver located in the direction corresponding to the direction from which the picked-up sound (noise) has arrived, or the sound due to the wavefront from which the sound has arrived, is an acoustic control sound for controlling the acoustics inside the housing 520, and the sound signal for reproducing this sound can be considered as an acoustic control signal for the driver to reproduce the acoustic control sound.

[0240] FIG. 29 is a schematic diagram for explaining reproduction control according to the sixth embodiment. In the figure, the multi-microphone multi-driver type FF method noise canceling headphone 53 (headphone 53) according to the second embodiment is taken as an example, and a horizontal cross-section of the appearance of the left and right housings 520L and 520R of the headphone 53 is schematically shown.

[0241] The headphone 53 shown in FIG. 29 has a configuration in which the left housing 520L and the right housing 520R are connected by a headband 530. In the figure, the direction indicated by the white arrow is defined as the front in the user (head 40) wearing the headphone 53.

[0242] The housing 520L includes, inside, drivers 140L cnt 、140L fwd and driver 140L rr arranged at the central part, the front side, and the rear side, respectively. Further, the housing 520L includes, facing the outside, FF microphones 100L cent 、100L fwd and 100L rr arranged at the central part, the front side, and the rear side, respectively.

[0243] Similarly, the housing 520R includes, inside, drivers 140R cnt 、140R fwd and driver 140R rr arranged at the central part, the front side, and the rear side, respectively. Further, the housing 520R includes, facing the outside, FF microphones 100R cent 、100R fwd and 100R rr arranged at the central part, the front side, and the rear side, respectively.

[0244] The headphone 53 includes the FF microphones 100L cent 、100L fwd and 100L rr arranged in the left and right housings 520L and 520R, as well as the FF microphone 100Rcent , 100R fwd and 100R rr Based on the outputs of cent and fwd , the arrival direction of noise is detected using known beamforming techniques. The headphones 53 include drivers 140L disposed in the left and right housings 520L and 520R cnt , 140L fwd and driver 140L rr , as well as driver 140R cnt , 140R fwd and driver 140R rr Among them, the noise picked up is reproduced from the driver located in the direction corresponding to the detected arrival direction of the noise

[0245] In the example of FIG. 29, when the headphones 53 detect the noise 20L arriving from the left by, for example, beamforming (BF) 80L, the noise 20L picked up by the beamforming 80L is reproduced by the driver 140L disposed in the direction corresponding to the arrival direction of the noise 20L cnt . Similarly, when the headphones 53 detect the noise 20R arriving from the right by the beamforming 80R, the noise 20R picked up by the beamforming 80R is reproduced by the driver 140R disposed in the direction corresponding to the arrival direction of the noise 20R cnt .

[0246] Also, when the headphones 53 detect the noise 20C arriving from the rear by the beamforming 80L rr and 80R rr , the noise 20C picked up by the beamforming 80L rr and 80R rr respectively is reproduced by the drivers 140L rr and 140R rr disposed in the directions corresponding to the arrival direction of the noise 20C rr . At this time, for example, the noise 20C obtained by the beamforming 80L rr and 80R rr rr and 80R rr rr ​​Depending on the position, the noise 20C reproduced by the drivers 140L rr and 140R rr is preferably controlled for sound localization. rr Thus, while canceling the noise from the front with the user's visual information, it is possible to reproduce the noise coming from the side to the rear, which is a blind spot, with the driver. Therefore, for example, a user wearing the headphones 53 according to the sixth embodiment can easily determine that a vehicle is approaching from behind, and it is possible to ensure the safety of the user when the user uses the headphones 53 outdoors, and the problems in Patent Document 2 can be solved.

[0247] Incidentally, the noise 20C respectively picked up by the beam formings 80L

[0248] and 80R rr is the noise generated in the rear direction of the user, that is, in the direction that is a blind spot for the user. The beam formings 80L rr and 80R rr that pick up the noise generated in the direction that is a blind spot for the user are sometimes referred to as blind spot BF (beam forming). rr and 80R rr are sometimes referred to as blind spot BF (beam forming).

[0249] FIG. 30A is a schematic diagram schematically showing a configuration of an example of the acoustic output device according to the sixth embodiment. The configuration shown in FIG. 30A is different from the configuration shown in FIG. 13A described above in that the function of the DSP 300g corresponds to beam forming, and the output of the ADC 200a is branched and input to the DSP 300g. Since the other parts are the same as the configuration described with reference to FIG. 13A, the description here is omitted.

[0250] Here, the housing 520 shown in FIG. 30A represents, for example, the housing 520R among the left and right housings 520L and 520R shown in FIG. 29. Similarly, the FF microphones 1001, 1002, and 100 J respectively represent the FF microphone 100R in FIG. 29 cent, 100R fwd and 100R rr correspond to, and drivers 1401, 1402 and 140 L shall respectively correspond to driver 140R in FIG. 29 cnt , 140R fwd and 140R rr shall be as follows.

[0251] Note that ADC200a receives each audio signal based on the sound respectively picked up by each FF microphone 100L cent , 100L fwd and 100L rr , as well as FF microphone 100R cent , 100R fwd and 100R rr input thereto.

[0252] FIG. 30B is a functional block diagram of an example for explaining the function of DSP300g according to the sixth embodiment. The configuration shown in FIG. 30B is different from the configuration shown in FIG. 13B described above in that a dead angle BF (beamforming) filter 330, a localization filter 331, and a level control unit 332 are added.

[0253] The output of ADC200a is input to FFNC filter 320b and dead angle BF filter 330. Since the processing after the output of ADC200a is input to FFNC filter 320b and the processing for audio signal 700 are the same as the processing described with reference to FIG. 13B, the description thereof is omitted here.

[0254] The dead angle BF filter 330 receives each FF microphone 100L cent , 100L fwd and 100L rr input from ADC200a, as well as FF microphone 100R cent , 100R fwd and 100R rrBased on each sound signal based on the sound picked up, beamforming is performed, and noise arriving from directions that are blind spots for the user wearing the headphones 53 (such as the rear, directly to the side, etc.) is detected. The blind spot BF filter 330 is for each driver 140L cnt 、140L fwd and driver 140L rr 、as well as driver 140R cnt 、140R fwd and driver 140R rr Among them, it generates a sound signal (referred to as a noise enhancement signal) for outputting the detected noise from the driver arranged at the position corresponding to the direction from which the noise arrives.

[0255] The noise enhancement signal output from the blind spot BF filter 330 is input to the localization filter 331. The localization filter 331 has a function (such as adjustment of localization) for making the noise enhancement signal generated by the blind spot BF filter 330 sound natural to the user. The noise enhancement signal output from the localization filter 331 is controlled in level by the level control unit 332 according to an instruction from the control unit 310 corresponding to a user operation on the operation unit 211, for example. The noise enhancement signal output from the level control unit 332 is input to the adder 314, combined with the noise canceling signal and the audio signal 700, and output to the DAC 201.

[0256] Note that the range determined as a blind spot by the blind spot BF filter 330 may be made adjustable by the user. For example, the blind spot BF filter 330 sets the range determined as a blind spot according to an instruction from the control unit 310 corresponding to a user operation on the operation unit 211. If a plurality of FF microphones are arranged facing outward in each of the housings 520L and 520R of the headphones 53, the blind spot setting range can be set for any direction. When setting the blind spot BF not only for the blind spot direction but for all directions, natural external sounds as if the headphones were not worn can be provided to the user.

[0257] That is, by executing the dead angle BF, when sound from all directions is picked up by beamforming and reproduced from the driver, even when wearing headphones, external sound can be provided to the user as if not wearing headphones. For example, by setting the dead angle BF function of the headphones to be effective during walking, the user can go out safely while wearing the headphones. Also, when walking stops, the dead angle BF function is released, and the noise cancellation function is automatically enabled, for example. As a result, the user can immerse themselves in music or the like reproduced by the headphones in a state where noise cancellation is performed.

[0258] FIG. 31 is a diagram showing the configuration of the acoustic output device according to the sixth embodiment using a transfer function. In FIG. 31, the block of the transfer function related to beamforming for the housing 520R is shown. Also, in FIG. 31, each noise 201, 202,..., 20 from directions "1", "2",..., "Q" Q can be emphasized by beamforming.

[0259] Each has characteristics "N1", "N" 2、 "...", "N" Q " of the noises 201, 202,..., 20 Q is picked up by the FF microphone 1001 through the spatial transfer functions X 11 , X 21 ,..., X Q1 in the spaces 180 11 , 180 21 ,..., 180 Q1 . The noises 201, 20 2、 ... 20 Q are also picked up by the FF microphone 1002 through the spatial transfer functions X 12 , X 22 ,..., X Q2 in the spaces 180 12 , 180 22 ,..., 180 Q2 . Similarly hereinafter, the noises 201, 202,..., 20 Q are respectively the spatial transfer functions X 1J , X 2J, …, X QJ is the space 180 1J , 180 2J , …, 180 QJ is picked up by the FF microphone 100 J through.

[0260] The sound signals output from each of the FF microphones 1001, 1002, …, 100 J are respectively input into the microphone amplifiers 1101, 1102, …, 110 J . Here, the pair of the FF microphone 1001 and the microphone amplifier 1101, the pair of the FF microphone 1002 and the microphone amplifier 1102, …, the FF microphone 100 J and the microphone amplifier 110 J have transfer functions M1, M2, …, M J respectively.

[0261] Each of the sound signals output from each of the microphone amplifiers 1101, 1102, …, 110 J has a dead angle BF filter 330 with transfer functions b 11 ~b J1 , b 12 ~b J2 , …, b 1Q ~b JQ respectively. 11 ~330 J1 , 330 12 ~330 J2 , …, 330 1Q ~330 JQ is input into. These dead angle BF filters 330 11 ~330 J1 , 330 12 ~330 J2 , …, 330 1Q ~330 JQ are included in the dead angle BF filter 330 of FIG. 30B.

[0262] More specifically, the output of the microphone amplifier 1101 is input into the dead angle BF filter 330 11 , 330 12 , …, 330 1Q respectively. The output of the microphone amplifier 1102 is input into the dead angle BF filter 330 21 , 33022 to 330 2Q are respectively input thereto. Similarly hereinafter, the output of the microphone amplifier 110 J is input to the dead angle BF filters 330 J1 and 330 J2 to 330 JQ are respectively input thereto.

[0263] Each noise enhancement signal generated by each dead angle BF filter 330 11 and 330 21 to 330 J1 is synthesized by the adder 1671 and input to the localization filters 331 11 and 331 12 to 331 1L each having a transfer function w 11 and 331 12 to 331 1L are respectively input thereto. Each noise enhancement signal generated by each dead angle BF filter 330 12 and 330 22 to 330 J2 is synthesized by the adder 1672 and input to the localization filters 331 21 and 331 22 to 331 2L each having a transfer function w 21 and 331 22 to 331 2L are respectively input thereto. Similarly hereinafter, each noise enhancement signal generated by each dead angle BF filter 330 1Q and 330 2Q to 330 JQ is synthesized by the adder 167 Q and input to the localization filters 331 Q1 and 331 Q2 to 331 QL each having a transfer function w Q1 and 331 Q2 to 331 QL are respectively input thereto.

[0264] Note that the localization filters 331 11 and 331 21 to 331 QL are included in the localization filter 331 of FIG. 30B.

[0265] Each positioning filter 331 11 、331 21 、…、331 Q1 Each noise enhancement signal output from them is synthesized by the adder 1681 and the positioning is adjusted. Each positioning filter 331 12 、331 22 、…、331 Q2 Each noise enhancement signal output from them is synthesized by the adder 1682 and the positioning is adjusted. Similarly hereinafter, each positioning filter 331 1L 、331 2L 、…、331 QL Each noise enhancement signal output from them is synthesized by the adder 168 L and the positioning is adjusted. Each noise enhancement signal with adjusted positioning is respectively level-adjusted by the level control units 3321, 3322, …, 332 L included in the level control unit 332 of FIG. 30B. Each noise enhancement signal level-adjusted by each level control unit 3321, 3322, …, 332 L is supplied to the driver amplifiers 1301, 1302, …, 130 L and is respectively reproduced as noise enhancement sounds by each driver 1401, 1402, …, 140 L .

[0266] Each noise enhancement signal respectively reproduced by each driver 1401, 1402, …, 140 L is synthesized by the adder 160 in the housing 520R through the spaces 231, 232, …, 23 L in the housing 520R which are the spatial transfer functions G1, G2, …, G L and reaches the position of the eardrum 61 as the sound pressure 150 of the sound pressure p.

[0267] The noise cancellation processing described in the first to fourth embodiments can be executed independently of the noise enhancement processing according to this sixth embodiment. For example, by combining the configuration based on the noise cancellation of the multi-microphone multi-driver type FF method according to the second embodiment described with reference to FIG. 14 and the configuration shown in FIG. 31, noise from outside the dead angle can be canceled, and noise in the dead angle direction can be reproduced, ensuring the safety of the user when using outdoors or the like.

[0268] (7-1. Modification Example of the Sixth Embodiment) Next, a modification example of the sixth embodiment will be described. The modification example of the sixth embodiment is an example in which the user's speech sound is enhanced by beamforming using a plurality of FF microphones, and the position of a conversation partner who conducts a conversation with the user via communication is enhanced using a plurality of drivers.

[0269] In recent years, due to the spread of video conferencing and voice call applications, telecommuting, where work is done at home, has become increasingly implemented. When conducting a voice call conference with multiple participants during telecommuting, a headset using a microphone located at the mouth and a driver worn on one of the left and right ears is often used. In this normal headset, since the voice signal of the speaker is reproduced from one driver, it may be difficult to instantly determine who is speaking at the moment. In this case, it may interfere with the progress of the meeting or cause a situation where the content of the speech does not come in. In addition, since the microphone that picks up the voice signal of the speech is at the mouth, the user wearing it may feel a sense of pressure.

[0270] Therefore, in the modification example of the sixth embodiment, by using a multi-microphone multi-driver type headset, the voice signals of multiple speakers are arranged like object sound sources and reproduced from the corresponding drivers. This makes it easy to instantly determine who is speaking at the moment. In addition, by directing the beam to the mouth of the user wearing the headset by beamforming using multiple microphones, the voice uttered by the user wearing the headset can be clearly picked up.

[0271] FIG. 32 is a schematic diagram for explaining a voice call according to a modification of the sixth embodiment. In the example of FIG. 32, a headset 53 which is a multi-microphone multi-driver type FF method noise canceling headset is used. Note that the headset 53 shown in FIG. 32 is assumed to have further drivers mounted at front and rear positions as viewed from the user inside the housing 520 (not shown). Further, hereinafter, another user who communicates with and has a conversation with the user wearing the headset 53 is called a speaker.

[0272] Section (a) of FIG. 32 schematically shows an example of emphasizing a voice signal due to the voice generated by the user by beamforming 81 directed toward the user's mouth using, for example, FF microphones 1001 and 100 J respectively. This beamforming 81 directed toward the user's mouth is called mouth beamforming (BF).

[0273] On the other hand, sections (b) and (c) of FIG. 32 schematically show examples of controlling the sound localization of the voice by the speaker who has a conversation via communication. In section (b), it is an example in which the call voice by speaker A is reproduced by a driver 1401 disposed at the center of the housing 520 on the right side of the user. The reproduced sound 82 by the driver 1401 reaches the position of the eardrum 61. Further, for example, by controlling all the drivers provided in each housing 520 of both ears, the call voice of speaker A can be made to sound from in front of the user.

[0274] Section (c) is an example in which the call voice by speaker B is reproduced by the drivers 1401 and 140 L of the housing 520 on the right side of the user. The reproduced sound 83 reproduced by the drivers 1401 and 140 L is synthesized in the space inside the housing 520 and reaches the position of the eardrum 61. For example, by controlling the volume and phase of the reproduced sound reproduced by each driver provided in the left and right housings 520 of the user's headset 53 to be predetermined, the call voice by speaker B can be made to sound from diagonally in front of the user's right.

[0275] FIG. 33A is a schematic diagram generally showing a configuration of an example of an acoustic output device according to a modification of the sixth embodiment. The configuration shown in FIG. 33A is different in that DSP 300h is used instead of DSP 300g in the configuration shown in FIG. 30A described above, and that, for DSP 300h, instead of the audio signal 700, a speaker voice signal 720 due to the speech of a user wearing the headphone 53 is input.

[0276] FIG. 33B is a block diagram showing a configuration of an example of DSP 300h according to a modification of the sixth embodiment. The configuration of DSP 300h shown in FIG. 33B is different from the configuration of DSP 300g shown in FIG. 30B in that a mouth BF filter 333 and an EQ 334 are provided instead of the dead angle BF filter 330 and the localization filter 331, and that a speaker sound source arrangement filter 335 is provided. Further, the configuration of DSP 300h shown in FIG. 33B is also different from DSP 300g in that the output of the level control unit 332 is supplied to the control unit 310 instead of being supplied to the adder 314.

[0277] Furthermore, for DSP 300h shown in FIG. 33B, a communication unit 212 is connected to the control unit 310. The communication unit 212 communicates with an external device by wireless communication or wired communication according to the control of the control unit 310. As the wireless communication, Bluetooth (registered trademark) or the like can be applied. As the wired communication, communication via a USB (Universal Serial Bus) cable or the like can be considered.

[0278] In FIG. 33B, the speaker voice signal 720 is, for example, a voice signal acquired from speakers A, B, etc. by communication by the communication unit 212. The speaker voice signal 720 is input to the speaker sound source arrangement filter 335. The speaker sound source arrangement that determines where the speech of the communication partner speaker can be heard is, for example, indicated by the user's operation of the operation unit 211. The control unit 310 can realize this by reading, from the memory 210, filter coefficients adjusted so that the speech of the speaker can be heard from the position as if it were indicated, and writing them to the speaker sound source arrangement filter 335 in response to this instruction.

[0279] The speaker voice signal 720 is thus set for localization and the like by the speaker sound source placement filter 335 in which the filter coefficients are written, and is passed to the adder 314 via the EQ 311 and the level control unit 312.

[0280] The mouth BF filter 333 has the same function as the dead angle BF filter 330 described above. That is, the mouth BF filter 333 performs beamforming based on each sound signal based on the sound picked up by each FF microphone 1001, 1002,... 100 of the left and right casings 520 input from the ADC 200a, and selectively acquires the voice signal by the voice coming from the mouth part of the user wearing the headphone 53. The voice signal output from the mouth BF filter 333 is adjusted in sound quality by the EQ 334 and passed to the control unit 310 via the level control unit 332. The control unit 310 transmits the voice signal passed from the level control unit 332 to the partner's playback device, for example, by communication by the communication unit 212. The EQ 334 emphasizes, for example, the frequency band of the human voice and cuts extra frequency bands such as the low band and the high band. J Based on each sound signal based on the sound picked up by each FF microphone 1001, 1002,... 100 of the left and right casings 520 input from the ADC 200a, beamforming is performed, and the voice signal by the voice coming from the mouth part of the user wearing the headphone 53 is selectively acquired. The voice signal output from the mouth BF filter 333 is adjusted in sound quality by the EQ 334 and passed to the control unit 310 via the level control unit 332. The control unit 310 transmits the voice signal passed from the level control unit 332 to the partner's playback device, for example, by communication by the communication unit 212. The EQ 334 emphasizes, for example, the frequency band of the human voice and cuts extra frequency bands such as the low band and the high band.

[0281] The adder 314 synthesizes the noise canceling signal passed from the cancellation amount control unit 321 FF and the speaker voice signal 720 passed from the level control unit 312, and outputs the result to the DAC 201.

[0282] As described above, in the modification of the sixth embodiment, the acquisition of the user's speaking voice by beamforming, the reproduction of the speaker voice signal 720 whose arrangement is appropriately set by the speaker sound source placement filter 335, and the noise canceling by the FF method can be executed simultaneously. Therefore, it is possible to concentrate on the voice signals by the speeches of speakers A and B, and it becomes possible to easily hear the speeches by speakers A and B.

[0283] [8. Seventh Embodiment] Next, a seventh embodiment of the present disclosure will be described. The seventh embodiment is an example in which a plurality of drivers and a plurality of FB microphones are provided inside a housing 520, and personal differences of a user wearing the headphones are corrected.

[0284] More specifically, in a state where the user wears the headphones, the acoustic characteristics inside the housing are measured by playing the sound reproduced by each driver and picking up the sound by each FB microphone, and based on the picked-up sound, the acoustic characteristics (in-ear characteristics) inside the housing are measured. Then, based on the measurement results, various parameters that affect the in-ear characteristics are corrected.

[0285] In the FB method of noise cancellation using an FB microphone, for example, in the case of the multi-microphone multi-driver type FB method of noise cancellation, it can be seen from the above-described formula (11) that the transfer function H from the driver to the FB microphone position contributes to the cancellation performance. This transfer function H often differs between the time of FBNC filter design and the actual use by the user, and furthermore, since it varies depending on the individual differences of the user and the wearing state of the headphones, it has been difficult to provide optimal noise cancellation by the FB method.

[0286] Therefore, by arranging a plurality of microphones inside the headphone housing and reproducing a measurement signal from each driver, the in-ear characteristics T for each user can be measured. As the measurement signal here, a sine wave, random noise, a music signal, a TSP (Time Stretched Pulse) signal, etc. can be applied.

[0287] FIG. 34 is a schematic diagram schematically showing an example of a method for measuring the in-ear characteristics T according to the seventh embodiment. Here, taking the headphones 54 having a plurality (three in this case) of drivers 1401, 1402, and 140 L and a plurality (three in this example) of FB microphones 1011, 1012, and 101 L provided in the housing 520 relative to these drivers 1401, 1402, and 140 K as an example, the description will be given.

[0288] Also, in FIG. 34, for the sake of explanation, driver 1402 is shown as driver #1, driver 1401 is shown as driver #2, and driver 140 L is shown as driver #3, respectively. Also, here, for the sake of explanation, FB microphone 1011 is FB microphone #2, FB microphone 1012 is FB microphone #1, and FB microphone 101 K is FB microphone #3.

[0289] For example, first, as shown in section (a) of FIG. 34, a measurement signal is reproduced by driver #1, and the reproduced sound is picked up by each of FB microphones #1, #2, and #3. Based on each of the picked-up sounds, the in-ear characteristics T 11 , T 12 and T 13 are measured. Next, as shown in section (b), a measurement sound is reproduced by driver #2, and the reproduced sound is picked up by each of FB microphones #1, #2, and #3. Based on each of the picked-up sounds, the in-ear characteristics T 21 , T 22 and T 23 are measured. Finally, as shown in section (c), a measurement sound is reproduced by driver #3, and the reproduced sound is picked up by each of FB microphones #1, #2, and #3. Based on each of the picked-up sounds, the in-ear characteristics T 31 , T 32 and T 33 are measured.

[0290] Thus, when there are three drivers #1, #2, and #3 and three FB microphones #1, #2, and #3 in the housing 520, by combination, the in-ear characteristics T 11 ~T 13 , the in-ear characteristics T 21 ~T 23 , and the in-ear characteristics T 31 ~T 33 can be measured. Each of the in-ear characteristics T 11 ~T 13 , T 21 ~T 23 , and the in-ear characteristics T 31 ~T 33By correcting it so as to approach the transfer function H at the time of designing the FBNC filter 320c, individual differences among users wearing the headphones 53 can be corrected.

[0291] FIG. 35 is a schematic diagram schematically showing a configuration of an example of an acoustic output device according to the seventh embodiment. Since the configuration shown in this FIG. 35 is the same as the configuration of FIG. 19A described above except for the DSP 300i, descriptions of parts other than the DSP 300i will be omitted.

[0292] Note that in FIG. 35, portions deeply related to the measurement of the in-ear characteristics T are extracted and shown, and configurations related to the reproduction of the audio signal 700 and the like are appropriately omitted. That is, the DSP 300i includes, for example, the FBNC filter 320c shown in FIG. 19B and the cancellation amount control unit 321 FB and. The DSP 300i further includes, for example, the EQ 311 shown in FIG. 19B and the level control unit 312.

[0293] The DSP 300i is connected to the memory 210, the operation unit 211, and the communication unit 212.

[0294] 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.

[0295] The measurement signal generation unit 340 generates a measurement signal for measuring the in-ear characteristics T. As described above, a sine wave, random noise, a music signal, a TSP signal, or the like can be applied as the measurement signal. The control unit 310 instructs the measurement signal generation unit 340 to generate and output the measurement signal, for example, in response to a user operation on the operation unit 211. The measurement signal generation unit 340 generates and outputs a measurement signal in response to this instruction. The measurement signal generation unit 340 generates a measurement signal, for example, by reading measurement signal information for generating a measurement signal such as waveform data previously stored in the memory 210.

[0296] The measurement signal output from the measurement signal generation unit 340 is adjusted to a predetermined level by the level control unit 312 and passed to the DAC 201. The DAC 201 converts the passed digital measurement signal into an analog measurement signal and supplies it to each of the driver amplifiers 1301, 1302, and 103 L respectively. The driver amplifiers 1301, 1302, and 130 L drive the drivers 1401, 1402, and 140 L respectively to reproduce the measurement signal.

[0297] At this time, the control unit 310 can control, for example, the driver amplifiers 1301, 1302, and 130 L to select which of the drivers 1401, 1402, and 140 L will reproduce the measurement signal.

[0298] The measurement sound reproduced by the driver 1401, 1402, or 140 L is picked up by the FB microphones 1011, 1012, and 101 K respectively, and each is made into a measurement sound signal and input to the ADC 200b via the microphone amplifiers 1111, 1112, and 111 K . The ADC 200b converts each of the measurement sound signals input from the microphone amplifiers 1111, 1112, and 111 K into a digital measurement sound signal and outputs it.

[0299] Each measurement sound signal output from the ADC 200b is acquired by the measurement data acquisition unit 350 and passed to the correction value calculation unit 351. The correction value calculation unit 351 obtains the in-ear characteristic T based on each measurement sound signal acquired by the measurement data acquisition unit 350. The correction value calculation unit 351 calculates a correction value for the FBNC filter 320c (not shown) for correcting the FBNC filter based on the obtained in-ear characteristic T. For example, the correction value calculation unit 351 calculates the filter coefficients -β 11 ~121 KL of each FBNC filter 121 11 ~-β KLCalculate the FBNC filter correction value for correction. The correction value calculation unit 351 passes the calculated FBNC filter correction value to the FBNC filter correction unit 352.

[0300] Based on the FBNC filter correction value passed from the correction value calculation unit 351, the FBNC filter correction unit 352 corrects each parameter such as the filter coefficient -β of the FBNC filter 320c. Each parameter of the corrected FBNC filter 320c is stored in the memory 210 via the control unit 310.

[0301] Note that the memory 210 can store a plurality of parameters of the FBNC filter 320c. For example, measurements can be performed for each user using the headphones 53, or for each usage environment (usage location, presence or absence of hats and glasses, hairstyle, etc.) of a certain user, and the parameters can be stored respectively. The user can specify the parameters corresponding to the situation during the use of the headphones 53 by a user operation on the operation unit 211. The control unit 310 writes the specified parameters into the FBNC filter 320c.

[0302] FIG. 36 is a flowchart showing an example of the measurement process according to the seventh embodiment. For example, when an instruction to start measurement is issued by the control unit 310, 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.

[0303] In the next step S102, the measurement signal generation unit 340 outputs the measurement signal generated in step S101. The measurement signal output by the measurement signal generation unit 340 is supplied to the driver amplifiers 1301, 1302, and 130 L via the level control unit 312 and the DAC 201, and is reproduced as a measurement sound signal.

[0304] In the next step S103, the driver amplifiers 1301, 1302, or 130 LThe measurement sound obtained by reproducing the measurement sound signal is picked up by the FB microphones 1011, 1012, and 101 K Each of the FB microphones 1011, 1012, and 101 K Based on the measurement sound picked up by each, each measurement sound signal is acquired by the measurement data acquisition unit 350 and passed to the correction value calculation unit 351.

[0305] In step S104, the correction value calculation unit 351 calculates the in-ear characteristic T lk based on each measurement sound signal passed from the measurement data acquisition unit 350. Here, the in-ear characteristic T lk is the transfer function from the l-th driver among the drivers 1401, 1402, and 140 L to the k-th FB microphone among the FB microphones 1011, 1012, and 101 K For example, the processes of steps S102 to S104 described above are repeatedly executed while switching the driver that reproduces the measurement sound among the drivers 1401, 1402, and 140 L When the measurement by the combination of the drivers 1401, 1402, and 140

[0306] and the FB microphones 1011, 1012, and 101 L is completed and each in-ear characteristic T k is calculated, the process proceeds to step S105. In step S105, the control unit 310 calculates an FBNC filter correction value for correcting the FBNC filter 320c based on each in-ear characteristic T lk calculated by the correction value calculation unit 351 in step S104, and stores each parameter of the FBNC filter 320c corrected by the calculated FBNC filter correction value in the memory 210. lk Thus, in the seventh embodiment, a plurality of drivers 1401, 1402, and 140

[0307] provided in the housing 520, and a plurality of FB microphones 1011, 1012, and 101 L and a plurality of FB microphones 1011, 1012, and 101 KThe in-ear characteristics T are calculated using these, and each parameter of the FBNC filter 320c is corrected based on the calculation result. Therefore, the performance of noise cancellation by the FB method can be improved.

[0308] (8-1. First Modification Example of the Seventh Embodiment) Next, a first modification example of the seventh embodiment will be described. The first modification example of the seventh embodiment corrects the equalizer for correcting the sound signal based on the measured in-ear characteristics T with respect to the above-described seventh embodiment.

[0309] FIG. 37 is a schematic diagram schematically showing a configuration of an example of an acoustic output device according to a first modification example of the seventh embodiment. Since the configuration shown in this FIG. 37 is the same as the configuration of FIG. 35 described above except for the DSP 300j, the description of parts other than the DSP 300j will be omitted.

[0310] In addition, in FIG. 37, parts deeply related to the measurement of the in-ear characteristics T are extracted and shown, and configurations related to the reproduction of the audio signal 700 and the like are appropriately omitted. That is, the DSP 300j includes, for example, the FBNC filter 320c shown in FIG. 19B and the cancellation amount control unit 321 FB and. The DSP 300j further includes, for example, the EQ 311 shown in FIG. 19B and the level control unit 312.

[0311] In FIG. 37, the DSP 300j has a playback EQ correction unit 353 added to the above-described DSP 300i. The correction value calculation unit 351 calculates an FBNC filter correction value for correcting the FBNC filter 320c (not shown) and an EQ correction value for correcting the EQ 311 (not shown) based on each measured sound signal acquired by the measurement data acquisition unit 350.

[0312] The EQ correction value calculated by the correction value calculation unit 351 is passed to the playback EQ correction unit 353. The playback EQ correction unit 353 corrects each parameter of the EQ 311 (not shown) based on the passed EQ correction value. Each parameter of the corrected EQ 311 is stored in, for example, the memory 210.

[0313] In this way, by correcting each parameter of the EQ 311 that corrects the audio signal 700 based on the measured in-ear characteristics T, the characteristics of the audio signal 700 reproduced by the headphones 54 can be optimized according to the individual characteristics (such as the shape of the ear). As a result, for example, in the correction of the low frequency range of the audio signal 700, an effect of improving the sound quality according to individual differences or the individual's wearing state can be expected.

[0314] (8-2. Second Modification of the Seventh Embodiment) Next, a second modification of the seventh embodiment will be described. The second modification of the seventh embodiment is an example in which, in the headphones 55 shown in FIG. 22, in addition to correcting the parameters of the FBNC filter 320c and the EQ 311, the parameters of each FFNC filter 320b are corrected, where a plurality of drivers 1401 to 140 L and a plurality of FB microphones 1011 to 101 K are provided inside the housing 520, and a plurality of FF microphones 1001 to 100 J are provided facing the outside of the housing 520.

[0315] FIG. 38 is a schematic diagram schematically showing a configuration of an example of an acoustic output device according to the second modification of the seventh embodiment. In this FIG. 38, the plurality of FF microphones 1001 to 100 J included in the headphones 55 are omitted from description to avoid complexity.

[0316] The measurement sound obtained by reproducing the measurement signal by the driver 1401, 1402, or 140 L is picked up by the FB microphones 1011, 1012, and 101 K and is respectively made into measurement sound signals and input to the microphone amplifiers 1111, 1112, and 111K It is input to the ADC200b via []. The ADC200b converts each measurement sound signal input from each microphone 1111, 1112, and 111 K into a digital measurement sound signal and outputs it.

[0317] Each measurement sound signal output from the ADC200b is input to the DSP300k, acquired by the measurement data acquisition unit 350, and passed to the correction value calculation unit 351. The correction value calculation unit 351 obtains the in-ear characteristic T based on each measurement sound signal acquired by the measurement data acquisition unit 350. Based on the obtained in-ear characteristic T, the correction value calculation unit 351 calculates an FBNC filter correction value for correcting an FBNC filter 320c (not shown) and an FFNC filter correction value for correcting an FFNC filter 320b (not shown). The correction value calculation unit 351 passes the calculated FBNC filter correction value and FFNC filter to the FF / FBNC filter correction unit 354.

[0318] The FF / FBNC filter correction unit 354 corrects each parameter such as the filter coefficient -β of the FBNC filter 320c based on the FBNC filter correction value passed from the correction value calculation unit 351. Also, the FF / FBNC filter correction unit 354 corrects each parameter such as the filter coefficient α of the FFNC filter 320b based on the FFNC filter correction value passed 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.

[0319] Here, as can be seen from the above-described equation (2), noise cancellation by the FF method requires the spatial transfer function G of the space from the driver to the eardrum position. This is the same for noise cancellation by the multi-driver type FF method. The spatial transfer function G at the time of designing the FFNC filter 320b is different from the spatial transfer function G in the state where the headphones are actually worn by the user, and furthermore, since the shape of the ear is different for each user, variations occur in the spatial transfer function G. As a result, it becomes difficult to provide optimal cancellation performance for the user.

[0320] As described with reference to FIG. 34, inside the housing 520, there are three drivers 1401, 1402, and 140 L and three FB microphones 1011, 1012, and 101 K When provided, the user's in-ear characteristics T can be measured at nine points. By obtaining a correction coefficient C such that the error between this in-ear characteristic T and the spatial transfer function G as the reference in-ear characteristic at the time of FFNC filter design is minimized and reflecting it in each parameter of the FFNC filter 320b, an improvement in cancellation performance can be expected.

[0321] FIG. 39 is a flowchart showing an example of the correction value calculation process according to the second modification of the seventh embodiment. In step S200, the correction value calculation unit 351 reads, for example, a reference characteristic bar H lk pre-stored in the memory 210. Note that " bar " indicates a symbol "~ (tilde)" placed above the next character (in this case, "H"). At the same time, the correction value calculation unit 351 reads, for example, the in-ear characteristic T lk stored in the memory 210 at the previous measurement from the memory 210.

[0322] The processes of the next step S210 to step S212, the processes of step S220 to step S222, and the processes of step S230 to step S232 may be executed in parallel or sequentially.

[0323] In step S210, the correction value calculation unit 351 calculates a correction coefficient C bar H lk for correcting each parameter of the FFNC filter 320b based on the reference characteristic lk and the in-ear characteristic T FFlk . The correction value calculation unit 351 passes the calculated correction coefficient C FFlk to the FF / FBNC filter correction unit 354. In the next step S211, the FF / FBNC filter correction unit 354 uses the correction coefficient C FFlkBased on this, 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.

[0324] In step S220, the correction value calculation unit 351 calculates a correction coefficient C bar H lk and the in-ear characteristic T lk for correcting each parameter of the FBNC filter 320c. The correction value calculation unit 351 passes the calculated correction coefficient C FBlk to the FF / FBNC filter correction unit 354. In the next step S221, the FF / FBNC filter correction unit 354 updates the filter coefficient β of the FBNC filter 320c based on the correction coefficient C FBlk . In the next step S222, the control unit 310 stores the updated filter coefficient β in the memory 210. FBlk

[0325] In step S230, the correction value calculation unit 351 calculates a correction coefficient C bar H lk and the in-ear characteristic T lk for correcting each parameter of the EQ 311 for playing the audio signal 700. The correction value calculation unit 351 passes the calculated correction coefficient C EQlk to the playback EQ correction unit 353. In the next step S231, the playback EQ correction unit 353 updates each parameter of the EQ 311 based on the correction coefficient C EQlk . In the next step S232, the control unit 310 stores each updated parameter of the EQ 311 in the memory 210. EQlk

[0326] ​​For example, when the control unit 310 plays an audio signal 700 or the like through the headphones 55, it applies the filter coefficients α and β stored in the memory 210 and each parameter of the EQ 311 to the FFNC filter 320b, the FBNC filter 320c, and the EQ 311, respectively. As a result, the user wearing the headphones 55 can listen to the reproduced sound of, for example, the audio signal 700 with the sound quality corrected according to the user's characteristics by the EQ 311 and the noise canceled in a state adapted to the user's characteristics.

[0327] (8-3. Third Modification of the Seventh Embodiment) Next, a third modification of the seventh embodiment will be described. The third modification of the seventh embodiment is an example in which, in headphones provided with a plurality of drivers and a plurality of FB microphones inside the housing 520, the fitting state (referred to as fitting determination) when the user wears the headphones is determined.

[0328] Here, the description will be given assuming that the configuration shown in FIG. 35 is applied as the configuration of the acoustic output device.

[0329] In noise-canceling headphones, the wearing comfort of the headphones has a great influence on the noise-canceling effect. For example, if the wearing comfort of the headphones is poor and there is a large gap between the head 40 of the user wearing the headphones and the ear pads 510, external noise may leak in through the gap, and the noise-canceling effect may be reduced. As a simple example, from FIG. 1 and Equation (2) described above, the wearing comfort of the headphones is extremely important because it affects the leakage noise that leaks into the inside of the headphone housing through the space of the spatial transfer function F of the noise and the spatial transfer function G from the driver to the eardrum position.

[0330] For example, in the headphones 54 in which a plurality of drivers 1401 to 140 are arranged in the housing 520, as described with reference to FIG. 18 L and a plurality of FB microphones 1011 to 101 K and, in the headphones 54 in which each driver 1401 to 140L Reproduce the measurement signal. Each FB microphone 1011~101 K Pick up the measurement sound in which the measurement signal is reproduced, and the ear canal characteristics T calculated based on the measurement sound signal output from each FB microphone 1011~101 K By analyzing, the details of the wearing condition of the headphones 54 can be determined. lk

[0331] FIG. 40 is a schematic diagram for explaining the wearing determination according to the third modification of the seventh embodiment. In the example of FIG. 40, the wearing property of the headphones 54 worn by the user on the head 40 is poor, and a state in which a gap is formed between the head 40 and the upper ear pad 510 of the housing 520 is shown. In this state, the measurement signals are reproduced one by one from each driver 1401~140 of the headphones 54, and the measurement sound in which the measurement signal is reproduced is picked up by each FB microphone 1011~101 L By doing so, the position where noise leaks in is detected. K

[0332] In FIG. 40, for the sake of explanation, the driver 1402 is shown as driver #1, the driver 1401 is shown as driver #2, and the driver 140 L is shown as driver #3 respectively. Also, here, for the sake of explanation, the FB microphone 1011 is set as FB microphone #2, the FB microphone 1012 is set as FB microphone #1, and the FB microphone 101 K is set as FB microphone #3.

[0333] Section (a) of FIG. 40 shows an example of reproducing the measurement signal with driver #1. In this case, the reproduced measurement sound will leak out in the direction opposite to the wavefront direction of the measurement sound by driver #1. When analyzing the low-frequency power in the measurement sound picked up by each FB microphone #1~#3, it can be seen that the power p 13 from driver #1 to FB microphone #3 is the largest, and the power p 11 from driver #1 to FB microphone #1 is the smallest. The power p 12 from driver #1 to FB microphone #2 is in the middle of the two.

[0334] Section (b) shows an example of reproducing a measurement signal with Driver #2. In this case, the reproduced measurement sound will leak out in a direction obliquely upward with respect to the wavefront direction of the measurement sound by Driver #2. Analyzing the low-frequency power in the measurement sound picked up by each of the FB microphones #1 to #3, it can be seen that the power p from Driver #2 to FB microphone #3 23 is the largest, and the power p from Driver #2 to FB microphone #1 21 is the smallest. The power p from Driver #2 to FB microphone #2 22 is intermediate between the two.

[0335] Section (c) shows an example of reproducing a measurement signal with Driver #3. In this case, the reproduced measurement sound will leak out upward with respect to the wavefront direction of the measurement sound by Driver #3. Analyzing the low-frequency power in the measurement sound picked up by each of the FB microphones #1 to #3, it can be seen that the power p from Driver #3 to FB microphone #3 33 is the largest, and the power p from Driver #3 to FB microphone #1 31 is the smallest. The power p from Driver #3 to FB microphone #2 32 is intermediate between the two.

[0336] From the above, it can be seen that the power p from Driver #1 to FB microphone #1 11 and the power p from Driver #2 to FB microphone #1 21 and the power p from Driver #3 to FB microphone #1 31 are each small, and it can be determined that the wearing condition near the upper part of the ear of the headphones 54 is poor.

[0337] FIGS. 41A and 41B are diagrams showing an example of a notification method for notifying a user wearing the headphones 54 of the wearing condition of the headphones 54 determined as described above, which is applicable to the eighth embodiment.

[0338] FIG. 41A is an example of notifying the result of the wearing determination using a portable terminal device 900 such as a smartphone or a tablet personal computer. For example, the terminal device 900 pre-installs an application program corresponding to this determination result notification.

[0339] Note that the terminal device 900 can apply a general configuration as an information processing device capable of communication. For example, it includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage device such as a flash memory, a communication interface (I / F) for performing wireless communication, an input device for receiving user operations, and a display device. The CPU controls the overall operation according to a program stored in the storage device. The terminal device 900 is not limited to this and may be a device dedicated to the headphone 54. The above-mentioned application program is supplied from an external network or the like via the communication I / F, for example, and installed in the terminal device 900.

[0340] The control unit 310 notifies the terminal device 900 of the wearing state determination result obtained as described above through the communication of the communication unit 212. The terminal device 900 causes a screen for displaying the notification content to be displayed on the display 901 of the terminal device 900 by the above-mentioned application program. In this example, a state in which the headphones are worn on the head is schematically shown in the area 910 of the display 901, and a portion with poor wearing state is highlighted by a frame line 911. Further, a message 912 specifically indicating whether the wearing state of the part is poor ("It seems that the wearing state of the upper part of the ear is poor") is further displayed on the display 901.

[0341] In this example, buttons 920 and 921 are arranged at the lower part of the display 901. Button 920 is a button for ending the display of the determination result, for example. Button 921 is a button for instructing remeasurement of the headset 54 in order to perform the wearing state determination again. The terminal device 900 transmits an instruction for remeasurement to the headset 54 in response to an operation on button 921. This instruction is received by the communication unit 212 and passed to the control unit 310 in the headset 54. The control unit 310 controls each part of the headset 54 according to the passed instruction and executes remeasurement and wearing state determination.

[0342] FIG. 41B is an example of notifying the result of the wearing state determination by the sound reproduced by the headset 54. In the example of FIG. 41B, a voice message 922 ("It seems that the wearing state of the upper part of the ear is not good") indicating the wearing state determination result is being reproduced by the driver 1401.

[0343] For example, the control unit 310 generates a voice message 922 using voice data indicating the wearing state determination result obtained as described above. For example, a message indicating an assumed wearing state determination result is stored in advance in the memory 210. The control unit 310 reads out a message corresponding to the wearing state determination result from the memory 210, converts the read message into voice data using, for example, a known voice reading technology, etc., and generates the voice message 922. This is not the only way; the message may also be stored in the memory 210 as voice data.

[0344] The control unit 310 supplies the generated voice message 922 to each driver amplifier 1301 - 130 L via the DAC 201 and causes each driver 1401 - 140 L to reproduce it. In this case, the voice message 922 may be reproduced by at least one of the drivers 1401 - 140 L . It is also possible to reproduce the voice message 922 from a driver close to the position determined to have a poor wearing state among the drivers 1401 - 140 L .

[0345] Here, when only one FB microphone is provided in the housing 520, it is difficult to identify the part with poor wearing condition. In the third modification of the seventh embodiment, since a plurality of FB microphones 1011 to 101 K are provided in the housing 520, it is possible to determine the detailed wearing state.

[0346] [9. Eighth Embodiment] Next, the eighth embodiment of the present disclosure will be described. The eighth embodiment is an example in which the functions according to the above-described embodiments are settable as operation modes in response to user operations.

[0347] Among the functions described in each embodiment, the functions that can be set as operation modes are as follows, for example. (1) Noise canceling function by FF method, FB method, or Dual method. This is the function corresponding to the first to fourth embodiments. (2) Reproduction function with high sense of presence by 3D audio signal (object sound source). This is the function corresponding to the fifth embodiment and is a function that can be realized by a multi-driver type headphone. (3) Function of picking up and reproducing noise in a specific direction. This is the function corresponding to the sixth embodiment and is a function that can be realized by a multi-FF microphone multi-driver type headphone. (4) Beamforming function for the mouth area. This is the function corresponding to the modification of the sixth embodiment and is a function that can be realized by a multi-FF microphone multi-driver type headphone. (5) Beamforming function for blind spots. This is the function corresponding to the sixth embodiment and is a function that can be realized by a multi-FF microphone multi-driver type headphone. (6) Correction function for individual differences during wearing. This is the function corresponding to the seventh embodiment and its first and second modifications, and is a function that can be realized by a multi-FB microphone multi-driver type headphone. (7) Wearing determination function. This is the function corresponding to the third modification of the seventh embodiment and is a function that can be realized by a multi-FB microphone multi-driver type headphone.

[0348] Figure 42 is a schematic diagram showing a configuration example of an acoustic output device according to the eighth embodiment. The configuration shown in Figure 42 is capable of executing the above-described functions (1) to (7) respectively. The headphones 55 are those described with reference to Figure 22, and a plurality of FF microphones 1001 to 100 J are provided facing the outside of the housing 520, and a plurality of drivers 1401 to 140 L and a plurality of FB microphones 1011 to 101 K are provided inside the housing 520.

[0349] In Figure 42, the microphone amplifiers 1101 to 110 J corresponding to the respective FF microphones 1001 to 100 J are collectively shown as the microphone amplifier 110, and the microphone amplifiers 1111 to 111 K corresponding to the respective FB microphones 1011 to 101 K are collectively shown as the microphone amplifier 111. Similarly, the driver amplifiers 1301 to 130 L corresponding to the respective drivers 1401 to 140 L are collectively shown as the driver amplifier 130.

[0350] The ADC 200d converts each audio signal supplied from the microphone amplifiers 110 and 111 into a digital audio signal and inputs it to the DSP 300l.

[0351] The DSP 300l 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.

[0352] The filter unit 360 includes the above-described filters (including the FFNC filter 320b, the FBNC filter 320c, the dead angle BF filter 330, the localization filter 331, and the mouth BF filter 333). Further, the filter unit 360 includes an EQ 334, a level control unit 332, a cancellation amount control unit 321 FF and 321 FBIt includes. Further, the filter unit 360 includes a localization filter 170 that sets the localization of the object sound source 710. The filter unit 360 can be configured to perform these functions individually or in a predetermined combination under the control of the control unit 310.

[0353] The correction processing unit 361 includes a measurement data acquisition unit 350, a correction value calculation unit 351, an FF / FBNC filter correction unit 354, and a reproduction EQ correction unit 353. The correction processing unit 361 can be configured to perform these functions individually, in plural, or in a predetermined combination under the control of the control unit 310.

[0354] Here, the EQ 311, the level control unit 312, and a part of the filter unit 360 (for example, the localization filter 170) realize functions for reproducing an audio signal, and execute processing on the input signal 730 including the audio signal 700, the object sound source 710, and the speaker voice signal 720.

[0355] In the eighth embodiment, each of the functions (1) to (7) described above can be set from the terminal device 900 that can communicate via the communication unit 212. FIG. 43 is a schematic diagram showing an example of a function setting screen displayed on the display 901 of the terminal device 900 applicable to the eighth embodiment. This function setting screen is displayed on the display 901 when the application program installed in the terminal device 900 is executed.

[0356] In FIG. 43, the area 930 of the display 901 is an area for setting during reproduction of the audio signal 700 or the object sound source 710 by the headphones 55, during noise cancellation, etc. The area 931 is an area for performing measurement processing using a measurement signal in the headphones 55.

[0357] In the example of FIG. 43, for area 930, check boxes 930a to 930e are provided for input by performing an operation of putting a check mark inside the frame. When the check box 930a is checked, execution of noise cancellation by the FF method is set. When the check box 930b is checked, execution of noise cancellation by the FB method is set. When the check box 930c is checked, it is set to play a 3D audio signal (object sound source 710). When the check box 930d is checked, execution of mouth beamforming (BF) is set. Also, when the check box 930e is checked, execution of dead angle beamforming (BF) is set. Multiple of these check boxes 930a to 930e can be checked simultaneously.

[0358] Also, in area 931, buttons 931a and 931b for input according to an operation are provided. Button 931a is a button for instructing execution of correction of individual differences of the user according to the seventh embodiment or the first and second modification examples of the seventh embodiment. According to the operation of this button 931a, a measurement sound signal is reproduced in the headphones 55, and measurement of the in-ear characteristic T is started. Button 931b is a button for instructing execution of wearing determination of the headphones 55 according to the third modification example of the seventh embodiment. According to the operation of this button 931b, a measurement sound signal is reproduced in the headphones 55, and leakage of the reproduced sound to the outside of the housing 520 is measured.

[0359] The terminal device 900 transmits an input to the check boxes 930a to 930e and an instruction according to the operations of the buttons 931a and 931b to the headphones 55. In the headphones 55, this instruction is received by the communication unit 212 and passed to the control unit 310. The control unit 310 controls the filter unit 360, the measurement signal generation unit 340, the correction processing unit 361, etc. according to the passed instruction to execute the operation of the instruction.

[0360] Thus, in the eighth embodiment, since the execution of each function in the headphones 55 can be instructed from the terminal device 900, the user can easily set the execution of each function in the headphones 55 alone or in combination.

[0361] [10. Ninth Embodiment] Next, a ninth embodiment of the present disclosure will be described. In the ninth embodiment, in the headphones provided with a plurality of drivers 1401 to 140 L in the housing 520, an example is shown in which one or more of these drivers 1401 to 140 L are operated and used as a microphone.

[0362] It is known that a dynamic driver (speaker) can be used as a microphone. This is because the mechanism of electricity, vibration, and sound radiation of the dynamic driver is just the reverse of the mechanism of sound incidence, vibration, and electricity of the microphone.

[0363] FIGS. 44A and 44B are schematic diagrams schematically showing an example of using a driver as a microphone according to the ninth embodiment.

[0364] FIG. 44A is a schematic diagram schematically showing a vertical cross-section of an appearance of an example of a multi-driver type headphone provided with a plurality of drivers inside the housing 520 applicable to the ninth embodiment. The headphones 57 shown in FIG. 44A are provided with a plurality (three in this example) of drivers 1401, 1402, and 1403 inside the housing 520.

[0365] In FIGS. 44A and 44B, for the sake of explanation, the driver 1402 is shown as driver #1, the driver 1401 is shown as driver #2, and the driver 1403 is shown as driver #3, respectively.

[0366] FIG. 44B is a diagram schematically showing an example in which one of the three drivers 1401 to 1403 provided in the housing 520 is used as a function of an original driver (speaker), and the other two are used as microphones. In this case, for example, a measurement signal is reproduced by the driver used for the original function, and the measurement sound reproduced by the measurement signal is picked up by the two drivers used as microphones.

[0367] In section (a) of FIG. 44B, a measurement signal is reproduced by driver #1, and the reproduced measurement sound is picked up using driver #2 and #3 as microphones, respectively. Based on the measurement sound signals picked up by driver #2 and #3, the in-ear characteristics T 12 from driver #1 to driver #2 13 and the in-ear characteristics T

[0368] from driver #1 to driver #3 can be calculated. 21 In section (b) of FIG. 44B, a measurement signal is reproduced by driver #2, and the reproduced measurement sound is picked up using driver #1 and #3 as microphones, respectively. Based on the measurement sound signals picked up by driver #1 and #3, the in-ear characteristics T 23 from driver #2 to driver #1

[0369] and the in-ear characteristics T 31 from driver #2 to driver #3 can be calculated. 32 Furthermore, in section (c) of FIG. 44B, a measurement signal is reproduced by driver #3, and the reproduced measurement sound is picked up using driver #1 and #2 as microphones, respectively. Based on the measurement sound signals picked up by driver #1 and #2, the in-ear characteristics T

[0370] from driver #3 to driver #1 12 and the in-ear characteristics T 13 from driver #3 to driver #2 21 can be calculated. 23 These calculated in-ear characteristics T 31 and T32 Based on this, for example, it is possible to perform correction of individual differences according to the above-described seventh embodiment and its first and second modified examples. Further, by further measuring the power of the measured sound that has been picked up, it is also possible to perform wearing determination according to the third modified example of the seventh embodiment.

[0371] FIG. 45 is a flowchart showing an example of a process for measuring the in-ear characteristic T using a driver as a microphone according to the ninth embodiment. The process according to this flowchart is started with the user wearing the headphones 57.

[0372] Here, it is assumed that L drivers are provided in the housing 520, and the driver (l) indicates a driver sequentially selected from the L drivers in a loop. Whether or not to use the driver as a microphone is controlled by the driver amplifier corresponding to the driver according to an instruction from the control unit 310. Also, here, the configuration of FIG. 35 in the seventh embodiment is applied as the acoustic output device. Further, when the driver is used as a microphone, the signal output by sound collection from the driver is supplied to the DSP 300i via the microphone amplifiers 1111 to 111 K and the ADC 200b.

[0373] In step S300, the control unit 310 selects the driver (l) to be used as the original function from the L drivers. In the next step S301, the control unit 310 sets the drivers other than the driver (l) selected in step S300 among the L drivers to a microphone mode in which they can be used as microphones.

[0374] 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 measurement signal to be reproduced by the driver (l) set in step S300. In the next step S303, among the L drivers, the drivers other than the driver (l) pick up the measurement sound in which the measurement signal is reproduced by the driver (l). Each measurement sound signal output by the drivers other than the driver (l) after picking up the measurement sound is supplied to the DSP300i. The DSP300i calculates, for example, the in-ear characteristic T based on each supplied measurement sound signal.

[0375] In the next step S304, the control unit 310 determines whether or not the reproduction of the measurement signal by the driver (l) and the picking up of the reproduced measurement sound by the other drivers are completed. If the control unit 310 determines that it is not completed (step S304, "No"), the process returns to step S302.

[0376] If the control unit 310 determines that it is completed (step S304, "Yes"), the process proceeds to step S305. In step S305, the control unit 310 performs a fader process on the measurement sound in which the measurement sound signal is reproduced. For example, the control unit 310 causes the level control unit 312 to attenuate the level of the measurement signal output from the measurement signal generation unit 340 over a predetermined time and fade out the reproduced sound. Thereby, it is possible to avoid a situation where the reproduced sound suddenly cuts off and suppress the discomfort of the user wearing the headset 57.

[0377] In the next step S306, the control unit 310 determines whether or not the measurement signal has been reproduced from all the drivers in the housing 520. If the control unit 310 determines that the measurement signal has been reproduced from all the drivers in the housing 520 (step S306, "Yes"), the series of processes according to this flowchart is terminated.

[0378] On the other hand, when the control unit 310 determines that measurement signals are not being reproduced from all the drivers within the housing 520, that is, when there is a driver among the L drivers within the housing 520 that has not yet reproduced a measurement signal (step S306, "No"), the process returns to step S300. Then, the control unit 310 selects a driver (l) that reproduces a measurement signal from among the L drivers within the housing 520 that have not yet reproduced a measurement signal (step S300), and executes the processes from step S301 onward.

[0379] According to the ninth embodiment, measurement of the in-ear characteristics T and the like are executed by using some of the plurality of drivers within the housing 520 as microphones. Thereby, compared with the case of arranging a plurality of microphones within the housing 520, it becomes possible to reduce the space within the housing 520, and it becomes possible to miniaturize the headphones. Further, since a plurality of microphones are not provided within the housing 520, it becomes possible to reduce costs.

[0380] Note that the effects described in this specification are merely examples and are not limiting, and there may be other effects.

[0381] Note that the present technology can also adopt the following configurations. (1) A housing, One or more outward-facing microphones provided on the housing and facing the outside of the housing, Two or more drivers provided inside the housing and each generating acoustic control sound based on an acoustic control signal, An acoustic output device comprising the same. (2) The two or more drivers include a first driver and a second driver, The first driver is arranged such that the sound wave radiated therefrom travels in a first direction, The second driver is arranged such that the sound wave radiated therefrom travels in a second direction different from the first direction, The acoustic output device according to (1) above. (3) further comprising a signal processing unit that generates the acoustic control signal, the signal processing unit, has a first filter for generating the acoustic control signal based on the sound picked up by the first microphone including the one or more outward microphones, the acoustic output device according to (2) above. (4) the signal processing unit, further has a second filter for generating the acoustic control signal based on the sound picked up by the second microphone including the one or more outward microphones, the acoustic output device according to (3) above. (5) the first microphone is provided on the housing to pick up sound in a third direction, the second microphone is provided to pick up sound in a fourth direction different from the third direction, the acoustic output device according to (4) above. (6) the signal processing unit, based on the sounds picked up by the first microphone and the second microphone respectively, 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, the acoustic output device according to (5) above. (7) further comprising one or more internal microphones provided inside the housing, the signal processing unit, further has a third filter for generating the acoustic control signal based on the sound picked up by the third microphone including the one or more internal microphones, the acoustic output device according to any one of (3) to (6) above. (8) the signal processing unit, further has a fourth filter for generating the acoustic control signal based on the sound picked up by the fourth microphone including the one or more internal microphones, The acoustic output device according to (7) above. (9) The third microphone is provided to pick up sound in the fifth direction inside the housing. The fourth microphone is provided to pick up sound in a sixth direction different from the fifth direction inside the housing. The acoustic output device according to (8) above. (10) 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 each of the sound picked up by the third microphone and the sound picked up by the fourth microphone. The acoustic output device according to (9) above. (11) The signal processing unit sets the localization of the emphasized sound based on the sound picked up by the outward microphones respectively provided in the housings respectively worn on the left and right sides of the listener, and based on the set localization, generates output signals for each of the two or more drivers respectively provided in the housings respectively worn on the left and right sides of the listener for the emphasized sound. The acoustic output device according to (10) above. (12) The signal processing unit measures the ear canal characteristics of the listener based on the sound picked up by the one or more internal microphones from the sound generated by the two or more drivers with the housing worn by the listener. The acoustic output device according to any one of (7) to (11) above. (13) The signal processing unit uses at least one of the two or more drivers as a microphone, and uses this microphone instead of the one or more internal microphones to measure the ear canal characteristics of the listener. The acoustic output device according to (12) above. (14) The signal processing unit determines the wearing condition of the housing with respect to the listener according to the measured ear canal characteristics The acoustic output device according to (12) above (15) The signal processing unit uses the microphone using the driver in place of the one or more internal microphones, and determines the wearing condition of the housing with respect to the listener according to the measured ear canal characteristics The acoustic output device according to (13) above (16) further includes a communication unit that communicates with a terminal device The signal processing unit transmits the determination result of the wearing condition to the terminal device by the communication unit The acoustic output device according to (14) or (15) above (17) further includes a communication unit that communicates with a terminal device The signal processing unit is set with a function of executing according to an instruction received from the terminal device by the communication unit The acoustic output device according to any one of (3) to (16) above (18) The signal processing unit plays back an object sound source by the two or more drivers generates an output signal when playing back the object sound source to each of the two or more drivers based on meta information added to the object sound source The acoustic output device according to any one of (3) to (17) above (19) The acoustic control sound includes a noise canceling sound that cancels the sound leaking from the outside of the housing into the inside of the housing The acoustic output device according to any one of (1) to (18) above (20) The acoustic control sound includes an emphasized sound that emphasizes the sound generated in a specific direction outside the housing The acoustic output device according to any one of (1) to (19) above. (21) The processor causes two or more drivers provided inside a housing in which one or more microphones are provided facing outward to generate acoustic control sounds based on acoustic control signals, respectively. A method for controlling an acoustic output device.

Description of reference numerals

[0382] 20, 20L, 20R, 20C rr , 201, 202, 20 Q Noise 20 BIG High sound pressure noise 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 , 25 22 , 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 40 Head 50, 51, 52, 53, 54, 55, 56, 57 Headphones 60 External auditory canal 61 Eardrum 80L, 80R, 80L rr , 80R rr , 81 Beamforming 82, 83 Reproduced sound 100, 1001, 1002, 100 J , 100L fwd , 100Lcent , 100L rr , 100R fwd , 100R cent , 100R rr FF microphone 101, 1011, 1012, 101 K FB microphone 110, 1101, 1102, 110 J , 111, 1111, 1112, 111 K Microphone amplifier 120, 1201, 1202, 120 L , 120 11 , 120 21 , 120 J1 , 120 12 , 120 22 , 120 J2 , 120 1L , 120 2L , 120 JL , 320a, 320b FFNC filter 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 130, 1301, 1302, 130 L , 130a, 130b, 130c Driver amplifier 140, 1401, 1402, 1403, 140 L , 140 tw , 140 mid , 140 wf , 140a, 140b, 140c, 140L fwd , 140L cnt , 140L rr , 140R fwd , 140R cnt , 140R rr Driver 150 Sound pressure 160, 162, 163, 1631, 1632, 163 KAddition unit 1611,1612,161 L ,1641,1642,164 L ,1651,1652,165 L ,1661,1662,166 L ,1671,1672,167 Q ,1681,1682,168 L ,313,314 Adder 170,1701,1702,1703,170 11 ,170 12 ,170 13 ,170 21 ,170 22 ,170 23 ,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 1801,1802,180 L Gain adjustment unit 200,200a,200b,200c,200d ADC 201 DAC 210 Memory 211 Operation unit 212 Communication unit 300a,300b,300c,300d,300e,300f,300g,300h,300i,300j,300k,300l DSP 310 Control unit 311,334 EQ 312,332,3321,3322,332 L Level control unit 321 FF ,321FB Cancellation amount control unit 330,330 11 ,330 21 ,330 J1 ,330 12 ,330 22 ,330 J2 ,330 1Q ,330 2Q ,330 JQ Dead angle BF filter 333 Mouth BF filter 335 Speech sound source arrangement filter 340 Measurement signal generation unit 350 Measurement data acquisition unit 351 Correction value calculation unit 352 FBNC filter correction unit 353 Reproduction EQ correction unit 354 FF / FBNC filter correction unit 360 Filter unit 361 Correction processing unit 400,401,402,403,404,405,406,407,407’,408,409,410 Wavefront 510 Ear pad 520,520L,520R Housing 530 Headband 6001,6002,6003,600 N ,710 Object sound source 6011,6012,6013 Reproduced sound 700 Audio signal 720 Speaker voice signal 730 Input signal 900 Terminal device 901 Display 910,930,931 Region 911 Frame line 912 Message 920,921,931a,931b Button 922 Voice message 930,931 Region 930a,930b,930c,930d,930e Check box

Claims

1. A housing, one or more outward microphones provided on the housing and facing the outside of the housing, two or more drivers provided inside the housing, each generating acoustic control sound based on an acoustic control signal, a signal processing unit that generates the acoustic control signal, one or more internal microphones provided inside the housing, An acoustic output device comprising: The two or more drivers include a first driver and a second driver, The first driver is arranged at a different position from the second driver, The signal processing unit, generates the acoustic control signal when reproducing the object sound source to each of the two or more drivers based on meta information added to the object sound source, measures the ear characteristics of the listener based on the sound picked up by the one or more internal microphones from the sound generated by the two or more drivers when the listener wears the housing, uses at least one of the two or more drivers as a microphone and uses the microphone instead of the one or more internal microphones for measuring the ear characteristics, Acoustic output device.

2. The first driver is arranged such that the radiated sound wave travels in a first direction, The second driver is arranged such that the radiated sound wave travels in a second direction different from the first direction, The acoustic output device according to claim 1.

3. The signal processing unit, has a first filter for generating the acoustic control signal based on the sound picked up by a first microphone included in the one or more outward microphones, The acoustic output device according to claim 1.

4. The signal processing unit, further has a second filter for generating the acoustic control signal based on the sound picked up by a second microphone included in the one or more outward microphones, The acoustic output device according to claim 3.

5. The first microphone is provided on the housing to pick up sound in a third direction, The second microphone is provided on the housing to pick up sound in a fourth direction different from the third direction, The acoustic output device according to claim 4.

6. The signal processing unit, Based on the sounds respectively picked up by the first microphone and the second microphone, 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 are generated. The acoustic output device according to claim 5.

7. The signal processing unit further has a third filter for generating the acoustic control signal based on the sound picked up by a third microphone included in the one or more internal microphones. The acoustic output device according to claim 1.

8. The signal processing unit further has a fourth filter for generating the acoustic control signal based on the sound picked up by a fourth microphone included in the one or more internal microphones. The acoustic output device according to claim 7.

9. The third microphone is provided to pick up the sound in a fifth direction inside the housing, and the fourth microphone is provided to pick up the sound in a sixth direction different from the fifth direction inside the housing. The acoustic output device according to claim 8.

10. 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 each of the sound picked up by the third microphone and the sound picked up by the fourth microphone. The acoustic output device according to claim 9.

11. The signal processing unit sets the localization of the emphasized sound based on the sounds picked up by the outward microphones respectively provided in the housings respectively worn on the left and right sides of the listener, and based on the set localization, generates output signals for each of the two or more drivers respectively provided in the housings respectively worn on the left and right sides of the listener for the emphasized sound. The acoustic output device according to claim 10.

12. The signal processing unit judges the wearing condition of the housing with respect to the listener according to the measured ear canal characteristics. The acoustic output device according to claim 1.

13. The signal processing unit judges the wearing condition of the housing with respect to the listener according to the measured ear canal characteristics by using the microphone using the driver instead of the one or more internal microphones. The acoustic output device according to claim 1.

14. further comprising a communication unit that communicates with the terminal device, the signal processing unit, is set to have a function of executing according to an instruction received from the terminal device by the communication unit, The acoustic output device according to claim 1.

15. The acoustic control sound, includes a noise cancellation sound that cancels sound leaking from the outside of the housing into the inside of the housing, The acoustic output device according to claim 1.

16. The acoustic control sound, includes an emphasized sound that emphasizes sound generated in a specific direction outside the housing, The acoustic output device according to claim 1.

17. A processor, generates an acoustic control signal, and causes two or more drivers provided inside a housing in which one or more microphones are provided facing outward to generate acoustic control sounds based on the acoustic control signal respectively, A method for controlling an acoustic output device, comprising: the two or more drivers include a first driver and a second driver, the first driver is arranged at a position different from that of the second driver, one or more internal microphones are provided inside the housing, the processor, generates the acoustic control signal when reproducing the object sound source to each of the two or more drivers based on meta information added to the object sound source, measures the ear characteristics of the listener based on the sound picked up by the one or more internal microphones from the sound generated by the two or more drivers with the housing worn by the listener, uses at least one of the two or more drivers as a microphone and uses the microphone instead of the one or more internal microphones for measuring the ear characteristics, A method for controlling an acoustic output device.

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