Sound field correction device, sound field correction method, and program

Abstract

Effectively suppress the influence of the arrival time difference of sound in a plurality of speakers. 【Solution means】The sound field correction device of the embodiment is a sound field correction device that measures the sound output from a plurality of speakers at a predetermined listening position, and controls the output of sounds with different frequency bands for each of the plurality of speakers so as to output from the plurality of speakers. An output control unit, a receiving unit that receives information on the output sound, a calculation unit that performs frequency analysis processing for each of the plurality of speakers using the received sound information, and calculates the time difference for the sound output from the plurality of speakers to reach the listening position, and based on the time difference, And a correction unit that corrects the output timing of the plurality of speakers.

Description

Technical Field

[0001] Embodiments of the present invention relate to a sound field correction device, a sound field correction method, and a program.

Background Art

[0002] In an acoustic device that outputs sound from a plurality of speakers, there may be a sound shift due to the different timings at which the sound output from each speaker reaches the listening position. As a technique for solving such a problem, there is a technique in which a test sound output from a speaker is acquired by a microphone, the time from the speaker to the microphone is measured for each speaker, and a delay time is calculated based on the measured time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above calculation method, it is necessary to measure at each speaker and calculate the delay time. Therefore, the measurement work takes time.

[0005] The problem to be solved by the embodiments 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 the arrival time difference of sound in a plurality of speakers.

Means for Solving the Problems

[0006] The sound field correction device according to the embodiment is a sound field correction device that measures the sound output from a plurality of speakers at a predetermined listening position, and includes an output control unit that controls the output of sounds with different frequency bands for each of the plurality of speakers so as to output the sounds from the plurality of speakers, a reception unit that receives information on the output sound, a calculation unit that performs frequency analysis processing for each of the plurality of speakers using the received sound information and calculates the time difference for the sound output from the plurality of speakers to reach the listening position, and a correction unit that corrects the output timings of the plurality of speakers based on the time difference.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

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

[0009] FIG. 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 voices from a plurality of speakers, and can be, for example, a stereo, a video playback device, a recording device, a television, a home theater system, or the like.

[0010] The audio 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 controller 41.

[0011] The sound field correction device 5 optimizes the output timings of voices AS1, AS2, and AS3 output from the first speaker 31A, the second speaker 31B, and the third speaker 31C respectively according to the positional relationship between the first speaker 31A, the second speaker 31B, the third speaker 31C, and the user's listening position, and executes a sound field correction process for reducing the arrival time difference of the output sounds from the respective speakers. The listening position in this embodiment is assumed to be the position where the remote controller 41 exists.

[0012] The sound field correction device 5 according to 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. These components are connected to be communicable with each other via a communication bus 20.

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

[0014] The audio decoder 21 is a device that converts audio data recorded on a predetermined medium (e.g., CD, DVD, Blu-ray (registered trademark) disk, removable medium, etc.), audio data included in a broadcast wave, 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 signal of audio input from an external device into a digital signal.

[0015] The DSP 23 is a processor that executes predetermined processing on a digital signal corresponding to the sound output from the first speaker 31A, the second speaker 31B, and the third speaker 31C, and generates audio signals of the audio AS1, AS2, AS3 to be listened to, audio signals of the first test sound TS1, the second test sound TS2, and the third test sound TS3 described later, etc.

[0016] The first delay circuit 25A is a circuit that delays the output timing of the audio AS1 output from the first speaker 31A according to 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 according to the 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 according to the correction signal output from the CPU 11.

[0017] The remote controller 41 is a device operable by a user who wants to listen to the audios 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 the acquired sound into an electrical signal (analog signal). The wireless modulation circuit 46 is a circuit that modulates the electrical signal generated by the microphone 45 into a signal (digital signal) in a form capable of wireless communication conforming to a predetermined standard. The transmitter 47 is a device that transmits the signal modulated by the wireless modulation circuit 46 to the sound field correction device 5.

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

[0019] The sound field correction device 5 according to the present embodiment is a sound field correction device 5 that measures the audio output from a plurality of speakers at a predetermined listening position, and includes an output control unit that controls the output of audio with different frequency bands for each of the plurality of speakers so as to output from the plurality of speakers, a receiving unit 103 that receives information on the output audio, an arithmetic unit 105 that performs frequency analysis processing for each of the plurality of speakers using the received audio information and calculates the time difference for the audio output from the plurality of speakers to reach the listening position, and a correction unit 106 that corrects the output timing of the speaker based on the time difference.

[0020] Specifically, when the sound field correction device 5 according to the present embodiment executes the sound field correction process, it 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 bands of the first test sound TS1, the second test sound TS2, and the third test sound TS3 are in different frequency bands, respectively.

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

[0022] The sound field correction device 5 analyzes the frequency components included in the acoustic signal St received from the remote controller 41. That is, it performs a frequency analysis of multiplying the inverse TSP signals corresponding to the respective TSP signals. Then, from the calculated impulse response, the maximum amplitude value of each is obtained, and based on the analysis result, the arrival time t1 from the first speaker 31A of the first test sound TS1 to the microphone 45, the arrival time t3 from the second speaker 31B of the second test sound TS2 to the microphone 45, and the arrival time t2 from the third speaker 31C of the third test sound TS3 to the microphone 45 are calculated, and the time difference for each speaker to reach the microphone 45 is calculated. Also, the magnitude of the amplitude of each speaker is calculated. Specifically, 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 are calculated.

[0023] Then, based on the calculated time difference, the sound field correction device 5 corrects at least one of the output timings of the voice AS1 from the first speaker 31A, the output timing of the voice AS2 from the second speaker 31B, and the output timing of the voice AS3 from the third speaker 31C, that is, executes a delay process for controlling the first delay circuit 25A, the second delay circuit 25B, or the third delay circuit 25C. Also, based on the calculated amplitude difference, the amplitude of at least one speaker is corrected to approach the target amplitude difference. Note that the test sound may also be used as the output voice.

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

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

[0026] The sound field correction device 5 analyzes the frequency components included in the acoustic signal St received from the remote controller 41. That is, frequency analysis is performed by multiplying the inverse TSP signals corresponding to the respective TSP signals. Then, the maximum amplitude value of each is obtained from the calculated impulse response, and based on the analysis result, the time difference Δt1 between the arrival time t1 from the first speaker 31A of the first test sound TS1 to the microphone 45 and the arrival time t3 from the second speaker 31B of the second test sound TS2 to the microphone 45 is calculated. Also, the volume difference between the speakers is calculated from the magnitude of the amplitude.

[0027] Then, based on the calculated time difference Δ1, the sound field correction device 5 performs a process of correcting at least one of the output timings of the voice AS1 from the first speaker 31A and the output timing of the voice AS2 from the second speaker 31B, that is, a process for controlling the first delay circuit 25A or the second delay circuit 25B. Also, based on the calculated amplitude difference, the amplitude of at least one speaker is corrected to approach the target amplitude difference. The test sound may also be used as the output voice.

[0028] FIG. 2 is a block diagram showing an example of the functional configuration of the sound field correction device 5 according to the embodiment. The sound field correction device 5 according to the present embodiment includes a voice output control unit 101, a test sound output control unit 102, a reception unit 103, a recording unit 104, an arithmetic unit 105, a correction unit 106, a memory 12, and a voice decoder 21. These functional units 101 to 106, 12, and 21 can be realized by the cooperation of hardware and software (program) as exemplified in FIG. 1. Also, at least a part of these functional units 101 to 106, 12, and 21 may be realized by dedicated hardware (circuit, etc.).

[0029] The sound field correction device 5 is controlled, for example, by the test sound output control unit 102 of the DSP 23 to output an acoustic signal St from each speaker. Then, the acoustic signal St is received by the reception unit 103 of the communication I / F 15. Next, it is stored in the recording unit 104 of the storage 13. Also, frequency analysis is performed on the TSP signal acquired by the arithmetic unit 105 of the CPU 11. The arithmetic unit 105 calculates the time difference for each speaker to reach the listening position. The correction unit 106 of the DSP 23 corrects the output timing of each speaker by controlling the delay circuits 25A, 25B, and 25C. Then, the voice output control unit 101 of the DSP 23 receives a digital signal from the voice decoder 21 and controls the output of voice from each speaker. The arithmetic unit 105 acquires the target amplitude for each speaker from the memory 12, and the correction unit 106 corrects the amplitude output from each speaker. Note that the correspondence between each functional configuration unit and the hardware configuration unit is an example.

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

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

[0032] The test tone output control unit 102 controls, for example, during the execution period of the sound field correction process, so that a test tone group including the frequency band of the first test tone TS1, the frequency band of the second test tone TS2, and the frequency band of the third test tone TS3 is output simultaneously. Thereby, compared with the case of one frequency, the information of the frequency components used for the frequency analysis process described later can be increased to a plurality of frequencies. As a result, since the sound field correction process can be performed using frequencies that do not include noise from a plurality of frequencies, the calculation accuracy of the impulse response after measurement can be improved.

[0033] The receiving unit 103 is an example of a function executed by, for example, the communication I / F 15. The receiving unit 103 receives the acoustic signal St of the composite sound including the first test tone TS1, the second test tone TS2, and the third test tone TS3. The receiving unit 103 of the present embodiment receives the acoustic signal St from the remote controller 41 via wireless communication. That is, it receives the acoustic signal St of the composite sound acquired by the microphone 45 provided in the remote controller 41. Note that the receiving unit 103 may receive the acoustic signal St via wired communication.

[0034] The recording unit 104 is an example of a function executed by, for example, the storage 13. The recording unit 104 records the acoustic signal St received by the receiving unit 103 in a predetermined storage device (such as the storage 13 or the like).

[0035] The calculation unit 105 is an example of a function executed by, for example, the CPU 11. For the acoustic signal St recorded by the recording unit 104, a frequency analysis process is performed to analyze a plurality of frequency components included in the acoustic signal St. Then, based on the analysis result of the frequency analysis process, the calculation unit 105 calculates the arrival time t1 from the first speaker 31A of the first test sound TS1 to the microphone 45, the arrival time t3 from the second speaker 31B of the second test sound TS2 to the microphone 45, and the arrival time t2 from the third speaker 31C of the third test sound TS3 to the microphone 45, and calculates the time difference for each speaker to reach the microphone 45.

[0036] In addition, the calculation unit 105 performs a frequency analysis process of multiplying the TSP signal acquired from the test sound group by the inverse TSP signal corresponding to the TSP signal. Thereby, the impulse response of each speaker can be obtained. As a result, since the time difference for each speaker to reach the microphone 45 can be calculated, the time difference can be reduced.

[0037] The memory 12 stores the calculation result of the time difference for each speaker to reach the listening position calculated by the calculation unit 105. In addition, it stores the target amplitude for each speaker. Or it stores the ratio of the target amplitudes for each speaker.

[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 it to the audio output control unit 101.

[0039] The correction unit 106 takes, for example, the function executed by the DSP 23 as an example. Based on the time differences from each speaker calculated by the arithmetic unit 105 to reach the microphone 45, the output timings of the voices AS1, AS2, and AS3 output from the first speaker 31A, the second speaker 31B, and the third speaker 31C are corrected. Or, the amplitudes of the voices AS1, AS2, and AS3 output from the speakers are corrected.

[0040] For example, when the arrival time t3 of the second test sound TS2 is Δt1 later than the arrival time t1 of the first test sound TS1, the correction unit 106 performs a correction to delay the output timing of the voice AS1 by Δt1 from the output timing of the voice AS2. Also, since a plurality of TSP signals are output from the test sound group, even when there is a TSP signal containing noise, the correction unit 106 can calculate the impulse response from the TSP signals using other frequencies and calculate the time taken for the sound to reach the microphone 45 from the speaker. Thereby, the correction accuracy of the output timing can be improved.

[0041] With the above configuration, due to the positional relationship between the plurality of speakers (the first speaker 31A, the second speaker 31B, and the third speaker 31C in this embodiment) and the listening position, and the communication delay due to the intervention of wireless communication, etc., the arrival time differences of the respective voices AS1, AS2, and AS3 can be calculated from other frequencies even when 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 accurately calculated and corrected in one measurement.

[0042] Also, the amplitude for each speaker is corrected to be the target amplitude.

[0043] FIG. 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. By receiving a TSP (Time Streched Pluse) signal in a certain frequency band output from one speaker and multiplying the received TSP signal by an inverse TSP signal, the impulse response can be calculated.

[0044] Thus, compared to calculating from one frequency, since it is calculated from a plurality of frequencies, even when some noise is included, the impulse response can be calculated by one measurement. FIG. 3 represents a TSP signal output from one speaker, and the above-mentioned calculation of the impulse response is performed for each speaker.

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

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

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

[0048] FIG. 5 is a diagram showing an example of a TSP signal and an inverse TSP signal in one frequency band according to the embodiment. FIG. 5 shows, as an example, the second output sound w1 of the second speaker 31B. FIG. 5(a) shows the TSP signal of the second output sound w1 of the second speaker 31B. The upper part of FIG. 5(a) represents the vertical axis as amplitude and the horizontal axis as time t, and the lower part of FIG. 5(a) represents the vertical axis as frequency and the horizontal axis as time t.

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

[0050] FIG. 6 is a diagram showing an example of the calculation result of the impulse response according to the embodiment. FIG. 6 shows the impulse response that can be obtained by multiplying the recorded output audio signal, which is a TSP signal, by the inverse TSP signal in the frequency band corresponding to each TSP signal.

[0051] The upper diagram in Fig. 6 represents the 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 the peak value at the arrival time t2. The middle diagram in Fig. 6 represents the 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 the peak value at the arrival time t1. The lower diagram in Fig. 6 represents the 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 the peak value at the arrival time t3.

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

[0053] The correction unit 106 delays in accordance with the speaker with the latest arrival time. Therefore, in this case, the output timings of the third output sound a1 from the third speaker 31C at t2 and the first output sound m1 from the first speaker 31A at t1 are delayed by the 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 which is t3. Thereby, by correcting the output timings of the speakers, the arrival time difference between the speakers can be reduced.

[0054] Specifically, the arithmetic unit 105 calculates the arrival time t1 at which the first output sound m1 output from the first speaker 31A reaches the microphone 45, the arrival time t3 at which the second output sound w1 output from the second speaker 31B reaches the microphone 45, and the arrival time t2 at which 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. Also, 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] FIG. 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 process is started, the test sound output control unit 102 controls the first speaker 31A to output the first test sound TS1 in the first frequency band, controls the second speaker 31B to output the second test sound TS2 in the second frequency band, and controls the third speaker 31C to output the third test sound TS3 in the 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 here, they may also be test voice or output voice signals. The first frequency band, the second frequency band, and the third frequency band are different frequency bands that do not overlap each other (step S1).

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

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

[0058] Next, the arithmetic unit 105 performs a frequency analysis in which inverse TSPs in different frequency bands are multiplied with respect to the start position offset of the acoustic signal St, and obtains an impulse response corresponding to the output sound of each speaker. That is, an impulse response corresponding to the TSP signal of each speaker is obtained by multiplying the inverse TSP signals corresponding to the TSP signals of each speaker (step S4).

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

[0060] Also, the arithmetic unit 105 calculates the time difference from each calculated maximum amplitude position to reach the listening positions between the speakers, and further calculates the magnitude of each amplitude. That is, an amplitude difference is calculated based on the target ratio of the amplitude magnitudes between the speakers stored in the memory 12 and the ratio of the amplitude magnitudes of each calculated speaker (step S6).

[0061] Finally, the correction unit 106 controls the delay circuits 25A to 25C so that the output timings of the voices of the speakers are aligned based on the calculated time difference to reach the listening positions between the speakers. Also, the correction unit 106 performs control to bring the ratio of the amplitude magnitudes of each speaker closer to the target ratio so that the amplitudes of each speaker are optimized based on the calculated amplitude difference (step S7).

[0062] According to the above embodiment, by calculating the impulse response in the frequency band with a constant frequency band instead of one frequency, even when noise is included in some frequencies, the impulse response can be calculated at a frequency that does not include noise within the frequency band. Thereby, by using a constant frequency band as compared with one frequency, the accuracy of calculating the impulse response in one measurement can be improved.

[0063] Also, by simultaneously outputting audio signals from each speaker, the maximum amplitude position of the impulse response can be calculated simultaneously. Therefore, the arrival time difference from each speaker to the microphone 45 can be corrected in one measurement. That is, measurement and correction can be performed in a shorter time compared to repeated measurements. Thus, the sound field correction process can be executed quickly, making it possible to provide a comfortable sound field.

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

[0065] Next, FIG. 8 is a diagram showing an example of a measurement method according to the second embodiment. In FIG. 8, for example, when it is difficult for two of the three speakers to output TSP signals in different frequency bands, a method of accurately calculating the impulse response by measuring in two separate times will be described.

[0066] In FIG. 4, the measurement signals of three TSP signals are shown. In FIG. 8, the measurement signals of two TSP signals are shown respectively. FIG. 8(a) shows the measurement signal 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 the measurement signal 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 only needs to have a different frequency band from the second speaker 31B. In the second embodiment, the third speaker 31C is omitted and the fourth speaker 31D is taken as an example instead, but the third speaker 31C with a different frequency band from the second speaker 31B may also be used.

[0067] As an example, the frequency bands of 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 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 do not overlap between the speakers measured simultaneously. That is, the frequency bands of the first speaker 31A and the second speaker 31B do not need to overlap, and the frequency bands of the fourth speaker 31D and the second speaker 31B do not need to overlap.

[0068] The upper part of FIG. 8(a) shows the vertical axis as amplitude and the horizontal axis as time t. The lower part of FIG. 8(a) shows the vertical axis as frequency and the horizontal axis as time t.

[0069] As shown in FIG. 8(a), the first output sound m1 output from the first speaker 31A and the 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 responses corresponding to each speaker can be calculated.

[0070] Thereafter, 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 response. Furthermore, the difference in amplitude is calculated based on the target ratio of the magnitudes of the amplitudes between the speakers and the ratio of the magnitudes of the amplitudes of each calculated speaker.

[0071] Next, similarly to FIG. 8(b), a measurement signal showing the second output sound w1 output from the second speaker 31B and the fourth output sound a4 output from the fourth speaker 31D is shown. The upper part of FIG. 8(b) shows the vertical axis as amplitude and the horizontal axis as time t. The lower part of FIG. 8(b) shows the vertical axis as frequency and the horizontal axis as time t.

[0072] As shown in Fig. 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 signal by the inverse TSP signal corresponding thereto, the impulse response corresponding to each speaker can be calculated.

[0073] Thereafter, the time difference for reaching the listening positions between the speakers is calculated from the maximum amplitude positions of the second speaker 31B and the fourth speaker 31D calculated from the impulse response. Further, the difference in amplitude is calculated based on the target ratio of the magnitudes of the amplitudes between the speakers and the ratio of the magnitudes of the amplitudes of the calculated respective speakers.

[0074] In other words, the arithmetic unit 105 calculates the time difference Δt1 for reaching the listening position between the first output sound m1 in the first frequency band output from the first speaker 31A and the second output sound w1 in the second frequency band different from the first frequency band output from the second speaker 31B. Further, after a predetermined time has elapsed, the time difference Δt3 for reaching the listening position between the second output sound w1 and the fourth output sound a4 in the fourth frequency band different from the second frequency band output from the fourth speaker 31D is calculated, and based on the time difference Δt1 for reaching the first output sound m1 and the second output sound w1 and the time difference Δt3 for reaching the second output sound w1 and the fourth output sound a4, the time difference for reaching the listening positions between the speakers is calculated.

[0075] Based on the time difference for reaching the speakers calculated using the calculation results between the first speaker 31A and the second speaker 31B calculated in two parts and the calculation results between the second speaker 31B and the fourth speaker 31D, at least one of the delay circuits 25A to 25C is controlled by the correction unit 106 so that the output timings of the voices of the respective speakers are synchronized. Also, based on the calculated difference in amplitude between the speakers, control can be performed to bring the ratio of the magnitudes of the amplitudes of the respective speakers closer to the target ratio so that the amplitudes of the respective speakers are optimized.

[0076] Also, in the second embodiment, combinations of a low frequency range and a high frequency range are used, such as between the first speaker 31A and the second speaker 31B, and between the second speaker 31B and the fourth speaker 31D. That is, measurements of TSP signals with separated frequency bands are respectively performed. As a result, since the bands are less likely to overlap in each measurement, the impulse response can be calculated with higher accuracy compared to combinations with closer frequency bands.

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

[0078] Also, the number and types of speakers are not limited to the embodiment. For example, correction between two internal speakers or correction between two external speakers can also be performed by the same method as above. Further, even when there are four or more speakers, by sequentially executing the same processing as in the embodiment, the time difference between all speakers can be reduced and the volume balance of each speaker can be optimized.

[0079] A program for realizing the functions of the sound field correction device 5 as described above may be provided by being recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk) in a file in a form installable on a computer or an executable form. Further, the program may be configured to be stored on a computer connected to a network such as the Internet and downloaded via the network for providing. Further, the program may be configured to 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 implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[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 control, 45... Microphone, 46... Wireless modulation circuit, 47... Transmitter, 101... Audio output control unit, 102... Test tone output control unit, 103... Receiver, 104... Recording unit, 105... Arithmetic unit, 106... Correction unit, AS1, AS2, AS3... Audio, TS1... First test tone, TS2... Second test tone, TS3... Third test tone, St... Acoustic signal, m1... First output sound, w1... Second output sound, a1... Third output sound, a4... Fourth output sound

Claims

1. An acoustic field correction device that measures the sound output from a plurality of speakers at a predetermined listening position, comprising: an output control unit that controls the output of the sound of the TSP signal having different frequency bands for each of the plurality of speakers so as to output from the plurality of speakers; a receiving unit that receives the information of the output sound; a memory that stores the target amplitude of the plurality of speakers; a calculation unit that performs frequency analysis processing for each of the plurality of speakers using the received sound information, calculates the time difference for the sound output from the plurality of speakers to reach the listening position, and calculates the amplitude of the sound of the plurality of speakers; a correction unit that corrects the output timing of the plurality of speakers based on the time difference, and corrects the amplitude of the speakers based on the calculated amplitude; An acoustic field correction device comprising:

2. The calculation unit: calculates the time difference for the first sound in the first frequency band output from the first speaker and the second sound in the second frequency band different from the first frequency band output from the second speaker to reach the listening position; further calculates, after a predetermined time has elapsed, the time difference for the second sound and the fourth sound in the fourth frequency band different from the second frequency band output from the fourth speaker to reach the listening position; calculates the time difference for the sound 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 acoustic field correction device according to claim 1.

3. An acoustic field correction method for measuring the sound output from a plurality of speakers at a predetermined listening position, comprising: an output control step of controlling the output of the sound of the TSP signal having different frequency bands for each of the plurality of speakers so as to output from the plurality of speakers; a step of receiving the information of the output sound; a step of performing frequency analysis processing for each of the plurality of speakers using the received sound information, calculating the time difference for the sound output from the plurality of speakers to reach the listening position, and calculating the amplitude of the sound of the plurality of speakers; a step of correcting the output timing of the plurality of speakers based on the time difference, and correcting the amplitude of the speakers to the target amplitude of the plurality of speakers based on the calculated amplitude; An acoustic field correction method including:

4. An acoustic field correction device that measures the sound output from a plurality of speakers at a predetermined listening position, a process of controlling the output of the sound of a TSP signal with a different frequency band for each of the plurality of speakers from the plurality of speakers; a process of receiving the information of the output sound; a process of performing frequency analysis processing for each of the plurality of speakers using the received sound information, calculating the time difference for the sound output from the plurality of speakers to reach the listening position, and calculating the amplitude of the sound of the plurality of speakers; a process of correcting the output timing of the speaker based on the time difference and correcting the amplitude of the speaker to the target amplitude of the plurality of speakers based on the calculated amplitude; A program to execute.

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