JP7319789B2 - PHASE CONTROL DEVICE, AUDIO DEVICE, AND PHASE CONTROL METHOD - Google Patents

Description

The present invention relates to a phase control device, acoustic device and phase control method.

In general, speakers are installed at a plurality of positions in a vehicle compartment. For example, the right front speaker for the right door (driver's side door) and the left front speaker for the left door (passenger side door) are installed in symmetrical positions with respect to the center line of the cabin space. there is However, these speakers are not positioned symmetrically with respect to the listener's listening position (driver's seat, passenger's seat, rear seat, etc.).

For example, when the listener sits in the driver's seat, the distance between the right front speaker and the listener is not equal to the distance between the left front speaker and the listener. For right-hand drive vehicles, the former distance is shorter than the latter distance. Therefore, when sound is output from both door speakers at the same time, the listener sitting in the driver's seat hears the sound output from the right front speaker, and then the sound output from the left front speaker. is common. Differences in distance between the listening position of the listener and each of the plurality of speakers (differences in arrival times of reproduced sounds emitted from each speaker) cause bias in sound image localization due to the Haas effect.

As an example of technology for improving the bias of sound image localization, time alignment is known, which sets a delay time for each speaker channel so that the sounds output from each speaker reach the listener (listening position) at the same time. A specific configuration of an apparatus for performing time alignment is described in Patent Document 1, for example.

In order to set the delay time for each speaker channel, the device described in Patent Document 1 sequentially picks up sounds sequentially output from each speaker at a predetermined listening position, and generates an impulse for each speaker from each picked-up sound. Measure the response. In Patent Document 1, a low-pass filter is applied to the impulse response to remove high-frequency noise, thereby detecting the rising portion of the impulse response with high accuracy, thereby improving the calculation accuracy of the delay time to be set for each speaker channel. ing.

JP 2005-341534 A

In a special listening environment such as a vehicle interior, interference between sounds output from each speaker is likely to occur. Therefore, with conventional techniques such as time alignment for localizing a sound image, dips occur in the frequency domain due to such interference, and it is difficult to avoid deterioration of sound quality and reduction in sound pressure due to the occurrence of dips.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to improve the bias of sound image localization and to suppress sound quality deterioration and sound pressure reduction due to interference between sounds output from each speaker. To provide a phase control device, an acoustic device, and a phase control method capable of

A phase control device according to an embodiment of the present invention measures the impulse response of each sound signal output from each of a plurality of speakers and picked up at a predetermined listening position at non-interfering timing. a Fourier transform unit for obtaining a frequency spectrum signal of the impulse response for each speaker by Fourier transforming the impulse response of the measured sound signal from each speaker; On the other hand, a first amplitude characteristic is obtained by performing predetermined phase control and synthesizing with another frequency spectrum signal not subjected to predetermined phase control, and synthesizing with another frequency spectrum signal without performing phase control. and an amplitude characteristic calculator that obtains a second amplitude characteristic by detecting a speaker that satisfies a predetermined condition from among a plurality of speakers based on the first amplitude characteristic and the second amplitude characteristic obtained for each speaker. At a plurality of listening positions including a predetermined listening position, a plurality of Second phase adjustment data for adjusting the phase of the sound signal output to each of the plurality of speakers for each frequency spectrum so that the destructive effect due to sound interference between the speakers is reduced in each frequency spectrum and a generation unit that generates the

According to the phase control device configured in this way, it is possible to improve the bias in localization of the sound image and suppress deterioration in sound quality and reduction in sound pressure due to interference between sounds output from the respective speakers.

The detection unit calculates a level difference between the first amplitude characteristic and the second amplitude characteristic for each speaker, compares values corresponding to the level difference calculated for each speaker, and determines a predetermined level based on the comparison result. A configuration may be adopted in which a speaker that satisfies the condition is detected. More specifically, the detection unit calculates the level difference for each frequency spectrum, accumulates the calculated level difference for each frequency spectrum, compares the accumulated level difference values obtained for each speaker, and determines that the accumulated value is A configuration may be adopted in which the loudest speaker is detected as the speaker that satisfies a predetermined condition.

By generating the second phase adjustment data based on the first phase adjustment data for adjusting the phase of the sound signal output to the speaker detected in this way for each frequency spectrum, In addition to improving the localization of the sound image, it is possible to suppress deterioration in sound quality and reduction in sound pressure due to interference between sounds output from each speaker.

The amplitude characteristic calculator may be configured to perform the following processes (1) to (5) for each frequency spectrum signal obtained by the Fourier transform.
(1) changing the phase of the frequency spectrum signal to be processed, and synthesizing the frequency spectrum signal to be processed with another frequency spectrum signal each time the phase is changed;
(2) Based on the synthesis result, obtain the phase adjustment amount of the sound signal from the speaker to be processed for each frequency spectrum,
(3) Complex multiplication of the obtained phase adjustment amount for each frequency spectrum and the frequency spectrum signal to be processed,
(4) obtaining a first amplitude characteristic by combining the complex-multiplied frequency spectrum signal with another frequency spectrum signal;
(5) A second amplitude characteristic is obtained by synthesizing the frequency spectrum signal to be processed and another frequency spectrum signal without changing the phase.

By using the first amplitude characteristic and the second amplitude characteristic thus obtained, an effect (the effect of increasing the level by reducing destructive interference of sound between speakers at the listening position) can be obtained. Therefore, a more suitable speaker can be detected.

The first phase adjustment data is, for example, whether the phase of the sound output from the speaker detected by the detection unit and the phase of the sound output from the other speaker are in phase or opposite in each frequency spectrum at the listening position. This is data for adjusting the phase of the detected sound output to the speaker for each frequency spectrum.

By using such first phase adjustment data, the bias of sound image localization is improved, and the second phase adjustment data, which is more suitable for suppressing sound quality deterioration and sound pressure drop due to interference between sounds output from each speaker, is used. of phase adjustment data can be generated.

The generation unit calculates, for each frequency spectrum, a phase adjustment amount to be applied to the sound signal output to each of the plurality of speakers based on the first phase adjustment data, and performs phase adjustment for each calculated frequency spectrum. A configuration may be adopted in which the amount is obtained as the second phase adjustment data. In this case, the generation unit may calculate the phase adjustment amount such that the difference in the phase adjustment amount given to the sound signal output to each of the plurality of speakers is within 180 degrees for each frequency spectrum.

This makes it possible, under a given listening environment (e.g., at both a listening position that is asymmetric with respect to the position of the pair of speakers and another listening position that is also asymmetric with respect to the position of the pair of speakers), to achieve even greater , sound interference between speakers due to reversed phase can be reduced, localization can be improved, and deterioration of sound quality and reduction in sound pressure due to occurrence of dips can be suppressed.

An acoustic device according to an embodiment of the present invention is a device that includes the phase control device described above, outputs sound signals input from a sound source to a plurality of speakers, and uses second phase adjustment data to Alternatively, an adjustment unit may be provided for adjusting the phase of the sound signal input from the sound source and output to each of the plurality of speakers for each frequency spectrum.

According to the acoustic device configured in this way, it is possible to improve the bias of sound image localization at the listening position and to output to each speaker a sound signal that suppresses sound quality deterioration and sound pressure reduction due to interference between sounds at the listening position. becomes possible.

A phase control method executed by a computer according to an embodiment of the present invention is a phase control method for each sound signal output from each of a plurality of speakers and collected at a predetermined listening position at non-interfering timing. a measuring step of measuring an impulse response; a Fourier transforming step of obtaining a frequency spectrum signal of the impulse response for each speaker by Fourier transforming the impulse response of the measured sound signal from each speaker; Predetermined phase control is performed on each of the obtained frequency spectrum signals, and a first amplitude characteristic is obtained by synthesizing with other frequency spectrum signals that are not subjected to predetermined phase control, and the other frequency spectrum signals are obtained without performing phase control. Amplitude characteristic calculation step for obtaining a second amplitude characteristic by synthesizing with the frequency spectrum signal of, and a predetermined amplitude characteristic among a plurality of speakers based on the first amplitude characteristic and the second amplitude characteristic obtained for each speaker including a predetermined listening position based on a detection step of detecting a speaker that satisfies a condition and first phase adjustment data for adjusting the phase of a sound signal output to the detected speaker for each frequency spectrum; For adjusting the phase of the sound signal output to each of the plurality of speakers for each frequency spectrum so that the attenuation due to sound interference between the plurality of speakers is reduced in each frequency spectrum at a plurality of listening positions. and a generating step of generating second phase adjustment data.

According to such a phase control method, it is possible to improve the imbalance of sound image localization and to suppress deterioration in sound quality and reduction in sound pressure due to interference between sounds output from each speaker.

INDUSTRIAL APPLICABILITY According to an embodiment of the present invention, a phase control device, an acoustic device, and a phase control capable of improving the bias of sound image localization and suppressing deterioration in sound quality and reduction in sound pressure due to interference between sounds output from each speaker. A method is provided.

1 is a diagram schematically showing a vehicle in which an acoustic system according to an embodiment of the invention is installed; FIG. 1 is a block diagram showing the configuration of an acoustic system according to one embodiment of the present invention; FIG. FIG. 5 is a diagram showing a flowchart of phase adjustment data setting processing executed in the acoustic system according to one embodiment of the present invention; FIG. 2 is a block diagram showing the configuration of a calculation unit included in the acoustic device provided in the acoustic system according to one embodiment of the present invention; FIG. 5(a) is a diagram showing the impulse response between the left front speaker and the listening position (driver's seat), and FIG. 5(b) is a diagram showing the impulse response between the right front speaker and the listening position. FIG. 6A is a diagram showing amplitude characteristics for each frequency spectrum obtained by Fourier transforming the impulse response between the left front speaker and the listening position, and FIG. FIG. 10 is a diagram showing amplitude characteristics for each frequency spectrum obtained by Fourier transforming an impulse response between; FIG. 7A is a diagram showing phase characteristics for each frequency spectrum obtained by Fourier transforming the impulse response between the left front speaker and the listening position, and FIG. FIG. 10 is a diagram showing phase characteristics for each frequency spectrum obtained by Fourier transforming an impulse response between; FIG. 8(a) is a diagram showing the result of synthesis when the frequency spectrum signal obtained by Fourier transforming the impulse response between the left front speaker and the listening position is processed. FIG. 10 is a diagram showing a synthesis result when processing a frequency spectrum signal obtained by Fourier transforming an impulse response between the right front speaker and the listening position; FIG. 9A shows Fourier transform of the impulse response between the left front speaker and the listening position when the phase of the sound from the right front speaker and the phase of the sound from the left front speaker are in phase at the listening position. FIG. 9B is a diagram showing the phase adjustment amount of the frequency spectrum signal obtained by FIG. 9B when the phase of the sound from the right front speaker and the phase of the sound from the left front speaker are in phase at the listening position. , and the phase adjustment amount of the frequency spectrum signal obtained by Fourier transforming the impulse response between the right front speaker and the listening position. FIG. 10(a) is a diagram showing the first amplitude characteristic and the second amplitude characteristic obtained for the frequency spectrum signal obtained by Fourier transforming the impulse response between the left front speaker and the listening position. 10(b) is a diagram showing the first amplitude characteristic and the second amplitude characteristic obtained for the frequency spectrum signal obtained by Fourier transforming the impulse response between the right front speaker and the listening position. FIG. 11(a) is a diagram showing the level difference between the first amplitude characteristic and the second amplitude characteristic shown in FIG. 10(a) for each frequency spectrum, and FIG. It is a figure which shows the level difference of the 1st amplitude characteristic and 2nd amplitude characteristic shown to b) for every frequency spectrum. The frequency spectrum signal obtained by Fourier transforming the impulse response between the right front speaker and the listening position when the phase of the sound from the right front speaker and the phase of the sound from the left front speaker are opposite at the listening position. is a diagram showing a phase adjustment amount (first phase adjustment data) for each frequency spectrum of . FIG. 4 is a diagram showing a phase adjustment amount for each frequency spectrum determined in step S23 of FIG. 3; FIG. FIG. 5 is a diagram showing a phase adjustment amount (first phase adjustment data for a reference speaker) after smoothing processing by a smoothing processing unit included in a calculation unit according to an embodiment of the present invention; FIG. 5 is a diagram showing a phase adjustment amount (second phase adjustment data for another speaker) obtained by a phase inverter included in the audio device according to the embodiment of the present invention; 3 is a block diagram showing the configuration of a phase adjustment unit included in the audio device according to one embodiment of the present invention; FIG. FIG. 17(a) is a diagram showing the time characteristics of an audio signal picked up by a microphone installed in the driver's seat in an example without control, and FIG. FIG. 4 is a diagram showing time characteristics of an audio signal picked up by an installed microphone; FIG. 18(a) is a diagram showing the time characteristics of an audio signal picked up by a microphone installed in the front passenger seat in an example without control, and FIG. FIG. 4 is a diagram showing time characteristics of an audio signal picked up by an installed microphone; FIG. 10 is a diagram showing the frequency characteristics of an audio signal with no control and the frequency characteristics of an audio signal with a phase adjustment, which are picked up by a microphone installed in the driver's seat; FIG. 10 is a diagram showing the frequency characteristics of an audio signal with no control and the frequency characteristics of an audio signal with phase adjustment, which are picked up by a microphone installed in the front passenger's seat; In another embodiment, it is a figure which shows the frequency characteristic of the audio signal of the example of no control, and the frequency characteristic of the audio signal of the example of phase adjustment which are picked up with the microphone installed in the driver's seat. FIG. 10 is a diagram showing the frequency characteristics of an audio signal without control and the frequency characteristics of an audio signal with phase adjustment, picked up by a microphone installed in the front passenger seat, in another embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, an acoustic system will be described as an example of an embodiment of the present invention.

FIG. 1 is a diagram schematically showing a vehicle A in which an acoustic system 1 according to one embodiment of the invention is installed. FIG. 2 is a block diagram showing the configuration of this acoustic system 1. As shown in FIG.

As shown in FIGS. 1 and 2, the audio system 1 includes an audio device 10, speakers SP _FR , SP _FL , and a microphone MIC.

The acoustic device 10 improves the bias of sound image localization that tends to occur in a listening environment such as a vehicle interior, and suppresses deterioration in sound quality and reduction in sound pressure due to interference between sounds output from the speakers installed in the vehicle A. A phase adjustment data generation function (in other words, a phase control device) for generating phase adjustment data is installed.

Various processes in the audio device 10 are executed by cooperation between software and hardware provided in the audio device 10 . At least an OS (Operating System) portion of the software provided in the acoustic device 10 is provided as an embedded system, but other portions, such as a software module for executing phase adjustment data generation processing, , may be provided as an application that can be distributed on a network or held in a recording medium such as a memory card. That is, the phase adjustment data generation function according to the present embodiment may be a function that is preinstalled in the audio device 10 or a function that can be added to the audio device 10 via a network or via a recording medium.

As shown in FIG. 1, the speaker SP _FR is a right front speaker embedded in the right door (driver side door), and the speaker SP _FL is embedded in the left door (passenger side door). is the left front speaker. The vehicle A may further have another speaker (for example, a rear speaker) installed (that is, three or more speakers installed).

The acoustic device 10 has a control section 100 , a display section 102 , an operation section 104 , a measurement signal generation section 106 , a recording medium reproduction section 108 , a phase adjustment section 110 , an amplification section 112 , a signal recording section 114 and a calculation section 116 .

FIG. 3 is a diagram showing a flowchart of the phase adjustment data setting process executed in the acoustic system 1. As shown in FIG. Various processes in the acoustic system 1 including the phase adjustment data setting process shown in this flowchart are executed under the control of the control unit 100 . When receiving a predetermined touch operation on the display unit 102 or a predetermined operation on the operation unit 104, the control unit 100 starts executing the phase adjustment data setting process shown in this flowchart.

When the phase adjustment data setting process shown in FIG. 3 is started, the measurement signal generator 106 generates a predetermined measurement signal (step S11). The generated measurement signal is, for example, an M-sequence code (maximal length sequence). The length of this measurement signal should be at least twice the code length. Note that the measurement signal may be another type of signal such as a TSP signal (Time Stretched Pulse).

The measurement signal is output through the control section 100 and the phase adjustment section 110, and is sequentially output to the speakers SP _FR and SP _FL via the amplification section 112 (step S12). As a result, predetermined measurement sounds are sequentially output from the speakers SP _FR and SP _FL at predetermined time intervals.

In this embodiment, the driver's seat is used as the impulse response measurement position (listening position). Therefore, the microphone MIC is installed in the driver's seat. The installation position of the microphone MIC changes according to the listening position. The microphone MIC may be installed in the passenger seat or the rear seat.

The microphone MIC picks up the measurement sounds sequentially output from the speakers SP _FR and SP _FL at non-interfering timings. A measurement sound signal (that is, a measurement signal) picked up by the microphone MIC is input to the calculation section 116 via the signal recording section 114 (step S13).

FIG. 4 is a block diagram showing the configuration of the calculation unit 116. As shown in FIG. As shown in FIG. 4, calculation unit 116 has measurement units 116A and 116B.

The measurement units 116A and 116B measure impulse responses (step S14).

Specifically, the measurement unit 116A calculates the cross-correlation function between the measurement signal of the measurement sound from the speaker SP _FL (hereinafter referred to as "measurement signal L") and the reference measurement signal, The impulse response of the signal L (in other words, the impulse response between the loudspeaker SP _FL and the listening position, hereinafter referred to as "impulse response L'") is calculated.

The measurement unit 116B calculates the cross-correlation function between the measurement signal of the measurement sound from the speaker SP _FR (hereinafter referred to as "measurement signal R") and the reference measurement signal, and calculates the impulse response of the measurement signal R. (In other words, the impulse response between the speaker SP _FR and the listening position, hereinafter referred to as "impulse response R'") is calculated.

The reference measurement signal is the same as the measurement signal generated by the measurement signal generator 106, and is time-synchronized.

In this way, the measurement units 116A and 116B are measurement units that measure the impulse response of each sound signal output from each of a plurality of speakers and picked up at a predetermined listening position at non-interfering timing. Operate.

FIG. 5(a) illustrates an impulse response L', and FIG. 5(b) illustrates an impulse response R'. 5A and 5B, the vertical axis indicates amplitude and the horizontal axis indicates time (unit: sec). In the examples of FIGS. 5A and 5B, the sampling frequency is 44.1 kHz, the code length of the M-sequence code is 32,767, and the frequency band is 3 kHz.

5(a) and 5(b), it can be seen that the vehicle interior is a special listening environment (there are many reflections with a short delay time difference due to the structures inside the vehicle, sound is shielded by the structures inside the vehicle, and so on). environment), the suppressed sound reaches the listening position first (in other words, the level of the rising part of the impulse response is low) and lags behind this suppressed sound. , a high-level sound reaches the listening position.

As shown in FIG. 4, calculator 116 includes Fourier transform units 116C and 116D.

The Fourier transform unit 116C Fourier transforms the impulse response L' input from the measurement unit 116A, and obtains amplitude characteristics and phase characteristics for each frequency spectrum (step S15). The Fourier transform unit 116D Fourier transforms the impulse response R' input from the measurement unit 116B, and obtains amplitude characteristics and phase characteristics for each frequency spectrum (step S15).

FIG. 6(a) is a diagram showing the amplitude characteristic for each frequency spectrum obtained by Fourier transforming the impulse response L′, and FIG. 6(b) is a diagram showing the amplitude characteristic obtained by Fourier transforming the impulse response R′. FIG. 4 is a diagram showing amplitude characteristics for each frequency spectrum; 6A and 6B, the vertical axis indicates power (unit: dB) and the horizontal axis indicates frequency (unit: Hz).

FIG. 7(a) is a diagram showing the phase characteristics for each frequency spectrum obtained by Fourier transforming the impulse response L′, and FIG. 7(b) is a diagram showing the phase characteristics obtained by Fourier transforming the impulse response R′. FIG. 4 is a diagram showing phase characteristics for each frequency spectrum; 7A and 7B, the vertical axis indicates angle (unit: degree) and the horizontal axis indicates frequency (unit: Hz).

In the examples of FIGS. 6(a), 6(b), 7(a) and 7(b), the Fourier transform length is 8,192 samples. Also, the frequency spectrum is set to 4,097 points obtained by dividing the frequency region from 0 Hz to 22.05 kHz of the Nyquist frequency in increments of 5.38 Hz. Note that the frequency spectrum up to 3 kHz has 557 points. Since the sound is reflected, shielded, interfered, etc. in the vehicle interior, in the examples of FIGS. 6A and 6B, the amplitude fluctuates greatly for each frequency, In the example of , the phase fluctuates greatly for each frequency.

Hereinafter, for convenience, the amplitude characteristics and phase characteristics for each frequency spectrum of the impulse response L′ obtained by the Fourier transform unit 116C are referred to as “frequency spectrum signal L″”, and the impulse response R′ obtained by the Fourier transform unit 116D is The amplitude characteristics and phase characteristics for each frequency spectrum are referred to as "frequency spectrum signal R"". The Fourier transform units 116C and 116D operate as Fourier transform units that obtain impulse response frequency spectrum signals for each speaker by Fourier transforming the impulse response of the sound signal from each speaker.

As shown in FIG. 4, the calculator 116 has a phase controller 116E.

The phase control unit 116E performs the following processes (1) to (5) in order to obtain a first amplitude characteristic and a second amplitude characteristic (both of which will be described later in detail) for each of the frequency spectrum signals L″ and R″. conduct.

<<Processing (1)>>
The phase control unit 116E changes the phase of the frequency spectrum signal to be processed (one of the frequency spectrum signal L″ and the frequency spectrum signal R″) in a range of −180 degrees to +180 degrees in predetermined angular increments. Then, the frequency spectrum signal to be processed and another frequency spectrum signal (the other of frequency spectrum signal L″ and frequency spectrum signal R″) are synthesized (step S16). In order to reduce the processing load, this synthesizing process is performed not for all frequency spectrums but for each frequency spectrum of 557 points up to 3 kHz, for example.

FIG. 8(a) is a diagram showing the synthesis result when the frequency spectrum signal L″ is processed, and FIG. 8(b) shows the synthesis result when the frequency spectrum signal R″ is processed. It is a diagram. FIGS. 8A and 8B show, as representatives, results of synthesizing frequency spectra at 100 Hz (thick solid line) and 400 Hz (thin solid line) out of the 557-point frequency spectrum. 8(a) and 8(b), the vertical axis indicates the power (unit: dB) of the combined signal, and the horizontal axis indicates the phase (unit: degree). Note that the power at a phase of 0 degrees (in other words, the phase adjustment amount is zero) indicates the power when the frequency spectrum signal to be processed is synthesized with another frequency spectrum signal without changing the phase.

<<Processing (2)>>
8(a) and 8(b), at the angle at which the power is maximized, the phase of the sound from the speaker SP _FR and the phase of the sound from the speaker SP _FL are in phase at the listening position (listening position At the angle where the power is minimized, the phase of the sound from the speaker SP _FR and the phase of the sound from the speaker SP _FL are in opposite phase at the listening position. (At the listening position, the sound between these speakers causes the most destructive interference).

In the example of FIG. 8(a), in the frequency spectrum of 100 Hz, when combining the frequency spectrum signal R″ with no phase adjustment and the frequency spectrum signal L″ with the phase adjustment amount of −110° at −110° ) and out-of-phase at +70 degrees (when the frequency spectrum signal R″ that is not phase-adjusted and the frequency spectrum signal L″ with the phase adjustment amount of +70 degrees are combined). In the frequency spectrum of 400 Hz, at +170 degrees (when the frequency spectrum signal R″ not phase-adjusted and the frequency spectrum signal L″ with phase adjustment of +170 degrees are combined), they are in phase, and at −10 degrees ( When the frequency spectrum signal R″ which is not phase-adjusted and the frequency spectrum signal L″ whose phase adjustment amount is -10 degrees are synthesized, the phases are reversed.

In the example of FIG. 8(b), in the frequency spectrum of 100 Hz, at +110 degrees (when the frequency spectrum signal L″ without phase adjustment and the frequency spectrum signal R″ with the phase adjustment amount of +110 degrees are synthesized) At -70 degrees (when the frequency spectrum signal L'' which is not phase-adjusted and the frequency spectrum signal R'' which is phase-adjusted at -70 degrees are combined), they are in phase. In the frequency spectrum of 400 Hz, it is in-phase at -170 degrees (when the frequency spectrum signal L'' which is not phase-adjusted and the frequency spectrum signal R'' whose phase is adjusted by -170 degrees are combined), and at +10 degrees (phase When the unadjusted frequency spectrum signal L'' and the frequency spectrum signal R'' with a phase adjustment of +10 degrees are combined, they are in phase opposition.

The phase control unit 116E determines the frequency of the frequency spectrum signal to be processed when the phase of the sound from the speaker SP _FR and the phase of the sound from the speaker SP _FL are in phase at the listening position, based on the synthesis result for each frequency spectrum. A phase adjustment amount for each spectrum is obtained (step S17).

FIG. 9(a) shows the frequency spectrum signal L″ when the phase of the sound from the speaker SP _FR and the phase of the sound from the speaker SP _FL are in phase at the listening position in each frequency spectrum from 60 Hz to 3 kHz. 9(b) shows the phase adjustment amount for each frequency spectrum of 60 Hz to 3 kHz, in which the phase of the sound from the speaker SP _FR and the phase of the sound from the speaker SP _FL FIG. 4 is a diagram showing the amount of phase adjustment for each frequency spectrum of the frequency spectrum signal R″ when they are in-phase at the listening position; 9(a) and 9(b), the vertical axis indicates the phase adjustment amount (unit: degree), and the horizontal axis indicates the frequency (unit: Hz).

The frequency range for phase adjustment can be arbitrarily set within the range of the Nyquist frequency. In this embodiment, from the lower limit frequency (60 Hz) that can be reproduced by the speakers SP _FR and SP _FL , the frequency at which the phase is dominant in terms of hearing in localization (in other words, the frequency at which the phase shift has a large effect on sound image localization) ) is set as the frequency range for phase adjustment.

In this embodiment, the phase adjustment amount varies greatly for each frequency due to the difference in propagation delay time for each frequency in the vehicle interior (see FIGS. 9A and 9B).

<<Processing (3)>>
The phase control unit 116E converts the frequency spectrum signal to be processed (the frequency spectrum signal L″ itself or the frequency spectrum signal R″ itself) into a complex number, and the phase adjustment amount for each frequency spectrum to be processed obtained in step S17. (see FIG. 9(a) or 9(b)) are converted into complex numbers, and these are complex-multiplied (step S18).

<<Processing (4)>>
The phase control unit 116E performs the complex multiplication (in other words, phase-controlled) frequency spectrum signal to be processed in step S18 and another frequency spectrum signal (frequency spectrum signal L" itself or frequency spectrum signal R" itself). are combined to obtain the first amplitude characteristic (step S19).

<<Processing (5)>>
The phase control unit 116E converts the frequency spectrum signal to be processed into another frequency spectrum signal (the frequency spectrum signal L'' itself or the frequency spectrum signal R'' itself) without changing the phase A second amplitude characteristic is obtained by synthesizing with the frequency spectrum signal R'' itself) (step S20).

Through the above processes (1) to (5), the first amplitude characteristic and the second amplitude characteristic are obtained for each of the frequency spectrum signals L'' and R''. In this way, phase control section 116E performs predetermined phase control on each frequency spectrum signal obtained by the Fourier transform section, and synthesizes the frequency spectrum signal with other frequency spectrum signals that are not subjected to predetermined phase control. It operates as an amplitude characteristic calculator that obtains one amplitude characteristic and obtains a second amplitude characteristic by synthesizing with another frequency spectrum signal without performing phase control.

FIG. 10(a) shows a first amplitude characteristic (solid line) and a second amplitude characteristic (broken line) obtained for the frequency spectrum signal L″, and FIG. 10(b) shows the frequency spectrum signal R″. It is a diagram showing a first amplitude characteristic (solid line) and a second amplitude characteristic (broken line) obtained for. 10(a) and 10(b), the vertical axis indicates the level (unit: dB) and the horizontal axis indicates the frequency (unit: Hz).

Phase control section 116E calculates the level difference between the first amplitude characteristic and the second amplitude characteristic obtained for frequency spectrum signal L″ for each frequency spectrum, and accumulates the calculated level difference for each frequency spectrum. Further, the phase control unit 116E calculates the level difference between the first amplitude characteristic and the second amplitude characteristic obtained for the frequency spectrum signal R″ for each frequency spectrum, and accumulates the calculated level difference for each frequency spectrum. do. The phase control unit 116E compares these cumulative values and detects the speaker corresponding to the larger cumulative value as the speaker that satisfies a predetermined condition (step S21). In this way, the phase control unit 116E operates as a detection unit that detects a speaker that satisfies a predetermined condition from among a plurality of speakers based on the first amplitude characteristic and the second amplitude characteristic obtained for each speaker. .

FIG. 11(a) is a diagram showing the level difference for each frequency spectrum between the first amplitude characteristic and the second amplitude characteristic obtained for the frequency spectrum signal L″, and FIG. 11(b) is a diagram showing the level difference for each frequency spectrum signal FIG. 10 is a diagram showing the first amplitude characteristic, the second amplitude characteristic, and the level difference for each frequency spectrum obtained for R″; 11(a) and 11(b), the vertical axis indicates the level (unit: dB) and the horizontal axis indicates the frequency (unit: Hz).

Here, the first amplitude characteristic is obtained by phase-controlling the frequency spectrum signal to be processed and synthesizing it with another frequency spectrum signal, and the second amplitude characteristic is the frequency spectrum to be processed It was obtained by combining the signal with other frequency spectrum signals without phase control. Therefore, the cumulative value of this level difference is a value that indicates the effect of phase-controlling the frequency spectrum signal to be processed (the effect of increasing the level by reducing the destructive interference of sound between speakers at the listening position). I can say. A higher cumulative value indicates a higher effect.

The cumulative value of level differences shown in FIG. 11(a) is 782, and the cumulative value of level differences shown in FIG. 11(b) is 2,404. Since the accumulated value obtained for the frequency spectrum signal R" is high, it is possible to obtain a higher effect (weakening of the sound between the speakers at the listening position) by performing the phase adjustment processing based on the speaker SP _FR corresponding to the frequency spectrum signal R". The effect of increasing the level due to the reduction of interfering interference is obtained, and it is possible to improve the bias of the sound image localization and suppress the deterioration of sound quality and the decrease in sound pressure due to the interference between the sounds output from each speaker. .

Depending on the arrangement of the speakers and the environment inside the vehicle, the sound traveling from the speaker SP _FR to the listening position may be suppressed for a longer period of time due to the effects of sound reflection, shielding, interference, and the like. As an example, consider the case where the impulse response R' in FIG. 5(b) is at a suppressed level for a period of up to 5.0 msec. Also in this case, since the distance between the speaker SP _FR and the listening position (driver's seat) is the shortest, the sound from the speaker SP _FR reaches the listening position in a shorter time than the sound from the speaker SP _FL . (The impulse response R' rises faster than the impulse response L'). Therefore, in the conventional time alignment, the sound from the speaker SP _FR is delayed in order to improve the imbalance of sound image localization.

However, the rising portion of impulse response R' is at a suppressed level for periods up to 5.0 msec. Since this suppressed level sound is weak level sound, it cannot be said that it is a practical level sound that substantially contributes to the localization of the sound image. A practical level of sound from the speaker SP _FR , which substantially contributes to the localization of the sound image, reaches the listening position after more than 5.0 msec. On the other hand, looking at FIG. 5(a), the practical level sound from the speaker SP _FL , which substantially contributes to the localization of the sound image, reaches the listening position at 4.1 msec.

With conventional time alignment, a speaker with a practical level of sound that substantially contributes to the localization of the sound image takes a long time to reach the listening position (in this example, the speaker simply has a fast rise in impulse response). is set as the speaker that gives the delay. Therefore, with the conventional time alignment, it is difficult to sufficiently improve the bias of sound image localization.

On the other hand, in the present embodiment, the speaker used as the reference when executing the phase adjustment process is used as described above to achieve a higher effect (the level is increased by reducing the destructive interference of the sound between the speakers at the listening position). By detecting whether or not it is possible to obtain an increased effect), even in the special listening environment of a vehicle interior, it is possible to sufficiently improve the bias in the localization of the sound image, and to prevent deterioration in sound quality due to interference between the sounds output from each speaker. and sound pressure drop can be suppressed.

The phase control unit 116E obtains the synthesis result for each frequency spectrum obtained for the speaker (hereinafter referred to as the “reference speaker”) detected in step S21 (in this embodiment, the synthesis result for each frequency spectrum obtained for the speaker SP _FR) . 8B), when the phase of the sound from the speaker SP _FR and the phase of the sound from the speaker SP _FL are opposite in phase at the listening position, the frequency spectrum signal for each frequency spectrum A phase adjustment amount (first phase adjustment data) is obtained (step S22).

_FIG . 12 shows the phase adjustment amount for each frequency spectrum of the frequency spectrum signal _R ″ (first 12, the vertical axis indicates the phase adjustment amount (unit: degree) and the horizontal axis indicates the frequency (unit: Hz).

As shown in FIG. 4, the calculator 116 has a phase shifter 116F.

The phase shifter 116F determines, for each frequency spectrum, a phase adjustment amount for adjusting the phase of the sound signal output to the reference speaker according to the first phase adjustment data (see FIG. 12) (step S23). . Specifically, the phase adjustment amount for each frequency spectrum is determined according to the following equation.

Phs=+90° when |Phc|≦90°
Phs=0° when |Phc|>90°
Phc: phase adjustment amount obtained in step S22 Phs: phase adjustment amount determined in step S23

FIG. 13 is a diagram showing the phase adjustment amount for each frequency spectrum determined in step S23. In FIG. 13, the vertical axis indicates the phase adjustment amount (unit: degree), and the horizontal axis indicates the frequency (unit: Hz).

As shown in FIG. 4, the calculator 116 has a smoothing processor 116G.

The smoothing processor 116G smoothes the phase adjustment amount for each frequency spectrum input from the phase shifter 116F on the frequency axis (step S24). As a result, phase adjustment data (second phase adjustment data for the reference speaker) for adjusting the phase of the sound signal output to the reference speaker for each frequency spectrum is obtained.

FIG. 14 is a diagram showing the phase adjustment amount (second phase adjustment data for the reference speaker) after smoothing processing by the smoothing processing section 116G. In FIG. 14, the vertical axis indicates the phase adjustment amount (unit: degree), and the horizontal axis indicates the frequency (unit: Hz). The smoothing processor 116G uses an 8-tap FIR (Finite Impulse Response) filter to smooth the phase adjustment amount for each frequency spectrum input from the phase shifter 116F.

Smoothing processing by the smoothing processing unit 116G suppresses rapid phase changes in the frequency domain. Therefore, when a sound whose phase is adjusted using the phase adjustment data is output, the generation of harmonics due to a sudden change in phase is suppressed, and abnormal noise due to such harmonics is suppressed.

As shown in FIG. 4, the calculator 116 has a phase inverter 116H.

The phase inverting unit 116H inverts the phase of the phase adjustment amount after the smoothing process (second phase adjustment data for the reference speaker) obtained in step S24, so that the other speaker (in this embodiment, A phase adjustment amount (second phase adjustment data for other speakers) for each frequency spectrum for adjusting the phase of the sound signal output to the speaker SP _FL is obtained (step S25).

FIG. 15 is a diagram showing second phase adjustment data for another speaker obtained by the phase inverter 116H. In FIG. 15, the vertical axis indicates the phase adjustment amount (unit: degree), and the horizontal axis indicates the frequency (unit: Hz).

As shown in FIGS. 14 and 15, the second phase adjustment data for the reference speaker is phase adjustment for each frequency spectrum in accordance with the phase adjustment amount (first phase adjustment data) that is opposite in phase. The amount is set in the range of 0 degrees to 90 degrees, and the second phase adjustment data for other speakers is the phase adjustment amount (first phase adjustment data) that is opposite in phase. is set in the range of 0 degrees to -90 degrees.

In the present embodiment, the second phase adjustment data for each speaker is calculated based on the phase adjustment amount (first phase adjustment data) having the opposite phase, and the difference between the phase adjustment amounts is 180%. Since the second phase adjustment data for each speaker is calculated so as to be within 180 degrees (in other words, the difference in phase adjustment amount given to the sound signal output to each speaker is 180 in each frequency spectrum). (because the second phase adjustment data for each speaker is calculated so as to be within the degree), the position of the driver's seat that is asymmetric with respect to the position of the pair of speakers SP _FR and SP _FL , and the position of the driver's seat that is also asymmetric with respect to the position of the pair of speakers In both the position of the passenger seat, which is asymmetrical with respect to the position of the speakers SP _FR and SP _FL , it is possible to reduce the sound interference between the speakers due to the opposite phase, improve the localization, and improve the localization. Degradation of sound quality and reduction of sound pressure can be suppressed.

In this way, the phase control section 116E, the phase shift section 116F, the smoothing processing section 116G, and the phase inversion section 116H are configured to reduce the attenuation due to sound interference between multiple speakers in each frequency spectrum at multiple listening positions. Secondly, it operates as a generator that generates second phase adjustment data for adjusting the phase of the sound signal output to each speaker for each frequency spectrum.

The control section 100 sets the second phase adjustment data for each speaker in the phase adjustment section 110 (step S26). Using the second phase adjustment data, the phase adjustment section 110 operates as an adjustment section that adjusts the phase of the sound signal input from the sound source and output to each speaker for each frequency spectrum.

Next, the operation of reproducing the sound signal input from the sound source using the second phase adjustment data set in the phase adjustment section 110 will be described.

The recording medium reproducing unit 108 receives sound signals S _R and S _L (hereinafter referred to as “audio signals S _R and S _L ”) input from sound sources such as CDs (Compact Discs) and DVDs (Digital Versatile Discs). Reproduce. The control unit 100 outputs the audio signals S _L and S _R reproduced by the recording medium reproducing unit 108 to the phase adjusting unit 110 .

The phase adjustment unit 110 adjusts the phase of the audio signal output to each speaker for each frequency spectrum and outputs the audio signal. The audio signals S _R and S _L output from the phase adjustment section 110 are output to the vehicle interior from the speakers SP _FR and SP _FL through the amplification section 112, respectively.

FIG. 16 is a block diagram showing the configuration of phase adjustment section 110. As shown in FIG. As shown in FIG. 16, phase adjustment section 110 has FFT (Fast Fourier Transform) section 110A, complex multiplication section 110B and IFFT (Inverse Fast Fourier Transform) section 110C.

The FFT unit 110A performs overlap processing and weighting with a window function on the audio signals S _R and S _L input from the control unit 100, and then converts them from the time domain to the frequency domain by STFT (Short-Term Fourier Transform). , and outputs a frequency spectrum signal composed of amplitude and phase to the complex multiplier 110B. The overlap processing and window function are intended to reduce noise by gradually changing the amount of phase adjustment when the localization position is changed by user operation (for example, when changing from the driver's seat to the front passenger's seat). be.

In this embodiment, the FFT section 110A has a sampling frequency of 44.1 kHz. The FFT section 110A has a Fourier transform length of 8,192 samples, an overlap length of 6,144 samples, and a Hanning window as a window function. The FFT unit 110A performs STFT while shifting the time by 2,048 samples, thereby dividing the frequency region from 0 Hz to 22.05 kHz of the Nyquist frequency in increments of 5.38 Hz, resulting in a total of 4,097 frequency spectrum signals. to get

The second phase adjustment data input from the control unit 100 is set in the complex multiplication unit 110B. The complex multiplication unit 110B performs complex multiplication on the frequency spectrum signal input from the FFT unit 110A for each speaker channel based on the second phase adjustment data, and outputs audio to the speaker of each channel. Adjust the phase of the signal for each frequency spectrum.

The IFFT unit 110C converts the phase-adjusted frequency spectrum signal input from the complex multiplication unit 110B2 from the frequency domain to the time domain signal by the ISTFT, weights the converted signal using a window function, and performs overlap addition. , to the amplifier 112 .

17 to 20 show specific examples of phase adjustment for each speaker channel. In this example, it is assumed that the audio signal is a monaural impulse signal with a frequency domain of 1 kHz. Interaural phase difference affects localization in the low frequency range below 750 Hz, interaural phase difference and interaural level difference affect localization in the low and mid frequency range of 750 Hz to 1.5 kHz, and above 1.5 kHz. It is known that the interaural level difference affects localization in the mid-to-high range (see, for example, Japanese Unexamined Patent Application Publication No. 2004-325284). Therefore, the frequency range to be phase-adjusted is set to 1 kHz here. Since wavelengths of 1 kHz or less are relatively long, the interaural phase difference is relatively small. Therefore, here, the sounds reaching the left and right ears of the listener are assumed to be the same, and the measurement point for each seat (listening position where the microphone MIC is installed) is one point.

17(a) and 17(b) are diagrams showing time characteristics of audio signals picked up by a microphone MIC installed in the driver's seat. Specifically, FIG. 17(a) shows a case where audio signals not subjected to the phase adjustment processing according to the present embodiment are simultaneously output from the speakers SP _FR and SP _FL (hereinafter referred to as “example without control”). ), and is a diagram showing time characteristics of an audio signal picked up by a microphone MIC installed in the driver's seat. FIG. 17(b) shows when the audio signals subjected to the phase adjustment processing according to the present embodiment are simultaneously output from the speakers SP _FR and SP _FL (hereinafter referred to as "phase adjustment example"), the FIG. 4 is a diagram showing time characteristics of an audio signal picked up by an installed microphone MIC; 17(a) and 17(b), the vertical axis indicates amplitude and the horizontal axis indicates time (unit: sec).

FIGS. 18(a) and 18(b) are diagrams showing time characteristics of audio signals picked up by a microphone MIC installed on the passenger's seat. Specifically, FIG. 18(a) is a diagram showing the time characteristics of an audio signal picked up by the microphone MIC installed on the front passenger's seat in an example without control. FIG. 18(b) is a diagram showing time characteristics of an audio signal picked up by a microphone MIC installed on the front passenger seat in an example of phase adjustment. 18A and 18B, the vertical axis indicates amplitude and the horizontal axis indicates time (unit: sec).

Comparing FIG. 17A and FIG. 17B, it can be seen that the phase adjustment processing according to the present embodiment is applied to the audio signal, resulting in a higher amplitude than the case where the audio signal is not subjected to the phase adjustment processing according to the present embodiment. becomes larger. 18A and 18B, by applying the phase adjustment processing according to the present embodiment to the audio signal, the phase adjustment processing according to the present embodiment can be applied to the audio signal even in the front passenger seat. It can be seen that the amplitude is larger than that in the case where no heat treatment is applied. This is because by subjecting the audio signal to the phase adjustment process according to the present embodiment, at each listening position (driver's seat, front passenger's seat), weakening due to sound interference between the speaker SP _FR and the speaker SP _FL is reduced. be.

FIG. 19 is a diagram showing the frequency characteristics (thin solid line) of an audio signal with no control and the frequency characteristics (thick solid line) of an audio signal with an example of phase adjustment, picked up by a microphone MIC installed in the driver's seat. . FIG. 20 is a diagram showing the frequency characteristics (thin solid line) of an audio signal with no control and the frequency characteristics (thick solid line) of an audio signal with phase adjustment, picked up by a microphone MIC installed in the front passenger seat. . 19 and 20, the vertical axis indicates level (unit: dB) and the horizontal axis indicates frequency (unit: Hz).

As shown in FIGS. 19 and 20, in the example of phase adjustment according to the present embodiment, the level is large over almost the entire range compared to the example without control, and at both listening positions of the driver's seat and passenger seat , weakening due to sound interference between the speaker SP _FR and the speaker SP _FL is reduced compared to the case without control. Also, the occurrence of dips in the frequency domain is substantially suppressed. Therefore, in the example of phase adjustment according to the present embodiment, as compared with the example without control, the bias in sound image localization is improved at both the listening positions of the driver's seat and the front passenger seat, and the difference between the speaker SP _FR and the speaker SP _FL is improved. It can be seen that the sound quality deterioration and the sound pressure drop due to the sound interference of the

Note that the frequency components of voice and music are concentrated in the low-mid range. Therefore, when targeting audio signals such as voice and music (monaural signals in the low-mid range of 1 Hz or less as shown here), the localization of the sound image can be sufficiently improved by simply adjusting the phase of the low-mid range, and the dip can be reduced. It is possible to suppress the deterioration of sound quality and the decrease in sound pressure due to the occurrence of noise.

The foregoing is a description of exemplary embodiments of the present invention. Embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical idea of the present invention. For example, the embodiment of the present application also includes the content of appropriately combining the examples and the like explicitly specified in the specification or the obvious examples and the like.

The phase adjustment amount for each frequency spectrum determined by the phase shifter 116F in step S23 is not limited to that of the above embodiment. The phase shifter 116F may determine the phase adjustment amount for each frequency spectrum according to the following equation, for example.

Phs=Phc+90° when |Phc|≦90°
Phs = Phc - 90° when |Phc| > 90°

Frequency characteristic (thin solid line) and phase of an audio signal without control picked up by the microphone MIC installed in the driver's seat when the phase shifter 116F determines the phase adjustment amount for each frequency spectrum according to the above formula. FIG. 21 shows the frequency characteristics (thick solid line) of the audio signal in the adjustment example. In this case, FIG. 22 shows the frequency characteristics (thin solid line) of an audio signal with no control and the frequency characteristics (thick solid line) of an audio signal with an example of phase adjustment, which are picked up by the microphone MIC installed in the front passenger seat. shown in 21 and 22, the vertical axis indicates level (unit: dB) and the horizontal axis indicates frequency (unit: Hz).

As shown in FIGS. 21 and 22, in this case as well, in the example of phase adjustment, the level is greater over almost the entire range than in the case of no control, and at both the listening positions of the driver's seat and the front passenger's seat, It can be seen that weakening due to sound interference between the speaker SP _FR and the speaker SP _FL is reduced compared to the case without control. Also, the occurrence of dips in the frequency domain is substantially suppressed. Therefore, in this case as well, in _the example of phase adjustment, compared to the example without control, the bias in sound image localization is improved at both the listening positions of the driver's seat and the front passenger's _seat . It can be seen that deterioration in sound quality and reduction in sound pressure due to sound interference can be suppressed.

In the above embodiment, in step S22, the phase control unit 116E controls the frequency of the frequency spectrum signal when the phase of the sound from the speaker SP _FR and the phase of the sound from the speaker SP _FL are opposite in phase at the listening position. Although the phase adjustment amount for each spectrum is obtained as the first phase adjustment data, in another embodiment, the phase of the sound from the speaker SP _FR and the phase of the sound from the speaker SP _FL are in phase at the listening position. The phase adjustment amount for each frequency spectrum of the frequency spectrum signal may be obtained as the first phase adjustment data when .

In the above embodiment, the acoustic device 10 has the phase adjustment data generation function (phase control device), but the present invention also includes an acoustic device without the phase adjustment data generation function. This acoustic device holds in advance second phase adjustment data for each speaker generated, for example, at a manufacturing factory, etc., and uses the second phase adjustment data to input from the sound source to each speaker. By adjusting the phase of the output sound signal for each frequency spectrum, it is configured to reduce the weakening due to sound interference between a plurality of speakers at a plurality of listening positions in each frequency spectrum.

In another embodiment, the phase adjustment unit 110 Fourier transforms the phase adjustment amount for each frequency spectrum to generate FIR filter coefficients, and performs phase control by processing in the time domain using the FIR filter. The audio signal output to the speaker may be phase-adjusted for each frequency spectrum. In addition, the phase adjustment unit 110 performs division processing for each frequency band based on the phase adjustment amount for each frequency spectrum, and uses an all-pass filter using a secondary IIR (Infinite Impulse Response) filter or the like to determine the target of phase control. Phase adjustment may be performed on the audio signal output to the speaker that is to be.

In the above embodiment, the processing when the impulse response is measured at the driver's seat has been described, but the same processing may be performed for each seat. In this case, the control unit 100 may hold, as preset data, second phase adjustment data for each speaker generated when impulse responses are measured at each seat. By operating the operation unit 104 to select preset data, the listener can arbitrarily switch the second phase adjustment data for improving the bias of sound image localization.

In the above embodiment, the processing for the front speakers has been described, but if another speaker (for example, a rear speaker) is installed in the vehicle, the same processing is performed on the rear speaker side. good too.

1 Acoustic system 10 Acoustic device 100 Control unit 102 Display unit 104 Operation unit 106 Measurement signal generation unit 108 Recording medium reproduction unit 110 Phase adjustment unit 110A FFT unit 110B Complex multiplication unit 110C IFFT unit 112 Amplification unit 114 Signal recording unit 116 Calculation unit 116A, 116B measurement section 116C, 116D Fourier transform section 116E phase control section 116F phase shift section 116G smoothing processing section 116H phase inversion section

Claims (16)

a measurement unit that measures the impulse response of each sound signal output from each of the plurality of speakers and picked up at a predetermined listening position at non-interfering timing;
a Fourier transform unit for obtaining a frequency spectrum signal of the impulse response for each speaker by Fourier transforming the measured impulse response of the sound signal from each speaker;
Predetermined phase control is performed on each of the frequency spectrum signals obtained by the Fourier transform section, and a first amplitude characteristic is obtained by synthesizing with other frequency spectrum signals not subjected to the predetermined phase control. an amplitude characteristic calculator that obtains a second amplitude characteristic by synthesizing with the other frequency spectrum signal without performing the phase control;
a detection unit that detects a speaker satisfying a predetermined condition from among the plurality of speakers based on the first amplitude characteristic and the second amplitude characteristic obtained for each speaker;
At a plurality of listening positions including the predetermined listening position, the plurality of a second phase adjustment for adjusting the phase of the sound signal output to each of the plurality of speakers for each frequency spectrum such that the destructive effect due to the sound interference between the speakers is reduced in each frequency spectrum; a generator that generates data for
comprising
Phase controller. The detection unit is
calculating a level difference between the first amplitude characteristic and the second amplitude characteristic for each speaker;
comparing values corresponding to the level differences calculated for each speaker;
detecting a speaker that satisfies the predetermined condition based on the result of the comparison;
The phase control device according to claim 1. The detection unit is
calculating the level difference for each frequency spectrum;
accumulating the calculated level difference for each frequency spectrum,
Comparing the cumulative values of the level differences obtained for each of the speakers,
detecting the speaker with the largest cumulative value as the speaker that satisfies the predetermined condition;
3. The phase control device according to claim 2. The amplitude characteristic calculator,
Perform the following processes (1) to (5) for each frequency spectrum signal obtained by the Fourier transform unit,
(1) changing the phase of the frequency spectrum signal to be processed, and synthesizing the frequency spectrum signal to be processed and the other frequency spectrum signal each time the phase is changed;
(2) obtaining a phase adjustment amount of the sound signal from the speaker for each frequency spectrum based on the result of the synthesis;
(3) complex-multiplying the obtained phase adjustment amount for each frequency spectrum and the frequency spectrum signal to be processed;
(4) obtaining a first amplitude characteristic by combining the complex-multiplied frequency spectrum signal and the other frequency spectrum signal;
(5) obtaining a second amplitude characteristic by synthesizing the frequency spectrum signal to be processed and the other frequency spectrum signal without changing the phase;
The phase control device according to any one of claims 1 to 3. The first data for phase adjustment is
to the detected speaker so that the phase of the sound output from the detected speaker and the phase of the sound output from the other speaker are in phase or opposite in phase in each of the frequency spectra at the listening position Data for adjusting the phase of the output sound for each frequency spectrum,
The phase control device according to any one of claims 1 to 4. The generating unit
Based on the first phase adjustment data, a phase adjustment amount to be applied to a sound signal output to each of the plurality of speakers is calculated for each frequency spectrum,
obtaining the calculated phase adjustment amount for each frequency spectrum as the second phase adjustment data;
6. The phase control device according to claim 5. The generating unit
calculating the phase adjustment amount so that the difference in the phase adjustment amount given to the sound signal output to each of the plurality of speakers is within 180 degrees in each of the frequency spectra;
7. The phase control device according to claim 6. An acoustic device having the phase control device according to any one of claims 1 to 7 and outputting sound signals input from a sound source to the plurality of speakers,
An adjusting unit that adjusts the phase of the sound signal input from the sound source and output to each of the plurality of speakers for each frequency spectrum, using the second phase adjustment data,
sound device. A computer implemented phase control method comprising:
a measurement step of measuring the impulse response of each sound signal output from each of a plurality of speakers and picked up at a predetermined listening position at non-interfering timing;
a Fourier transform step of obtaining a frequency spectrum signal of the impulse response for each speaker by Fourier transforming the measured impulse response of the sound signal from each speaker;
Predetermined phase control is performed on each of the frequency spectrum signals obtained in the Fourier transform step, and the first amplitude characteristic is obtained by synthesizing with the other frequency spectrum signals not subjected to the predetermined phase control. an amplitude characteristic calculating step of obtaining a second amplitude characteristic by synthesizing with the other frequency spectrum signal without performing the phase control;
a detection step of detecting a speaker satisfying a predetermined condition from among the plurality of speakers based on the first amplitude characteristic and the second amplitude characteristic obtained for each speaker;
At a plurality of listening positions including the predetermined listening position, the plurality of a second phase adjustment for adjusting the phase of the sound signal output to each of the plurality of speakers for each frequency spectrum such that the destructive effect due to the sound interference between the speakers is reduced in each frequency spectrum; a generation step that generates data for
including,
Phase control method. In the detection step,
calculating a level difference between the first amplitude characteristic and the second amplitude characteristic for each speaker;
comparing values corresponding to the level differences calculated for each speaker;
detecting a speaker that satisfies the predetermined condition based on the result of the comparison;
The phase control method according to claim 9. In the detection step,
calculating the level difference for each frequency spectrum;
accumulating the calculated level difference for each frequency spectrum,
Comparing the cumulative values of the level differences obtained for each of the speakers,
detecting the speaker with the largest cumulative value as the speaker that satisfies the predetermined condition;
The phase control method according to claim 10. In the amplitude characteristic calculation step,
Perform the following processes (1) to (5) for each of the frequency spectrum signals obtained in the Fourier transform step,
(1) changing the phase of the frequency spectrum signal to be processed, and synthesizing the frequency spectrum signal to be processed and the other frequency spectrum signal each time the phase is changed;
(2) obtaining a phase adjustment amount of the sound signal from the speaker for each frequency spectrum based on the result of the synthesis;
(3) complex-multiplying the obtained phase adjustment amount for each frequency spectrum and the frequency spectrum signal to be processed;
(4) obtaining a first amplitude characteristic by combining the complex-multiplied frequency spectrum signal and the other frequency spectrum signal;
(5) obtaining a second amplitude characteristic by synthesizing the frequency spectrum signal to be processed and the other frequency spectrum signal without changing the phase;
The phase control method according to any one of claims 9 to 11. The first data for phase adjustment is
to the detected speaker so that the phase of the sound output from the detected speaker and the phase of the sound output from the other speaker are in phase or opposite in phase in each of the frequency spectra at the listening position Data for adjusting the phase of the output sound for each frequency spectrum,
The phase control method according to any one of claims 9 to 12. In the generating step,
Based on the first phase adjustment data, a phase adjustment amount to be applied to a sound signal output to each of the plurality of speakers is calculated for each frequency spectrum,
obtaining the calculated phase adjustment amount for each frequency spectrum as the second phase adjustment data;
14. The phase control method according to claim 13. In the generating step,
calculating the phase adjustment amount so that the difference in the phase adjustment amount given to the sound signal output to each of the plurality of speakers is within 180 degrees in each of the frequency spectra;
15. The phase control method according to claim 14. When outputting a sound signal input from a sound source to the plurality of speakers, the sound signal input from the sound source and output to each of the plurality of speakers using the second phase adjustment data. for each of said frequency spectrums.
The phase control method according to any one of claims 9 to 15.

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