Sound field correction device, sound field correction method and program

Abstract

To effectively suppress the influence of differences in arrival times of sounds from multiple speakers.SOLUTION: A sound field correction device according to an embodiment measures audio output from multiple speakers at a predetermined listening position, and includes an output control unit that controls the multiple speakers to output audio in different frequency bands for each speaker, a receiving unit that receives information about the output audio, a calculation unit that performs frequency analysis processing for each of the multiple speakers using the received audio information and calculates the time difference between when the audio output from the multiple speakers reaches the listening position, and a correction unit that corrects the output timing of the multiple speakers on the basis of the time difference.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a sound field correction device, a sound field correction method, and a program. [Background technology]

[0002] In an audio device that outputs sound from multiple speakers, audio delays can occur due to the difference in the timing at which the sound output from each speaker reaches the listening position. One method for solving this problem is to capture test sounds output from the speakers with a microphone, measure the time it takes for each speaker to reach the microphone, and calculate the delay time based on the measured times. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 6-013292 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-330500 Summary of the Invention [Problem to be solved by the invention]

[0004] The above calculation method requires measurements to be taken for each speaker and the delay time to be calculated, which takes time.

[0005] An object of the present invention is to provide a sound field correction device, a sound field correction method, and a program that effectively suppress the influence of differences in arrival times of sounds from multiple speakers. [Means for solving the problem]

[0006] The sound field correction device of the embodiment is a sound field correction device that measures audio output from multiple speakers at a predetermined listening position, and is equipped with an output control unit that controls the multiple speakers to output audio with different frequency bands for each speaker, a receiving unit that receives information about the output audio, a calculation unit that performs frequency analysis processing for each of the multiple speakers using the received audio information and calculates the time difference between when the audio output from the multiple speakers reaches the listening position, and a correction unit that corrects the output timing of the multiple speakers based on the time difference. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram illustrating an example of a hardware configuration of an audio device according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of a functional configuration of the sound field correction device according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of a method for calculating an impulse response according to an embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of a measurement signal according to the embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of a TSP signal and an inverse TSP signal in one frequency band according to the embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of a calculation result of an impulse response according to the embodiment. [Figure 7] FIG. 7 is a flowchart illustrating an example of processing in the sound field correction device according to the embodiment. [Figure 8] FIG. 8 is a diagram showing an example of a measurement method according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the following, exemplary embodiments of the sound field correction device 5 of the present invention and the sound field correction device 5 for performing the sound field correction method will be disclosed.

[0009] 1 is a block diagram showing an example of the hardware configuration of an audio device 1 according to an embodiment. The audio device 1 is a device capable of outputting sound from multiple speakers, and may be, for example, a stereo, a video playback device, a recording device, a television, a home theater system, etc.

[0010] The acoustic device 1 according to this embodiment includes a sound field correction device 5, a first speaker 31A, a second speaker 31B, a third speaker 31C, and a remote control 41.

[0011] The sound field correction device 5 performs sound field correction processing to reduce the difference in arrival time between the sounds output from each speaker by optimizing the output timing of the sounds AS1, AS2, and AS3 output from the first speaker 31A, the second speaker 31B, and the third speaker 31C, respectively, depending on the positional relationship between the first speaker 31A, the second speaker 31B, the third speaker 31C, and the user's listening position. In this embodiment, the listening position is assumed to be the position where the remote control 41 is located.

[0012] The sound field correction device 5 of this embodiment includes a CPU (Central Processing unit) 11, a memory 12, a storage 13, a user I / F (Interface) 14, a communication I / F 15, an audio decoder 21, an audio input ADC (Analog to Digital Converter) 22, a DSP (Digital Signal Processor) 23, a first delay circuit 25A, a second delay circuit 25B, and a third delay circuit 25C, and these components are connected to each other so that they can communicate with each other via a communication bus 20.

[0013] The CPU 11 executes predetermined arithmetic and control processes in accordance with programs (including firmware, application software, etc.) stored in the memory 12, etc. The memory 12 is a main storage device including RAM (Random Access Memory), ROM (Read Only Memory), etc., and functions as a program storage area, a work area for the CPU 11, etc. The storage 13 is an auxiliary storage device including non-volatile memory such as an SSD (Solid State Drive) or HDD (Hard Disk Drive), and enables writing and reading of various data. The user I / F 14 is a device that enables receiving input from a user and outputting information to the user, and may be, for example, a display, input buttons, etc. The communication I / F 15 is a device that enables communication with other electronic devices connected via a predetermined communication network. In this embodiment, the communication I / F 15 establishes wireless communication with the remote control 41 in accordance with a predetermined standard.

[0014] The audio decoder 21 is a device that converts audio data recorded on a predetermined medium (e.g., a CD, a DVD, a Blu-ray (registered trademark) disc, a removable medium, etc.), audio data included in broadcast waves, audio data acquired from a network such as a CSP (Communications Service Provider), etc., into a digital signal in a format that can be output from the first speaker 31A, the second speaker 31B, and the third speaker 31C. The audio input ADC 22 is a device that converts an analog audio signal input from an external device into a digital signal.

[0015] The DSP23 is a processor that performs predetermined processing on digital signals corresponding to sounds output from the first speaker 31A, the second speaker 31B, and the third speaker 31C, and generates audio signals for the sounds AS1, AS2, and AS3 to be listened to, as well as audio signals for the first test sound TS1, the second test sound TS2, and the third test sound TS3 described below.

[0016] The first delay circuit 25A is a circuit that delays the output timing of the audio AS1 output from the first speaker 31A in accordance with a correction signal (delay signal) output from the CPU 11. The second delay circuit 25B is a circuit that delays the output timing of the audio AS2 output from the second speaker 31B in accordance with a correction signal output from the CPU 11. The third delay circuit 25C is a circuit that delays the output timing of the audio AS3 output from the third speaker 31C in accordance with a correction signal output from the CPU 11.

[0017] The remote control 41 is a device that can be operated by a user who wants to listen to the sounds AS1, AS2, and AS3, and includes a microphone 45, a wireless modulation circuit 46, and a transmitter 47. The microphone 45 is a device that converts captured sounds into electrical signals (analog signals). The wireless modulation circuit 46 is a circuit that modulates the electrical signals generated by the microphone 45 into signals (digital signals) in a format that allows wireless communication in accordance with a predetermined standard. The transmitter 47 is a device that transmits the signals modulated by the wireless modulation circuit 46 to the sound field correction device 5.

[0018] In addition to the above, the remote control 41 is provided with buttons and the like for accepting user operations, but a description thereof will be omitted here. Also, in the present embodiment, a configuration in which the microphone 45 is provided in the remote control 41 is exemplified, but the microphone 45 may be an independent device.

[0019] The sound field correction device 5 of this embodiment is a sound field correction device 5 that measures audio output from multiple speakers at a predetermined listening position, and includes an output control unit that controls the multiple speakers to output audio in different frequency bands for each speaker, a receiving unit 103 that receives information about the output audio, a calculation unit 105 that uses the received audio information to perform frequency analysis processing for each speaker and calculates the time difference between when the audio output from the multiple speakers reaches the listening position, and a correction unit 106 that corrects the output timing of the speakers based on the time difference.

[0020] Specifically, when performing the sound field correction process, the sound field correction device 5 according to this embodiment simultaneously outputs the first test sound TS1, the second test sound TS2, and the third test sound TS3 from the first speaker 31A, the second speaker 31B, and the third speaker 31C, respectively. The TSP signals in the frequency band of the first test sound TS1, the TSP signals in the frequency band of the second test sound TS2, and the TSP signals in the frequency band of the third test sound TS3 are all in different frequency bands.

[0021] A microphone 45 mounted on the remote control 41 acquires a complex sound including a first test sound TS1, a second test sound TS2, and a third test sound TS3, and a transmitter 47 transmits an acoustic signal St of the complex sound acquired by the microphone 45 to the sound field correction device 5.

[0022] The sound field correction device 5 analyzes the frequency components contained in the acoustic signal St received from the remote control 41. That is, it performs frequency analysis by multiplying each TSP signal by its corresponding inverse TSP signal. Then, it obtains the maximum amplitude value from the calculated impulse response. Based on the analysis results, it calculates the arrival time t1 of the first test sound TS1 from the first speaker 31A to the microphone 45, the arrival time t3 of the second test sound TS2 from the second speaker 31B to the microphone 45, and the arrival time t2 of the third test sound TS3 from the third speaker 31C to the microphone 45, and calculates the time difference between the arrival times from each speaker to the microphone 45. It also calculates the amplitude of each speaker. Specifically, it calculates the time difference Δt1 between the first speaker 31A and the second speaker 31B, the time difference Δt2 between the second speaker 31B and the third speaker 31C, and the time difference Δt3 between the first speaker 31A and the third speaker 31C.

[0023] Then, based on the calculated time difference, the sound field correction device 5 performs a process of correcting at least one of the output timing of the sound AS1 from the first speaker 31A, the output timing of the sound AS2 from the second speaker 31B, and the output timing of the sound AS3 from the third speaker 31C, i.e., a delay process for controlling the first delay circuit 25A, the second delay circuit 25B, or the third delay circuit 25C. Furthermore, based on the calculated amplitude difference, the sound field correction device 5 corrects the amplitude of at least one speaker to approach a target amplitude difference. The test sound may be the output sound.

[0024] When the third speaker 31C is not provided, the sound field correction device 5 according to this embodiment simultaneously outputs the first test sound TS1 and the second test sound TS2 from the first speaker 31A and the second speaker 31B, respectively, during the sound field correction process. The TSP signal in the frequency band of the first test sound TS1 and the TSP signal in the frequency band of the second test sound TS2 are in different frequency bands.

[0025] A microphone 45 mounted on the remote control 41 acquires a complex sound including a first test sound TS1 and a second test sound TS2, and a transmitter 47 transmits an acoustic signal St of the complex sound acquired by the microphone 45 to the sound field correction device 5.

[0026] The sound field correction device 5 analyzes the frequency components contained in the acoustic signal St received from the remote control 41. That is, it performs frequency analysis by multiplying each TSP signal with its corresponding inverse TSP signal. Then, it obtains each maximum amplitude value from the calculated impulse response and calculates the time difference Δt1 between the arrival time t1 of the first test sound TS1 from the first speaker 31A to the microphone 45 and the arrival time t3 of the second test sound TS2 from the second speaker 31B to the microphone 45 based on the analysis results. It also calculates the volume difference between the speakers from the magnitude of the amplitude.

[0027] Then, based on the calculated time difference Δ1, the sound field correction device 5 executes a process of correcting at least one of the output timing of the sound AS1 from the first speaker 31A and the output timing of the sound AS2 from the second speaker 31B, i.e., a process of controlling the first delay circuit 25A or the second delay circuit 25B. Also, based on the calculated amplitude difference, the sound field correction device 5 corrects the amplitude of at least one speaker to approach a target amplitude difference. The test sound may be the output sound.

[0028] Fig. 2 is a block diagram showing an example of the functional configuration of a sound field correction device 5 according to an embodiment. The sound field correction device 5 according to this embodiment includes an audio output control unit 101, a test sound output control unit 102, a receiving unit 103, a recording unit 104, a calculation unit 105, a correction unit 106, a memory 12, and an audio decoder 21. These functional units 101 to 106, 12, and 21 can be realized by cooperation between hardware and software (programs) as exemplified in Fig. 1. Furthermore, at least some of these functional units 101 to 106, 12, and 21 may be realized by dedicated hardware (circuits, etc.).

[0029] The sound field correction device 5, for example, controls the test sound output control unit 102 of the DSP 23 to output an audio signal St from each speaker. Then, the receiving unit 103 of the communication I / F 15 receives the audio signal St. The audio signal St is then stored in the recording unit 104 of the storage 13. The calculation unit 105 of the CPU 11 performs frequency analysis on the acquired TSP signal. The calculation unit 105 calculates the time difference between the arrival of each speaker at the listening position. The correction unit 106 of the DSP 23 controls the delay circuits 25A, 25B, and 25C to correct the output timing of each speaker. Then, the audio output control unit 101 of the DSP 23 receives a digital signal from the audio decoder 21 and controls each speaker to output audio. The calculation unit 105 acquires the target amplitude for each speaker from the memory 12, and the correction unit 106 corrects the amplitude to be output from each speaker. Note that the correspondence between each functional component and hardware component is merely an example.

[0030] The audio output control unit 101 is, for example, a function executed by the DSP 23. The audio output control unit 101 performs control so that audio AS1, AS2, and AS3 to be listened to are output from the first speaker 31A, the second speaker 31B, and the third speaker 31C, respectively.

[0031] The test sound output control unit 102 is, for example, a function executed by the DSP 23. When the sound field correction process is being executed, the test sound output control unit 102 controls the first speaker 31A to output a first test sound TS1, the second speaker 31B to output a second test sound TS2, and the third speaker 31C to output a third test sound TS3. The frequency bands of the first test sound TS1, the second test sound TS2, and the third test sound TS3 are different, and the first test sound TS1, the second test sound TS2, and the third test sound TS3 are output simultaneously.

[0032] For example, the test sound output control unit 102 controls the simultaneous output of a group of test sounds including the frequency band of the first test sound TS1, the frequency band of the second test sound TS2, and the frequency band of the third test sound TS3 during the execution period of the sound field correction process. This allows the frequency component information used in the frequency analysis process described below to be increased to multiple frequencies compared to the case where only one frequency is used. As a result, the sound field correction process can be performed using a frequency from the multiple frequencies that does not contain noise, thereby improving the calculation accuracy of the impulse response after measurement.

[0033] The receiving unit 103 is exemplified by a function executed by the communication I / F 15. The receiving unit 103 receives an acoustic signal St of a complex sound including a first test sound TS1, a second test sound TS2, and a third test sound TS3. The receiving unit 103 of this embodiment receives the acoustic signal St from the remote control 41 via wireless communication. That is, the receiving unit 103 receives the acoustic signal St of the complex sound acquired by a microphone 45 provided on the remote control 41. Note that the receiving unit 103 may also receive the acoustic signal St via wired communication.

[0034] The recording unit 104 is exemplified by a function executed by the storage 13. The recording unit 104 records the acoustic signal St received by the receiving unit 103 in a predetermined storage device (for example, the storage 13, etc.).

[0035] The calculation unit 105 is, for example, a function executed by the CPU 11. The calculation unit 105 performs a frequency analysis process on the audio signal St recorded by the recording unit 104, analyzing multiple frequency components contained in the audio signal St. Based on the results of the frequency analysis process, the calculation unit 105 calculates the arrival time t1 of the first test sound TS1 from the first speaker 31A to the microphone 45, the arrival time t3 of the second test sound TS2 from the second speaker 31B to the microphone 45, and the arrival time t2 of the third test sound TS3 from the third speaker 31C to the microphone 45, and calculates the time difference between arrival times from each speaker to the microphone 45.

[0036] The calculation unit 105 also performs frequency analysis processing, multiplying the TSP signals acquired from the test sound group by the inverse TSP signals corresponding to the TSP signals. This allows the impulse response of each speaker to be acquired. As a result, the difference in arrival time between the speakers at the microphone 45 can be calculated, thereby reducing the difference in arrival time.

[0037] The memory 12 stores the calculation results of the time difference between the arrival times of the speakers at the listening position calculated by the calculation unit 105. The memory 12 also stores the target amplitude for each speaker, or the ratio of the target amplitudes for the speakers.

[0038] The audio decoder 21 converts the audio data into a digital signal in a format that can be output from the first speaker 31A, the second speaker 31B, and the third speaker 31C, and sends the digital signal to the audio output control unit 101.

[0039] The correction unit 106 is, for example, a function executed by the DSP 23. Based on the time difference between the arrival times of the audio signals from each speaker at the microphone 45 calculated by the calculation unit 105, the correction unit 106 corrects the output timings of the audio signals AS1, AS2, and AS3 output from the first speaker 31A, the second speaker 31B, and the third speaker 31C, respectively. Alternatively, the correction unit 106 corrects the amplitudes of the audio signals AS1, AS2, and AS3 output from the speakers.

[0040] For example, if the arrival time t3 of the second test sound TS2 is later than the arrival time t1 of the first test sound TS1 by Δt1, the correction unit 106 corrects the output timing of the audio AS1 to be delayed by Δt1 from the output timing of the audio AS2. Furthermore, because multiple TSP signals are output from the test sound group, even if there is a TSP signal containing noise, the correction unit 106 can calculate an impulse response from TSP signals using other frequencies and calculate the time it takes for the signal to reach the microphone 45 from the speaker. This improves the accuracy of the output timing correction.

[0041] With the above configuration, the arrival time difference between each of the sounds AS1, AS2, and AS3 due to the positional relationship between the multiple speakers (first speaker 31A, second speaker 31B, and third speaker 31C in this embodiment) and the listening position, or due to communication delays caused by wireless communication, can be calculated from other frequencies even if there is a TSP signal containing noise, because the test sound is in a predetermined frequency band for each speaker.As a result, the time difference can be calculated with high accuracy in a single measurement, and correction can be performed.

[0042] In addition, the amplitude of each speaker is corrected to a target amplitude.

[0043] 3 is a diagram for explaining an example of a method for calculating an impulse response according to an embodiment. As shown in FIG. 3, the horizontal axis represents time t, and the vertical axis represents frequency. An impulse response can be calculated by receiving a TSP (Time Stretched Plus) signal in a certain frequency band output from one speaker and multiplying the received TSP signal by an inverse TSP signal.

[0044] This allows the impulse response to be calculated from multiple frequencies, rather than from a single frequency, so even if some noise is included, the impulse response can be calculated in a single measurement. Figure 3 shows the TSP signal output from one speaker, and the above impulse response calculation is performed for each speaker.

[0045] 4 is a diagram showing an example of a measurement signal according to an embodiment. Specifically, it shows TSP signals of different frequency bands that are received by the receiving unit 103 and output simultaneously from each speaker. As shown in FIG. 4, a composite sound output from the first speaker 31A, the second speaker 31B, and the third speaker 31C is shown. Specifically, FIG. 4(a) shows the composite sound output from multiple speakers, with the vertical axis representing amplitude and the horizontal axis representing time t.

[0046] 4(b), the vertical axis represents frequency and the horizontal axis represents time t, and shows a first output sound m1 from the first speaker 31A, a second output sound w1 from the second speaker 31B, and a third output sound a1 from the third speaker 31C. The first speaker 31A is an example of a main speaker that outputs a high-pitched sound signal. The second speaker 31B is an example of a woofer speaker that outputs a low-pitched or mid-low-pitched sound signal. The third speaker 31C is an example of a top speaker that outputs a high-pitched sound signal.

[0047] The first output sound m1 from the first speaker 31A may be a first test sound TS1. For example, the frequency is a TSP signal of 3 kHz to 5 kHz. The second output sound w1 from the second speaker 31B may be a second test sound TS2. For example, the frequency is a TSP signal of 50 Hz to 300 Hz. The third output sound a1 from the third speaker 31C may be a third test sound TS3. For example, the frequency is a TSP signal of 8 kHz to 6 kHz. An impulse response is calculated by performing frequency analysis on the audio signal received by the receiving unit 103.

[0048] 5A and 5B are diagrams illustrating an example of a TSP signal and an inverse TSP signal of one frequency band according to an embodiment. FIG. 5 illustrates an example of a second output sound w1 from the second speaker 31B. FIG. 5A illustrates a TSP signal of the second output sound w1 from the second speaker 31B. The upper part of FIG. 5A illustrates amplitude on the vertical axis and time t on the horizontal axis, while the lower part of FIG. 5A illustrates frequency on the vertical axis and time t on the horizontal axis.

[0049] Fig. 5(b) shows the inverse TSP signal of the TSP signal of Fig. 5(a). The upper part of Fig. 5(b) shows amplitude on the vertical axis and time t on the horizontal axis, while the lower part of Fig. 5(b) shows frequency on the vertical axis and time t on the horizontal axis. Specifically, it shows the inverse TSP signal of a frequency band corresponding to the second output sound w1 of a certain frequency band output from the second speaker 31B.

[0050] Fig. 6 is a diagram illustrating an example of a calculation result of an impulse response according to an embodiment. Fig. 6 shows an impulse response that can be obtained by multiplying TSP signals, which are recorded output audio signals, by inverse TSP signals of frequency bands corresponding to the TSP signals.

[0051] The upper diagram in FIG. 6 shows an impulse response calculated from the third output sound a1 output from the third speaker 31C. The impulse response of the third output sound a1 indicates that the amplitude reaches a peak value at arrival time t2. The center diagram in FIG. 6 shows an impulse response calculated from the first output sound m1 output from the first speaker 31A. The impulse response of the first output sound m1 indicates that the amplitude reaches a peak value at arrival time t1. The lower diagram in FIG. 6 shows an impulse response calculated from the second output sound w1 output from the second speaker 31B. The impulse response of the second output sound w1 indicates that the amplitude reaches a peak value at arrival time t3.

[0052] As shown in Fig. 6, the difference in arrival time between the speakers at the microphone 45 can be obtained from the calculation results of the impulse responses calculated by the calculation unit 105. Fig. 6 shows that t1 arrives first, followed by t2, and finally by t3. Therefore, in the above example, the first output sound m1 output from the first speaker 31A arrives first, then the third output sound a1 output from the third speaker 31C arrives, and finally the second output sound w1 output from the second speaker 31B arrives.

[0053] The correction unit 106 delays the output timing to match the speaker with the latest arrival time. Therefore, in this case, the output timing of the third output sound a1 output from the third speaker 31C at t2 and the first output sound m1 output from the first speaker 31A at t1 is delayed by control of the delay circuit 25A so as to match the arrival timing of the second output sound w1 output from the second speaker 31B at t3. In this way, the difference in arrival time between the speakers can be reduced by correcting the output timing of the speakers.

[0054] Specifically, the calculation unit 105 calculates the arrival time t1 when the first output sound m1 output from the first speaker 31A reaches the microphone 45, the arrival time t3 when the second output sound w1 output from the second speaker 31B reaches the microphone 45, and the arrival time t2 when the third output sound a1 output from the third speaker 31C reaches the microphone 45. Then, the correction unit 106 corrects the time difference Δt1 between the first output sound m1 of the first speaker 31A and the second output sound w1 of the second speaker 31B by delaying the output timing of the first speaker 31A. Furthermore, the correction unit 106 corrects the time difference Δt2 between the third output sound a1 of the third speaker 31C and the second output sound w1 of the second speaker 31B by delaying the output timing of the third speaker 31C.

[0055] 7 is a flowchart showing an example of processing in the sound field correction device 5 according to the embodiment. As shown in FIG. 7, when the sound field correction processing is started, the test sound output control unit 102 controls the first speaker 31A to output a first test sound TS1 in a first frequency band, the second speaker 31B to output a second test sound TS2 in a second frequency band, and the third speaker 31C to output a third test sound TS3 in a third frequency band. At this time, the first test sound TS1, the second test sound TS2, and the third test sound TS3 are output simultaneously. Note that although test sounds are used in the above example, test sounds or output sound signals may also be used. The first frequency band, the second frequency band, and the third frequency band are different frequency bands that do not overlap with each other (step S1).

[0056] Next, the acoustic signal St of the complex sound including the first test sound TS1, the second test sound TS2, and the third test sound TS3, which is acquired by the microphone 45 placed at the listening position, is received by the receiving unit 103. The recording unit 104 then receives and records the acoustic signal St of the complex sound from the receiving unit 103 (step S2).

[0057] Thereafter, the calculation unit 105 calculates the start position of the measurement signal from the specified frequency of the acoustic signal St recorded in the recording unit 104 (step S3).

[0058] Next, the calculation unit 105 performs frequency analysis by multiplying the start position offset of the audio signal St by the inverse TSPs of different frequency bands. Then, it acquires an impulse response corresponding to the output sound of each speaker. That is, by multiplying the inverse TSP signals corresponding to the TSP signals of each speaker, it acquires an impulse response corresponding to the TSP signals of each speaker (step S4).

[0059] Then, the calculation unit 105 calculates the maximum amplitude position and the amplitude of the impulse response of each test sound (step S5).

[0060] The calculation unit 105 also calculates the time difference between the calculated maximum amplitude positions and the arrival times of the speakers at the listening positions. Furthermore, the calculation unit 105 calculates the magnitude of each amplitude. That is, the calculation unit 105 calculates the amplitude difference based on the target ratio of the amplitude magnitudes of the speakers stored in the memory 12 and the calculated ratio of the amplitude magnitudes of each speaker (step S6).

[0061] Finally, the correction unit 106 controls the delay circuits 25A to 25C based on the calculated time difference between the speakers when they reach the listening position so that the output timing of the sounds from the speakers is synchronized. Also, based on the calculated amplitude difference, the correction unit 106 controls the ratio of the amplitude magnitudes of the speakers to approach a target ratio so that the amplitude of each speaker is optimized (step S7).

[0062] According to the above embodiment, by setting the output signal to a fixed frequency band rather than a single frequency and calculating the impulse response in the frequency band, even if noise is included in some frequencies, the impulse response can be calculated at a frequency within the frequency band that does not include noise. As a result, by setting the frequency band to a fixed frequency band compared to a single frequency, the accuracy with which the impulse response can be calculated in a single measurement can be improved.

[0063] Furthermore, by simultaneously outputting audio signals from each speaker, the maximum amplitude position of the impulse response can be calculated simultaneously. This allows the difference in arrival time from each speaker to the microphone 45 to be corrected with a single measurement. In other words, measurement and correction can be performed in a shorter time than repeated measurements. This allows the sound field correction process to be performed quickly, making it possible to provide a comfortable sound field.

[0064] Other embodiments will be described below, but descriptions of parts that have the same or similar effects as the first embodiment will be omitted as appropriate.

[0065] Next, Fig. 8 is a diagram showing an example of a measurement method according to the second embodiment. Fig. 8 illustrates a method for calculating an impulse response with high accuracy by performing measurements twice when it is difficult for two of three speakers to output TSP signals in different frequency bands, for example.

[0066] FIG. 4 shows measurement signals for three TSP signals. FIG. 8 shows measurement signals for two TSP signals. FIG. 8(a) shows measurement signals obtained by measuring the first output sound m1 output from the first speaker 31A and the second output sound w1 output from the second speaker 31B. FIG. 8(b) shows measurement signals obtained by measuring the second output sound w1 output from the second speaker 31B and the fourth output sound a4 output from the fourth speaker 31D. Note that the fourth speaker 31D may have a different frequency band from the second speaker 31B. Note that in the second embodiment, the third speaker 31C is omitted and the fourth speaker 31D is shown as an example instead, but the third speaker 31C may have a different frequency band from the second speaker 31B.

[0067] As an example, the first output sound m1 output from the first speaker 31A and the fourth output sound a4 output from the fourth speaker 31D are described as being in the same frequency band. Note that the frequency band of the first output sound m1 and the frequency band of the fourth output sound a4 may be different frequency bands, as long as the frequency bands of the speakers being measured simultaneously do not overlap. In other words, the frequency bands of the first speaker 31A and the second speaker 31B do not overlap, and the frequency bands of the fourth speaker 31D and the second speaker 31B do not overlap.

[0068] The upper part of Fig. 8(a) shows amplitude on the vertical axis and time t on the horizontal axis, while the lower part of Fig. 8(a) shows frequency on the vertical axis and time t on the horizontal axis.

[0069] 8(a), a first output sound m1 output from the first speaker 31A and a second output sound w1 output from the second speaker 31B are measured. Here, the frequency band of the first output sound m1 is set to 3 kHz to 5 kHz, and the frequency band of the second output sound w1 is set to 50 Hz to 300 Hz. Then, by multiplying the measured TSP signals by the corresponding inverse TSP signals, the impulse response corresponding to each speaker can be calculated.

[0070] Then, the time difference Δt1 between the speakers is calculated from the maximum amplitude positions of the first speaker 31A and the second speaker 31B calculated from the impulse responses. Furthermore, the amplitude difference is calculated based on the target ratio of the amplitude magnitudes between the speakers and the calculated ratio of the amplitude magnitudes of each speaker.

[0071] Next, Fig. 8(b) similarly shows measurement signals obtained by measuring the second output sound w1 output from the second speaker 31B and the fourth output sound a4 output from the fourth speaker 31D. The upper part of Fig. 8(b) shows amplitude on the vertical axis and time t on the horizontal axis. The lower part of Fig. 8(b) shows frequency on the vertical axis and time t on the horizontal axis.

[0072] 8(b), the frequency band of the second output sound w1 is set to 50 [Hz] to 300 [Hz], and the frequency band of the fourth output sound a4 is set to 3 [kHz] to 5 [kHz]. Then, by multiplying the measured TSP signals by the corresponding inverse TSP signals, the impulse response corresponding to each speaker can be calculated.

[0073] Then, the time difference between the maximum amplitude positions of the second speaker 31B and the fourth speaker 31D calculated from the impulse responses and the time it takes for the speakers to reach the listening position is calculated, and the amplitude difference is calculated based on the target ratio of the amplitude magnitudes of the speakers and the calculated ratio of the amplitude magnitudes of each speaker.

[0074] In other words, the calculation unit 105 calculates the time difference Δt1 between the first output sound m1 in a first frequency band output from the first speaker 31A and the second output sound w1 in a second frequency band different from the first frequency band output from the second speaker 31B, when they reach the listening position; further, after a predetermined time has elapsed, the calculation unit 105 calculates the time difference Δt3 between the second output sound w1 and the fourth output sound a4 in a fourth frequency band different from the second frequency band output from the fourth speaker 31D, when they reach the listening position; and calculates the time difference between the speakers when they reach the listening position based on the time difference Δt1 between the first output sound m1 and the second output sound w1 and the time difference Δt3 between the second output sound w1 and the fourth output sound a4.

[0075] Based on the arrival time difference between the speakers calculated using the calculation results for the first speaker 31A and the second speaker 31B, which are calculated twice, and the calculation results for the second speaker 31B and the fourth speaker 31D, the correction unit 106 controls at least one of the delay circuits 25A to 25C so that the output timing of the sounds from the speakers is synchronized. Also, based on the calculated difference in amplitude between the speakers, control can be performed to bring the ratio of the amplitude magnitudes of the speakers closer to a target ratio so that the amplitude of each speaker is optimized.

[0076] In the second embodiment, low-frequency and high-frequency combinations were used, such as the first speaker 31A and the second speaker 31B, and the second speaker 31B and the fourth speaker 31D. That is, measurements were performed on TSP signals with different frequency bands. This reduces the likelihood of overlap between the frequency bands in each measurement, allowing for more accurate calculation of impulse responses compared to combinations with similar frequency bands.

[0077] In the above embodiment, the explanation has been given taking the example of correction between internal speakers, but at least some of the speakers may be external. In this case, the calculation unit 105 of the sound field correction device 5 calculates the time difference, and correction is performed by a delay circuit provided in the external speaker. Alternatively, correction is performed by a delay circuit configured separately from the external speaker, and the signal is output to the external speaker.

[0078] The number and type of speakers are not limited to those described in the embodiments. For example, correction between two internal speakers or correction between two external speakers can be performed using the same method as described above. Even if there are four or more speakers, the time difference between all speakers can be reduced and the volume balance of each speaker can be optimized by sequentially performing the same processing as in the embodiments.

[0079] The program for realizing the functions of the sound field correction device 5 described above may be provided by being recorded in a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a digital versatile disk (DVD) in the form of a file that can be installed or executed by a computer. Alternatively, the program may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Alternatively, the program may be provided or distributed via a network such as the Internet.

[0080] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0081] 1...acoustic device, 5...sound field correction device, 11...CPU, 12...memory, 13...storage, 14...user I / F, 15...communication I / F, 20...communication bus, 21...audio decoder, 22...audio input ADC, 23...DSP, 25A...first delay circuit, 25B...second delay circuit, 25C...third delay circuit, 31A...first speaker, 31B...second speaker, 31C...third speaker, 31D...fourth speaker, 41...remote Controller, 45...microphone, 46...wireless modulation circuit, 47...transmitter, 101...audio output control section, 102...test sound output control section, 103...receiving section, 104...recording section, 105...calculating section, 106...correcting section, AS1, AS2, AS3...audio, TS1...first test sound, TS2...second test sound, TS3...third test sound, St...acoustic signal, m1...first output sound, w1...second output sound, a1...third output sound, a4...fourth output sound

Claims

1. A sound field correction device that measures sounds output from multiple speakers at a predetermined listening position, an output control unit that controls the plurality of speakers to output sounds having different frequency bands from the plurality of speakers; a receiving unit that receives the outputted voice information; a calculation unit that performs frequency analysis processing for each of the plurality of speakers using the received audio information and calculates a time difference between the times when the audio output from the plurality of speakers reaches a listening position; a correction unit that corrects output timings of the plurality of speakers based on the time difference; A sound field correction device comprising:

2. a memory in which target amplitudes of the plurality of speakers are stored; The calculation unit calculates amplitudes of the sounds from the plurality of speakers. The sound field correction device according to claim 1 .

3. a correction unit that corrects the amplitude of at least one of the speakers based on the calculated amplitude; The sound field correction device according to claim 2 , comprising:

4. The calculation unit calculating a time difference between a first sound in a first frequency band output from a first speaker and a second sound in a second frequency band different from the first frequency band output from a second speaker, the time difference being between the first sound and the second sound reaching the listening position; further calculating a time difference between the second sound and a fourth sound of a fourth frequency band different from the second frequency band output from a fourth speaker, the fourth sound reaching the listening position after a predetermined time has elapsed; calculating a time difference for the sounds output from the plurality of speakers to reach the listening position based on the arrival time difference between the first sound and the second sound and the arrival time difference between the second sound and the fourth sound; The sound field correction device according to claim 1 .

5. A sound field correction method for measuring sounds output from a plurality of speakers at a predetermined listening position, comprising: an output control step of controlling the plurality of speakers so that sounds having different frequency bands are output from the plurality of speakers; receiving information about the outputted voice; a step of performing a frequency analysis process for each of the plurality of speakers using the received audio information, and calculating a time difference between when the audio output from the plurality of speakers reaches the listening position; correcting the output timings of the plurality of speakers based on the time difference; A sound field correction method including:

6. A sound field correction device that measures the sound output from multiple speakers at a specified listening position. a process of controlling the plurality of speakers to output sounds having different frequency bands from the plurality of speakers; A process of receiving information about the outputted voice; a process of performing a frequency analysis process for each of the plurality of speakers using the received audio information, and calculating a time difference between when the audio output from the plurality of speakers reaches the listening position; a process of correcting the output timing of the speaker based on the time difference; A program that executes the following.

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