JP2006262015A - Sound field characteristic measuring method, sound field characteristic measuring system, amplifier and sound field characteristic measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound field characteristic measuring method, a sound field characteristic measuring system, an amplifier and a sound field characteristic measuring instrument capable of reducing labor and the time required for measuring the characteristics of a sound field generated by a plurality of speakers. <P>SOLUTION: A measuring signal generation part (signal generation means) generates a plurality of sound signals modulated by pseudo random orthogonal codes corresponding to the plurality of speakers L, C, R, Ls, Rs and SW respectively, and generates input sound signals based on the sound for which the sounds generated by the respective speakers are overlapped on the basis of the respective sound signals. In a sound field measuring part (sound field measuring means) 14, the correlation computation of the input sound signals after prescribed elapsed time from the start of measurement and original sound signals corresponding to the respective speakers is performed while changing the elapsed time. From pseudo randomness and orthogonality, the responses of the sound signals corresponding to the respective speakers are individually obtained, the results of the correlation computation are compared with each other, and the relative delay time of the sound between the speakers is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sound field characteristic measuring method, a sound field characteristic measuring system, an amplifying apparatus, and a sound field characteristic measuring apparatus that measure the characteristics of a sound field formed by a plurality of speakers generating sound.

  As a theater, home, or in-vehicle audio system, a multi-channel sound system is used in which a plurality of speakers are installed in front and rear of a viewer, and a channel is assigned to each speaker to reproduce sound in multiple channels. Yes. In such an acoustic system, there is no possibility of generating an inappropriate sound field such as a difference in the arrival time of sound from the left and right speakers to the viewer, or a difference in the dynamic range of sounds heard from the left and right speakers. It is necessary to adjust the sound field characteristics. The characteristics of the sound field generated by the acoustic system vary greatly depending on the installation status of the acoustic system, such as the shape of the room in which the acoustic system is installed or the layout in the vehicle. Therefore, in order to achieve good sound field characteristics, the sound field is once measured with the sound system installed, and the position of each speaker or the delay time between the input signals of each channel is determined based on the measurement result. To adjust the sound field characteristics.

Patent Document 1 discloses a technique for measuring the characteristics of a sound field generated by an acoustic system in order to adjust the sound field characteristics of the acoustic system. In this technology, microphones are installed immediately before the speaker and at the viewing position, and a trigger signal is generated when the microphone immediately before the speaker receives sound. The delay time is measured by accumulating. When measuring the characteristics of a sound field with a 5.1 channel or other multi-channel acoustic system, sound signals are output sequentially to each channel, and the sound signals are sequentially reproduced as sound by speakers corresponding to each channel. The sound field is measured with a microphone at the viewing position.
JP 2002-101500 A

  However, the technique disclosed in Patent Document 1 has a problem that a microphone for generating a trigger signal is required in addition to the microphone that measures the characteristics of the sound field at the viewing position. In addition, every time the sound field is measured in each channel, it is necessary to repeat the operation of installing a microphone for trigger generation immediately before the speaker corresponding to the channel and outputting the music signal to the channel to measure the characteristics of the sound field. . Therefore, there is a problem that much labor and time are required to measure the characteristics of the sound field in a multi-channel acoustic system.

  The present invention has been made in view of such circumstances, and an object thereof is to measure sound fields generated by an acoustic system including a plurality of speakers by using a single microphone. An object of the present invention is to provide a sound field characteristic measurement method, a sound field characteristic measurement system, an amplification device, and a sound field characteristic measurement device that can reduce labor and time required for field measurement.

  A sound field characteristic measuring method according to a first aspect of the present invention is a method for measuring characteristics of a sound field composed of sound generated by a plurality of speakers using a microphone that collects the sound, and is a pseudo-random code sequence orthogonal to each other. Generating a plurality of audio signals modulated with pseudo-random orthogonal codes corresponding to each of a plurality of speakers among the plurality of pseudo-random orthogonal codes, and outputting the audio signals corresponding to the generated speakers to the speakers, The microphone collects sound in which sounds generated by a plurality of speakers are overlapped based on the output sound signal, generates an input sound signal based on the sound collected by the microphone, and generates an input sound signal Correlation calculation between a portion after a predetermined elapsed time and an audio signal modulated with a pseudo-random orthogonal code corresponding to each speaker is performed by changing the elapsed time. To determine the elapsed time value at which the peak of the correlation calculation output value corresponding to each speaker is obtained, and based on the relative difference between the speakers corresponding to each speaker, The relative delay time of the generated voice is obtained.

  A sound field characteristic measuring system according to a second aspect of the invention includes a plurality of speakers that generate sound based on a sound signal, sound output means that outputs sound signals corresponding to each speaker to each speaker, and the sound output means includes the sound output means. A signal generating means for generating a plurality of audio signals to be output to a plurality of speakers, a microphone for collecting sounds generated by the plurality of speakers, and generating an input audio signal based on the collected sounds; In a sound field characteristic measuring system comprising: a sound field measuring unit that measures a characteristic of a sound field composed of sounds generated by the plurality of speakers based on an input sound signal generated by a microphone; Among a plurality of pseudo-random orthogonal codes that are orthogonal to each other, a plurality of pseudo-random orthogonal codes that correspond to each of a plurality of speakers The microphone is configured to generate a voice signal, and the microphone is configured to generate an input voice signal based on a voice in which voices generated by a plurality of speakers overlap with each other, and the sound field measurement unit includes: Correlation calculation means for performing a correlation calculation between a portion after a predetermined elapsed time of the input audio signal generated by the microphone and an audio signal modulated with a pseudo-random orthogonal code corresponding to each speaker while changing the elapsed time; Based on the relative difference between the means for obtaining an elapsed time value at which the peak of the output value of the correlation calculation corresponding to each speaker is obtained, and the value corresponding to each speaker obtained by the means, between the speakers, Means for obtaining a relative delay time of sound generated by a plurality of speakers.

  In the sound field characteristic measurement system according to a third aspect of the invention, the signal generation means is configured to generate an audio signal for causing a speaker to generate sound including a plurality of frequency components in an audible range, and the sound field The measurement means further includes frequency characteristic calculation means for obtaining a frequency characteristic of the sound field by performing a Fourier transform on a function of the output value of the correlation calculation corresponding to each speaker with respect to an elapsed time.

  In the sound field characteristic measurement system according to a fourth aspect of the present invention, the frequency characteristic calculation means includes the function in which the peak of the output value is discretely included in an elapsed time range in which the absolute value of the peak value is equal to or greater than a predetermined value. It is characterized by being configured to perform Fourier transform.

  The sound field characteristic measurement system according to a fifth aspect of the present invention further comprises amplification means for amplifying the audio signal corresponding to each speaker generated by the signal generation means at a different amplification factor between the speakers according to a predetermined setting, and the correlation calculation The means includes means for amplifying the output value of the correlation operation corresponding to each speaker at an amplification factor that is inversely proportional to the amplification factor that differs between the speakers when the amplification unit amplifies the audio signal.

  In the sound field characteristic measurement system according to a sixth aspect of the invention, the signal generation means reads data from a recording medium on which data for generating an audio signal corresponding to each speaker is recorded, and outputs an audio signal based on the read data. Based on the read data when the data is read from a recording medium for recording data for generating a plurality of audio signals modulated by pseudo random orthogonal codes corresponding to each of a plurality of speakers. And generating a sound signal modulated with a pseudo-random orthogonal code corresponding to each speaker.

  An amplifying apparatus according to a seventh aspect of the present invention includes an audio output unit that outputs an audio signal to each of a plurality of external speakers that generate audio based on the audio signal, and a plurality of audio signals that are output to the plurality of speakers. Signal generating means for generating, input sound signal receiving means for receiving an input sound signal generated based on sound collected by an external microphone that picks up sound generated by the plurality of speakers, and input sound signal receiving means And a sound field measuring means for measuring characteristics of a sound field composed of sounds generated by the plurality of speakers based on the input sound signals received by the plurality of speakers, wherein the signal generating means are pseudo-random and orthogonal to each other A plurality of audio signals modulated with a pseudo-random orthogonal code corresponding to each of a plurality of external speakers among a plurality of pseudo-random orthogonal codes that are code sequences The input audio signal receiving means is configured to receive an input audio signal generated by an external microphone based on an audio in which audio generated by the plurality of speakers overlaps; The sound field measuring means performs a correlation operation between a portion of the input sound signal received by the input sound signal receiving means after a predetermined elapsed time and a sound signal modulated with a pseudo-random orthogonal code corresponding to each external speaker, Correlation calculation means for changing the elapsed time, means for obtaining an elapsed time value at which a peak of the output value of the correlation calculation corresponding to each external speaker is obtained, and each external speaker obtained by the means Means for determining a relative delay time of sound generated by a plurality of external speakers based on a relative difference between the corresponding values of the speakers. The features.

  According to an eighth aspect of the invention, the signal generating means reads data from a recording medium on which data for generating an audio signal corresponding to each external speaker is recorded, and generates an audio signal based on the read data. When the data is read from a recording medium that records data for generating a plurality of audio signals modulated with pseudo random orthogonal codes corresponding to each of a plurality of external speakers, the read data Based on this, it is configured to generate an audio signal modulated with a pseudo-random orthogonal code corresponding to each external speaker.

  An amplifying apparatus according to a ninth aspect of the present invention is an audio signal receiving means for receiving a plurality of audio signals for outputting to each of a plurality of external speakers generating sound based on the audio signal, and the audio signal receiving means An audio output unit that appropriately adjusts the received audio signal and outputs it to each external speaker; and an input audio signal that is generated based on the audio collected by an external microphone that collects the audio generated by the plurality of speakers An amplifying apparatus comprising: an input audio signal receiving unit that receives; and a sound field measuring unit that measures characteristics of a sound field composed of sounds generated by the plurality of speakers based on the input audio signal received by the input audio signal receiving unit. In the above, the audio signal receiving means is a pseudo-random orthogonal code sequence, and a plurality of pseudo-random orthogonal codes, each of a plurality of speakers. Each of a plurality of audio signals modulated by a corresponding pseudo-random orthogonal code is received, and the input audio signal receiving means is configured to receive an external microphone based on an audio obtained by overlapping the sounds generated by the plurality of speakers. The sound field measuring means is configured to receive a portion of the input sound signal received by the input sound signal receiving means after a predetermined elapsed time and a pseudo-random corresponding to each speaker. Correlation calculation means for performing a correlation calculation with an audio signal modulated with an orthogonal code while changing the elapsed time, and a value of an elapsed time at which a peak of the output value of the correlation calculation corresponding to each external speaker is obtained. And a plurality of external speakers based on a relative difference between the speaker and the value corresponding to each external speaker determined by the means. There characterized by having a means for obtaining a relative delay time of the sound to be generated.

  A sound field characteristic measuring apparatus according to a tenth aspect of the present invention is an apparatus for measuring the characteristics of a sound field composed of sound generated by a plurality of external speakers, wherein a plurality of pseudo random orthogonal codes that are pseudo-random and orthogonal code sequences are used. Input audio generated by an external microphone that collects audio that is generated by overlapping audio generated by each of the plurality of speakers based on a plurality of audio signals modulated by pseudo-random orthogonal codes corresponding to each of the plurality of speakers. Correlation calculation between a signal receiving means and a portion after a predetermined elapsed time of the input audio signal received by the means and an audio signal modulated with a pseudo-random orthogonal code corresponding to each external speaker changes the elapsed time. And a means for obtaining an elapsed time value at which a peak of the output value of the correlation calculation corresponding to each external speaker is obtained. And a means for obtaining a relative delay time of sound generated by a plurality of external speakers based on a relative difference between the speakers in the value corresponding to each external speaker obtained by the means. Features.

  In the first, second, seventh and tenth inventions, a plurality of audio signals modulated with pseudo-random orthogonal codes corresponding to the plurality of speakers are generated, and each speaker is generated based on the generated audio signals. The sound that overlaps the collected sound is collected by the microphone, the input sound signal based on the collected sound is generated, the input sound signal after the predetermined elapsed time from the start of the measurement, and the original sound signal corresponding to each speaker The relative delay time between the speakers is obtained from the elapsed time at which the peak value of the correlation calculation is obtained.

  In the third invention, by performing a Fourier transform on the function for the elapsed time of the output value of the correlation operation between the input audio signal after the predetermined elapsed time from the start of measurement and the original audio signal corresponding to each speaker, Obtain the frequency characteristics of the sound field, such as whether the frequency components are easily attenuated.

  In the fourth invention, when the frequency characteristic of the sound field corresponding to each speaker is obtained, the absolute value of the peak value of the correlation operation between the input sound signal and the sound signal corresponding to each speaker is the Fourier transform. Fourier transform is performed in a range that is equal to or greater than a predetermined value with sufficient intensity.

  In the fifth invention, the audio signal corresponding to each speaker generated by the signal generating means is amplified at different amplification factors between the speakers, and the output value of the correlation calculation between the input audio signal and the audio signal corresponding to each speaker. Is amplified at an amplification factor inversely proportional to the previous amplification factor.

  In the sixth, eighth and ninth inventions, an audio player capable of reading a recording medium for recording data for generating a plurality of audio signals modulated with pseudo random orthogonal codes corresponding to each speaker is used, and each speaker is used. The audio player is caused to function as signal generation means for generating an audio signal modulated with a pseudo-random orthogonal code corresponding to.

  In the first, second, seventh, and tenth inventions, a microphone for generating a trigger signal, which has been conventionally required, is unnecessary in addition to a microphone that collects sound at a viewing position. In addition, by using the orthogonality and pseudo-randomness of the audio signal corresponding to each speaker, it is possible to simultaneously measure the relative delay time of the sound field composed of the sound generated by a plurality of speakers using a single microphone. Therefore, the labor and time required for measuring the sound field can be reduced as compared with the conventional method in which the sound field measurement is repeated for each speaker.

  In the third invention, by using the orthogonality and pseudo-randomness of the audio signal corresponding to each speaker, the frequency characteristic of the sound field composed of the sound generated by a plurality of speakers can be obtained using a single microphone. Since measurement can be performed simultaneously, it is possible to reduce labor and time required for measuring the sound field, compared to the conventional method in which the sound field measurement is repeated for each speaker.

  In the fourth aspect of the invention, the absolute value of the peak value of the output value of the correlation calculation between the input audio signal and the audio signal corresponding to each speaker is in a range where the absolute value is not less than a predetermined value sufficient for Fourier transform. By performing the conversion, the frequency characteristic of the sound field can be calculated efficiently.

  In the fifth invention, an audio signal corresponding to a speaker that is likely to be attenuated in the sound field space is amplified in advance, and an output value of a correlation calculation between the input audio signal and the audio signal corresponding to each speaker is calculated in advance. By amplifying at an amplification factor that is inversely proportional to the amplification factor, it is possible to capture sound from a speaker that easily attenuates in the sound field space with good sensitivity and measure the sound field characteristics.

  In the sixth, eighth, and ninth inventions, an audio player reads a recording medium for recording data for generating a plurality of audio signals modulated with pseudo-random orthogonal codes corresponding to each speaker, and is recorded on each speaker. By adopting a configuration that can generate a corresponding audio signal, it is not necessary to provide a signal generating means separately from the audio player, so the configuration of the amplification device and the sound field characteristic measurement system can be simplified and the cost can be reduced. It becomes. In addition, the present invention has an excellent effect such that it is possible to more easily measure the sound field characteristics.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration of a sound field characteristic measurement system according to the first embodiment of the present invention. The sound field characteristic measuring system according to the present invention includes a plurality of speakers L (left), C (center), R (right), Ls (left surround), Rs (right surround), SW (subwoofer), and an optical disk or magnetic field. An audio system including an audio player 2 that reads data recorded on a recording medium such as a tape and generates an audio signal, and an amplifier 1 that appropriately adjusts the audio signal generated by the audio player 2 and outputs the audio signal to each speaker. The function of measuring the characteristics of the sound field generated by the acoustic system is provided. The speakers L, C, R, Ls, Rs, and SW are connected to the amplifying device 1 through signal lines of L channel, C channel, R channel, Ls channel, Rs channel, and SW channel, respectively. The audio is generated based on the audio signal output via the signal line. The acoustic system is installed in a theater, a home, an automobile, or the like, and the sound field characteristic measurement system of the present invention performs a process of measuring the sound field characteristic according to the installation state of the acoustic system.

  The amplifying apparatus 1 according to the present invention includes a control unit 12 that controls the entire amplifying apparatus 1, and L channel, C channel, R channel, Ls channel corresponding to each of the speakers L, C, R, Ls, Rs, and SW. An audio output unit (audio output means) 11 that performs processing to output audio signals for each channel in each of the Rs channel and the SW channel is provided. The audio player 2 is connected to the audio output unit 11 and is configured to input the generated audio signal to the audio output unit 11. The audio output unit 11 has a function of a multi-channel amplifier that individually amplifies the audio signal of each channel under the control of the control unit 12, and also has a function of applying various effects to the audio signal. The audio output unit 11 has a function of performing AD conversion or DA conversion of the audio signal as necessary in response to the difference between digital and analog audio signals to be input or output.

  The amplifying apparatus 1 includes a measurement signal generation unit (signal generation unit) 13 that generates an audio signal for measuring the sound field characteristics. The measurement signal generation unit 13 is connected to the audio output unit 11, generates an audio signal for measuring sound field characteristics corresponding to each of the speakers L, C, R, Ls, Rs, and SW, and generates the generated audio. The signal is input to the audio output unit 11. The sound output unit 11 outputs sound signals for measuring sound field characteristics corresponding to the speakers L, C, R, Ls, Rs, and SW input from the measurement signal generation unit 13 to each speaker, and the speaker L , C, R, Ls, Rs, and SW generate sound based on the output sound signal. The sound field characteristic measurement system includes a microphone M that collects sound generated by the speakers L, C, R, Ls, Rs, and SW, and the microphone M generates a sound signal from the sound, contrary to the speaker. The input voice signal is generated based on the collected voice. Further, the amplifying apparatus 1 includes a microphone input unit (input audio signal receiving unit) 15 that receives an input audio signal generated by the microphone M, and a process of measuring the characteristics of the sound field based on the input audio signal received by the microphone input unit 15. And a sound field measuring unit (sound field measuring means) 14 for performing the above.

  FIG. 2 is a block diagram illustrating an internal functional configuration of the measurement signal generation unit 13. The measurement signal generator 13 includes signal generators 131, 132, 133, 134, 135, and 136 that generate audio signals to the L channel, C channel, R channel, Ls channel, Rs channel, and SW channel, respectively. Yes. Each of the signal generation units 131, 132, 133, 134, 135, and 136 is connected to each of level correction units 13a, 13b, 13c, 13d, 13e, and 13f that amplify the generated audio signal. Each of the level correction units 13a, 13b, 13c, 13d, 13e, and 13f is connected to the audio output unit 11 through signal lines of L channel, C channel, R channel, Ls channel, Rs channel, and SW channel.

  The signal generators 131, 132, 133, 134, 135, and 136 generate a speech signal composed of a specific pseudo-random orthogonal code for each channel among a plurality of pseudo-random orthogonal codes that are pseudo-random and orthogonal to each other. It is the composition to do. FIG. 3 is a characteristic diagram illustrating an example of an audio signal. The signal shown in the figure is a code sequence composed of binary values of a and -a, where a is a positive real number, and the signal shape indicates a rectangular wave. The signal generation units 131, 132, 133, 134, 135, and 136 generate an audio signal composed of a pseudo random orthogonal code in such a code sequence. Each audio signal generated by the signal generators 131, 132, 133, 134, 135, 136 has a predetermined period and is composed of pseudo-random orthogonal codes that are pseudo-random and orthogonal to each other. Each audio signal is generated using a code or the like. The rectangular wave audio signal as shown in FIG. 3 includes a plurality of frequency components for causing the speaker to generate audio in the audible range, and is output to each speaker by the audio output unit 11 and is based on the output audio signal. The speaker produces sound.

FIG. 4 is a characteristic diagram showing the nature of the audio signal generated by the signal generators 131, 132, 133, 134, 135, 136. Let time be t, and let the signal strength of each audio signal at time t be f _n (t). However, n is a natural number and n = 1,. At this time, the autocorrelation g _n (τ) of the audio signal is defined by the following equation (1), where τ is the delay time.

L included in the equation (1) is an arbitrary integration period having a time dimension. FIG. 4A is a characteristic diagram showing the relationship between autocorrelation g _n (τ) and τ. Since the audio signal is a pseudo-random code sequence, the value of autocorrelation is almost zero when τ ≠ 0. When τ = 0, the square sum of the audio signal is obtained, so the autocorrelation value is a positive peak value. Since the pseudo-random orthogonal code has a predetermined period, when the period is X, a peak value of autocorrelation is obtained at τ = kX (k is an integer). Further, the m m = 1, ..., a is a natural number of 6, defines the cross-correlation g _nm of the speech signal is n ≠ m and (tau) by the following equation (2).

FIG. 4B is a characteristic diagram showing the relationship between the cross-correlation g _nm (τ) and τ. Since the audio signals are code sequences orthogonal to each other, the cross-correlation g _nm (τ) of the audio signals is a value close to 0 regardless of the value of τ. The signal generators 131, 132, 133, 134, 135, 136 have a sufficiently long period, the absolute value of the side lobe, which is the autocorrelation value when τ ≠ 0, and the absolute value of the cross-correlation value. A speech signal is generated using a pseudo-random orthogonal code whose value is sufficiently small.

  The level correction units 13 a, 13 b, 13 c, 13 d, 13 e, and 13 f have different amplification factors for the audio signals generated by the signal generation units 131, 132, 133, 134, 135, and 136 according to the control of the control unit 12. It is configured to amplify at. In this way, the level correction units 13a, 13b, 13c, 13d, 13e, and 13f function as amplification means according to the present invention. The amplification factor at which each level correction unit amplifies the audio signal is set in advance by the control unit 12 to a fixed value or a value corresponding to the situation where the sound field characteristic measurement system is installed. The level correction units 13a, 13b, 13c, 13d, 13e, and 13f are audio output units for the respective signal lines of the L channel, C channel, R channel, Ls channel, Rs channel, and SW channel. 11 is input.

  The microphone M is configured to collect sound in which sounds generated by the speakers L, C, R, Ls, Rs, and SW overlap and generate an input sound signal based on the collected sound. The microphone input unit 15 receives an input audio signal generated by the microphone M, appropriately amplifies the received input audio signal, performs AD conversion of the input audio signal as necessary, and sends the input audio signal to the sound field measurement unit 14. It has a configuration having an input function.

  FIG. 5 is a block diagram showing an internal functional configuration of the sound field measurement unit 14. The sound field measurement unit 14 includes a distribution unit 147 connected to the microphone input unit 15, and the distribution unit 147 is configured to receive an input audio signal from the microphone input unit 15. The distribution unit 147 is connected to the signal lines of the L channel, C channel, R channel, Ls channel, Rs channel, and SW channel, and distributes the same input audio signal input from the microphone input unit 15 to the signal lines of each channel. It is the composition to do. Correlation calculators 141, 142, and 143 that perform correlation calculation between the input audio signal and the audio signal corresponding to each channel are applied to the signal lines of the L channel, C channel, R channel, Ls channel, Rs channel, and SW channel. 144, 145, 146 are connected. Level correction units 14a, 14b, 14c, 14d, 14e, and 14f that amplify the output value of the correlation calculation are connected to the correlation calculation units 141, 142, 143, 144, 145, and 146, respectively. The level correction units 13a, 13b, 13c, 13d, 13e, and 13f are a frequency characteristic calculation unit (frequency characteristic calculation unit) 148 that obtains a frequency characteristic of the sound field based on an output value of the correlation calculation, and an output value of the correlation calculation. A relative delay time calculation unit 149 that calculates the relative delay time of the sound that reaches the microphone M from each speaker based on the above is connected.

  The correlation calculation units 141, 142, 143, 144, 145, and 146 have a memory for storing the audio signal and the input audio signal of each channel generated by the signal generation units 131, 132, 133, 134, 135, and 136. Thus, the correlation calculation between the input audio signal after the predetermined elapsed time and the audio signal of each channel is performed while changing the elapsed time. The input audio signal is a signal in which the audio signals based on the audio from each speaker are overlapped. As a result of performing the correlation operation with the audio signal of each channel generated by the measurement signal generating unit 13 on each channel, FIG. Due to the orthogonality between the audio signals shown in 4 (b), the component corresponding to the correlation calculation with the audio signals of different channels included in the output value of the correlation calculation becomes almost zero regardless of the elapsed time. Therefore, the output value of the correlation calculation is almost occupied by the component corresponding to the autocorrelation of the audio signal of each channel. In addition, due to the pseudo-randomness of the audio signal shown in FIG. 4A, the component corresponding to the autocorrelation is also almost zero with respect to most elapsed time, and is caused by the channel audio after the channel audio signal is generated. The output value of the correlation calculation becomes a peak value with respect to the elapsed time that is equal to the delay time until the input audio signal component is input to the sound field measurement unit 14.

  The correlation calculation units 141, 142, 143, 144, 145, and 146 input the output values of the correlation calculation performed to the level correction units 14a, 14b, 14c, 14d, 14e, and 14f. The level correction units 14 a, 14 b, 14 c, 14 d, 14 e, and 14 f are each channel when the level correction units 13 a, 13 b, 13 c, 13 d, 13 e, and 13 f amplify the audio signal of each channel according to the control of the control unit 12. The output value of the correlation calculation of each channel is amplified with an amplification factor that is inversely proportional to the amplification factor that differs between the channels. The level correction units 14 a, 14 b, 14 c, 14 d, 14 e, and 14 f input the amplified output value of the correlation calculation of each channel to the frequency characteristic calculation unit 148 and the relative delay time calculation unit 149.

  The relative delay time calculation unit 149 obtains an elapsed time value at which the peak of the correlation calculation output value is obtained in each channel, and obtains a relative value between the channels at the elapsed time at which the peak of the correlation calculation output value is obtained. It has become. This relative value corresponds to the relative delay time between the channels until the sound of each channel reaches the microphone M. The relative delay time calculation unit 149 is configured to input an elapsed time value at which the peak of the output value of the correlation calculation is obtained in each channel to the frequency characteristic calculation unit 148.

  The frequency characteristic calculation unit 148 is configured to Fourier-transform a function of the correlation calculation output value and elapsed time in each channel. At this time, the frequency characteristic calculation unit 148 performs the Fourier transform of the function using the elapsed time value input from the relative delay time calculation unit 149 for each channel as a trigger. When any frequency component included in the input audio signal is attenuated as compared to the audio signal generated by the measurement signal generation unit 13, the attenuation becomes clear from the result of Fourier transform.

  Next, the sound field characteristic measuring method of the present invention executed by the sound field characteristic measuring system having the above configuration will be described. First, the microphone M is placed at a viewing position where the user views audio, such as the position of the sofa when the acoustic system is installed in the home, or the position of the driver's seat when the acoustic system is installed in the automobile. Install it. When the microphone M is installed at the viewing position and the user receives an instruction to measure the sound field characteristic by operating the operation means (not shown) provided in the amplification device 1 or the like, the sound field characteristic measurement system Execute the process of measuring the field characteristics. FIG. 6 is a flowchart showing a procedure of processing performed by the sound field characteristic measurement system of the present invention.

  The signal generators 131, 132, 133, 134, 135, and 136 generate audio signals composed of pseudo random orthogonal codes corresponding to the respective channels (S1). Next, the level correction units 13a, 13b, 13c, 13d, 13e, and 13f amplify the audio signal of each channel for each channel with a different amplification factor between the channels according to the control of the control unit 12 (S2). For example, when an acoustic system is installed in an automobile and a microphone M is installed on the front seat, the intensity of the sound generated by the rear speakers Ls and Rs and reaching the microphone M is affected by the shielding of the seat and the like. Therefore, it becomes smaller than the front speakers L, C, R. Therefore, in this case, by making the audio signals of the Ls channel and the Rs channel larger than the audio signals of the other channels, the microphone M collects audio from the rear speakers Ls and Rs with good sensitivity. Will be able to. The amplification factor for each channel in step S2 is set in advance by the control unit 12, and processing for setting the amplification factor according to the installation state of the sound field characteristic measurement system may be performed by a user operation. Alternatively, the measurement of collecting the sound from each speaker with the microphone M in advance may be performed, and the process of setting the amplification factor according to the result of the preliminary measurement may be performed.

  The level correction units 13a, 13b, 13c, 13d, 13e, and 13f input the amplified audio signals of the respective channels to the audio output unit 11, and the audio output unit 11 appropriately amplifies the audio signals of the respective channels. It outputs to the speaker corresponding to each channel (S3). The speakers L, C, R, Ls, Rs, and SW generate sound based on the sound signal of each channel output from the sound output unit 11 (S4). The microphone M collects sounds in which the sounds generated by the speakers L, C, R, Ls, Rs, and SW are overlapped, and generates an input sound signal based on the collected sounds (S5).

  The input audio signal generated by the microphone M is ideally a superposition of the audio signals of the respective channels input to the audio output unit 11 by the level correction units 13a, 13b, 13c, 13d, 13e, and 13f. However, depending on the characteristics of the amplification function of the sound output unit 11, the characteristics of the speakers L, C, R, Ls, Rs, SW, the sound propagation characteristics in the sound field space where the sound measurement system is installed, etc. The signal changes compared to the original audio signal. Further, due to the relative delay time until the sound from each speaker reaches the microphone M, the sound signals of the respective channels are overlapped with a time shift. Furthermore, an audio signal resulting from multipath audio that reaches the microphone M after being reflected at least once by a wall or the like in the sound field space is also included in the input audio signal. The input audio signal generated by the microphone M is obtained by convolving these acoustic system and sound field space characteristics.

  The microphone M inputs the generated input audio signal to the microphone input unit 15. The microphone input unit 15 inputs the input audio signal to the sound field measurement unit 14. In the sound field measurement unit 14, the distribution unit 147 is the same. The input audio signal is distributed to each channel (S6). The correlation calculation units 141, 142, 143, 144, 145, and 146 execute a correlation calculation between the portion of the input audio signal after a predetermined elapsed time and the audio signal of each channel generated by the measurement signal generation unit 13 (S7). ).

FIG. 7 is a characteristic diagram for explaining the contents of the correlation calculation in step S7. Here, it is assumed that the start of measurement of the sound field characteristic is t = 0 and the input sound signal is F (t). FIG. 7A shows an example of the input audio signal F (t). Since a plurality of types of rectangular waves overlap, the waveform is distorted. FIG. 7B shows an example of the audio signal f _n (t) of each channel. Let T be the elapsed time from the start of measurement. Each correlation calculation unit calculates an output value G (T) of the correlation calculation, for example, according to the following equation (3).

  D included in the equation (3) is an arbitrary integration period. T and D are shown in FIG. As described above, due to the orthogonality between the audio signals composed of pseudo-random orthogonal codes, the correlation calculation between the components of the different channels included in the input audio signal and the audio signal is the correlation calculation output value G ( T) is almost zero. Also, due to the pseudo-randomness of the audio signal composed of pseudo-random orthogonal codes, the delay time from when the audio signal of the channel is generated until the component of the input audio signal resulting from the audio of the channel is input to the sound field measuring unit 14 For the same elapsed time T, the output value G (T) of the correlation calculation is a peak value. Note that equation (3) is an example of a specific equation for correlation calculation, and each correlation calculation unit is different from equation (3) in that the range of integration is different from equation (3). A configuration may be used in which the correlation calculation is performed based on the above.

  FIG. 8 is a characteristic diagram showing an example of an output value G (T) of correlation calculation in each channel. G (T) peak values are obtained for a plurality of T in each channel, and the T value at which the first peak value is obtained among the plurality of peak values is the delay time in each channel. The second and subsequent peak values are peak values resulting from multipath.

  The correlation calculation units 141, 142, 143, 144, 145, and 146 input the correlation calculation output values to the level correction units 14a, 14b, 14c, 14d, 14e, and 14f, and the level correction units 14a, 14b, 14c, and 14d. , 14e, and 14f are amplification factors that are inversely proportional to the amplification factors that differ between the channels when the level correction units 13a, 13b, 13c, 13d, 13e, and 13f amplify the audio signals of the respective channels according to the control of the control unit 12. Thus, the output value of the correlation calculation of each channel is amplified (S8). The level correction units 14a, 14b, 14c, 14d, 14e, and 14f input the output values of the correlation calculation after amplification to the frequency characteristic calculation unit 148 and the relative delay time calculation unit 149, and the relative delay time calculation unit 149 A relative delay time calculation process is performed (S9).

FIG. 9 is a flowchart showing the procedure of the subroutine of the relative delay time calculation process in step S9. The relative delay time calculation unit 149 obtains a channel delay time that is an elapsed time T at which the first peak of the correlation calculation output value G (T) is obtained in each channel (S91). The channel delay time in each channel is T _L , T _C , T _R , T _Ls , T _Rs , and T _{SW shown} in FIG. Next, the relative delay time calculation unit 149 selects the minimum channel delay time among the plurality of channel delay times (S92). In the example shown in FIG. 8, the minimum channel delay time is T _Rs . Next, the relative delay time calculation unit 149 obtains the relative delay time between channels by subtracting the minimum channel delay time from the other channel delay times (S93). In the example shown in FIG. 8, the relative delay times in the L channel, C channel, R channel, Ls channel, Rs channel, and SW channel are T _L −T _Rs , T _C −T _Rs , and T _R −T. _Rs , T _Ls −T _Rs , 0, T _SW −T _Rs . This relative delay time is the delay time of the sound that reaches the viewing position from each speaker. The relative delay time calculation unit 149 ends the relative delay time calculation processing subroutine, and returns the processing to the main routine.

  The relative delay time calculation unit 149 inputs the calculated channel delay time in each channel to the frequency characteristic calculation unit 148, and the frequency characteristic calculation unit 148 outputs the correlation calculation output value from the input channel delay time in each channel. A function of the output value G (T) of the correlation calculation in each channel and the elapsed time T within the range up to the value of the elapsed time at which the absolute value of the peak value of G (T) is equal to or greater than a predetermined value is Fourier transformed. Thus, the frequency characteristic in each channel is calculated (S10). The range in which the correlation calculation output value G (T) is Fourier-transformed is a range in which the absolute value of the peak value of the correlation calculation output value G (T) is equal to or greater than a predetermined value with sufficient intensity for Fourier transformation. Each channel may be different from each other. In particular, in the SW channel, Fourier transform is performed within a range where the low-frequency characteristics can be calculated. The sound field characteristic measurement system of the present invention ends the process of measuring the sound field characteristic.

  The relative delay time in each channel calculated by the relative delay time calculation unit 149 and the frequency characteristic in each channel calculated by the frequency characteristic calculation unit 148 are stored in the sound field measurement unit 14 or the control unit 12. The relative delay time in each channel is used as data for correcting a time lag until sound reaches each viewing position from each speaker. The frequency characteristics in each channel indicate which frequency component is easily attenuated in the sound field space, and are used as data for correcting the frequency of the sound using an equalizer or the like.

  As described above in detail, in the present invention, for each channel corresponding to a plurality of speakers, an audio signal composed of a pseudo-random orthogonal code corresponding to the channel is generated, and each speaker is generated based on the audio signal of each channel. Collects voices that overlap with each other, generates an input voice signal based on the collected voices, calculates the correlation between the input voice signal after a predetermined elapsed time and the original voice signal in each channel, and performs correlation The relative delay time in each channel is obtained from the elapsed time at which the peak value of the calculation is obtained. Therefore, in addition to the microphone that collects sound at the viewing position, a microphone for generating a trigger signal that has been conventionally required is unnecessary. In addition, by using the orthogonality and pseudorandomness of the audio signal consisting of pseudo-random orthogonal codes generated in each channel, the relative delay time and frequency characteristics of the sound field consisting of the audio generated by multiple speakers can be reduced to a single. Since it is possible to perform measurement simultaneously using a microphone, it is possible to reduce labor and time required for measuring a sound field as compared with a conventional method in which sound field measurement is repeated for each channel.

  Further, in the present invention, when calculating the frequency characteristics in each channel, the Fourier transform is performed in the range where the absolute value of the peak value of the output value of the correlation calculation is not less than a predetermined value having a sufficient intensity for the Fourier transform. Thus, the frequency characteristic of the sound field can be calculated efficiently. In the present invention, when the measurement signal generator 13 generates an audio signal, the audio signal is amplified with a different amplification factor between channels, and the sound field measurement unit 14 determines the input signal and the audio signal of each channel. Is amplified with an amplification factor that is inversely proportional to the amplification factor in the measurement signal generator 13, so that sound of a channel that tends to be attenuated in the sound field space is collected with good sensitivity. It is possible to measure field characteristics.

  In the present embodiment, the measurement signal generation unit 13 and the sound field measurement unit 14 are configured to execute a necessary process by combining a plurality of hardware. However, the present invention is not limited to this. It may be configured by a general-purpose processor and a ROM that stores a program, and may execute a necessary process using software.

  In this embodiment, the sound field characteristic measurement system of the present invention is configured to be incorporated in an acoustic system including six speakers. However, the present invention is not limited to this, and two or more speakers are used. The present invention can be configured with any sound system provided.

(Embodiment 2)
FIG. 10 is a block diagram showing the configuration of the sound field characteristic measurement system according to the second embodiment of the present invention. The sound field characteristic measurement system according to Embodiment 2 reads a recording medium D on which data for generating a plurality of channels of audio signals to be output to the speakers L, C, R, Ls, Rs, and SW is recorded. An audio player 4 is provided. As a recording medium D capable of recording such data for multi-channel audio signals, SACD (Super Audio CD), DVD-audio, or the like can be used. The amplifying device 3 according to the present embodiment includes an amplifying unit 31 connected to the audio player 4 through respective signal lines of L channel, C channel, R channel, Ls channel, Rs channel, and SW channel. Are connected to the audio output unit 11 by signal lines of respective channels.

  The audio player 4 can read, as the recording medium D, the recording medium D that records data for generating a plurality of audio signals modulated by pseudo random orthogonal codes corresponding to each channel. Based on this, a plurality of audio signals modulated with pseudo-random orthogonal codes corresponding to each channel are generated, and the generated audio signals of each channel are input to the amplifying unit 31. The amplifying unit 31 receives the audio signal of each channel from the audio player 4, amplifies the audio signal of each channel at a different amplification factor between channels under the control of the control unit 12, and sends the amplified audio signal to the audio output unit 11. It is configured to input. Thus, the amplifying unit 31 functions as an audio signal receiving unit and an amplifying unit according to the present invention. The sound field measurement unit 14 stores a sound signal of each channel in advance, and is configured to perform a correlation calculation between the stored sound signal and the input sound signal. Note that the audio signal of each channel input to the amplifier 3 by the audio player 4 is also input to the sound field measurement unit 14, and the sound field measurement unit 14 performs correlation calculation using the input audio signal. Also good. The configurations and functions of the other parts of the sound field characteristic measurement system are the same as those in the first embodiment, and the corresponding parts are denoted by the same reference numerals and description thereof is omitted.

  The procedure of the process performed by the sound field characteristic measurement system according to the present embodiment is almost the same as that of the first embodiment shown in FIG. The audio player 4 reads data from the recording medium D, and generates a plurality of audio signals modulated with pseudo random orthogonal codes corresponding to each channel based on the read data (S1). The audio player 4 inputs the generated audio signal of each channel to the amplifying unit 31, and the amplifying unit 31 amplifies the audio signal input from the audio player 4 for each channel at a different amplification factor between channels (S2). . The amplification unit 31 inputs the audio signal of each channel to the audio output unit 11, and the audio output unit 11 appropriately amplifies the audio signal of each channel and outputs the amplified signal to the speaker corresponding to each channel (S3). The contents of the processing after step S4 are the same as those in the first embodiment, and the description thereof is omitted.

  As described in detail above, in the present embodiment, the audio player 4 reads the recording medium D for recording data for generating a plurality of audio signals modulated by the pseudo random orthogonal code corresponding to each channel, and each channel The audio player 4 is caused to function as a signal generation unit according to the present invention that generates an audio signal modulated with a pseudo-random orthogonal code corresponding to. As a result, the sound field characteristic measurement system does not need to include the signal generation means according to the present invention separately from the audio player 4, so that the configuration of the amplification device 3 and the sound field characteristic measurement system can be simplified and the cost can be reduced. It becomes possible.

  In the present embodiment, the audio player 4 is connected to the outside of the amplifying device 3, but the sound field characteristic measuring system of the present invention includes the audio player 4 built in the amplifying device 3. It may be a form.

(Embodiment 3)
FIG. 11 is a block diagram showing a configuration of a sound field characteristic measuring system according to the third embodiment of the present invention. The sound field characteristic measurement system according to Embodiment 3 includes a sound field characteristic measurement device 6 separately from the audio player 2 and the amplification device 5. The sound field characteristic measuring apparatus 6 includes therein a measurement signal generating unit 63 that is a signal generating unit according to the present invention and a sound field measuring unit 64 that is a sound field measuring unit according to the present invention. The measurement signal generating unit 63 is configured to be connectable to the audio output unit 11 of the amplifying device 5 through respective signal lines of L channel, C channel, R channel, Ls channel, Rs channel, and SW channel. The sound field characteristic measuring apparatus 6 further includes a microphone input unit 15 to which a microphone M is connected. The sound field characteristic measuring device 6 is not connected to the amplifying device 5 when an acoustic system including the amplifying device 5 is normally used, and the sound field characteristic measuring device 6 is connected to the amplifying device 5 when measuring the sound field characteristics with the acoustic system. It is connected and constitutes the sound field characteristic measuring system of the present invention.

  In the sound field characteristic measurement system according to the present embodiment, the measurement signal generator 63 generates an audio signal of each channel and inputs it to the amplifying device 5, and the speakers L, C, R, Ls, Rs, and SW are generated. The microphone M collects the sound, and the sound field measurement unit 64 calculates the relative delay time and the frequency characteristic of each channel, thereby performing the sound field characteristic measurement process in the same processing procedure as in the first embodiment. By adopting such a configuration, it is possible to realize a sound field characteristic measuring system by connecting the sound field characteristic measuring device 6 to the amplifying device 5 only when necessary, and the characteristic of the sound field is normally measured. By not including the function in the amplification device, the acoustic system can be configured more simply.

(Embodiment 4)
FIG. 12 is a block diagram showing the configuration of the sound field characteristic measurement system according to the fourth embodiment of the present invention. The sound field characteristic measurement system according to Embodiment 4 reads a recording medium D on which data for generating a plurality of channels of audio signals to be output to the speakers L, C, R, Ls, Rs, and SW is recorded. The audio player 4 is connected to the amplifying device 7. Furthermore, the sound field characteristic measuring system includes a sound field characteristic measuring device 8. The sound field characteristic measuring apparatus 8 includes a sound field measuring unit 84 that is a sound field measuring unit according to the present invention, and a microphone M is connected to the sound field measuring unit 84 via a microphone amplifier 81. The macrophone M generates an input audio signal based on the collected sound, and the microphone amplifier 81 is configured to amplify the input audio signal generated by the macrophone M and input it to the sound field measurement unit 84. The sound field characteristic measurement system according to the present embodiment connects the microphone M installed at the viewing position to the sound field characteristic measurement device 8 via the microphone amplifier 81 when measuring the sound field characteristic with the acoustic system. The audio player 4 is made to read the recording medium D which records the data for producing | generating the several audio | voice signal modulated with the pseudo random orthogonal code corresponding to each channel.

  In the sound field characteristic measurement system according to the present embodiment, the microphone M generates an input sound signal based on the sound generated by overlapping the sounds generated by the speakers, and the microphone amplifier 81 sends the input sound signal to the sound field measurement unit 84. Then, the sound field measurement unit 84 calculates the relative delay time and frequency characteristic of each channel, thereby performing the sound field characteristic measurement process in the same processing procedure as in the second embodiment. By adopting such a configuration, the sound field can be obtained by bringing the recording medium D, the microphone M, the microphone amplifier 81, and the sound field characteristic measuring device 8 to an acoustic system that does not have the function of measuring the sound field characteristic. Therefore, it is possible to construct a sound field characteristic measurement system and measure the sound field characteristic more easily.

It is a block diagram which shows the structure of the sound field characteristic measuring system of this invention which concerns on Embodiment 1. FIG. It is a block diagram which shows the function structure inside a measurement signal generation part. It is a characteristic view which shows the example of an audio | voice signal. It is a characteristic view which shows the property of the audio signal which a signal generation part produces | generates. It is a block diagram which shows the function structure inside a sound field measurement part. It is a flowchart which shows the procedure of the process which the sound field characteristic measuring system of this invention performs. It is a characteristic view explaining the content of the correlation calculation in step S7. It is a characteristic view which shows the example of the output value G (T) of the correlation calculation in each channel. It is a flowchart which shows the procedure of the process of the subroutine of the relative delay time calculation process in step S9. It is a block diagram which shows the structure of the sound field characteristic measuring system of this invention which concerns on Embodiment 2. FIG. It is a block diagram which shows the structure of the sound field characteristic measuring system of this invention which concerns on Embodiment 3. FIG. It is a block diagram which shows the structure of the sound field characteristic measuring system of this invention which concerns on Embodiment 4. FIG.

Explanation of symbols

1, 3, 5, 7 Amplifying device 11 Audio output unit 13, 63 Measurement signal generation unit 131, 132, 133, 134, 135, 136 Signal generation unit 13a, 13b, 13c, 13d, 13e, 13f Level correction unit (amplification means)
14, 64, 84 Sound field measuring unit (sound field measuring means)
148 Frequency characteristic calculation unit (frequency characteristic calculation means)
149 Relative delay time calculation unit 15 Microphone input unit (input audio signal receiving means)
2,4 Audio player 31 Amplification part (amplification means)
6,8 Sound field characteristic measuring device L, C, R, Ls, Rs, SW Speaker M Microphone D Recording medium

Claims (10)

In a method of measuring characteristics of a sound field composed of sound generated by a plurality of speakers using a microphone that collects the sound,
Generate a plurality of audio signals modulated with pseudo-random orthogonal codes corresponding to each of a plurality of speakers among a plurality of pseudo-random orthogonal codes that are pseudo-random and orthogonal to each other,
Output audio signals corresponding to each generated speaker to each speaker,
The microphone collects sound in which sound generated by a plurality of speakers is overlapped based on the output sound signal,
Generating an input audio signal based on the sound collected by the microphone;
Performing a correlation operation between a portion of the generated input audio signal after a predetermined elapsed time and an audio signal modulated with a pseudo-random orthogonal code corresponding to each speaker while changing the elapsed time,
Obtain the value of the elapsed time at which the peak of the output value of the correlation calculation corresponding to each speaker is obtained,
A sound field characteristic measuring method, comprising: obtaining a relative delay time of sound generated by a plurality of speakers based on a relative difference between the speakers corresponding to each speaker. A plurality of speakers that generate sound based on the sound signal, a sound output unit that outputs a sound signal corresponding to each speaker to each speaker, and a plurality of sound signals that the sound output unit outputs to the plurality of speakers Based on the input sound signal generated by the microphone, the microphone for generating the input sound signal based on the collected sound, the signal generating means for generating the sound generated by the plurality of speakers, In a sound field characteristic measuring system comprising: a sound field measuring means for measuring characteristics of a sound field composed of sound generated by a plurality of speakers;
The signal generation means is configured to generate a plurality of audio signals modulated with a pseudo random orthogonal code corresponding to each of a plurality of speakers among a plurality of pseudo random orthogonal codes which are pseudo-random and orthogonal code sequences. And
The microphone is configured to generate an input sound signal based on a sound obtained by overlapping sounds generated by a plurality of speakers,
The sound field measuring means is
Correlation calculation means for performing a correlation calculation between a portion after a predetermined elapsed time of the input audio signal generated by the microphone and an audio signal modulated with a pseudo-random orthogonal code corresponding to each speaker while changing the elapsed time;
Means for obtaining a value of an elapsed time at which a peak of the output value of the correlation calculation corresponding to each speaker is obtained;
A sound field characteristic comprising: a means for obtaining a relative delay time of sound generated by a plurality of speakers based on a relative difference between the speakers corresponding to each speaker obtained by the means; Measuring system. The signal generating means is configured to generate an audio signal for causing a speaker to generate audio including a plurality of frequency components in an audible range,
The sound field measuring means is
The sound according to claim 2, further comprising frequency characteristic calculation means for obtaining a frequency characteristic of the sound field by performing a Fourier transform on a function of the output value of the correlation calculation corresponding to each speaker with respect to an elapsed time. Field characteristic measurement system.   The frequency characteristic calculating means is configured to Fourier-transform the function including discrete peaks of the output value within an elapsed time range in which the absolute value of the peak value is a predetermined value or more. The sound field characteristic measurement system according to claim 2 or 3, The audio signal corresponding to each speaker generated by the signal generation unit further includes an amplification unit that amplifies the audio signal with different amplification factors between the speakers according to a predetermined setting,
The correlation calculation means includes
The means for amplifying the output value of the correlation operation corresponding to each speaker at an amplification factor that is inversely proportional to the amplification factor that differs between the speakers when the amplification means amplifies the audio signal. 4. The sound field characteristic measurement system according to any one of 4. The signal generating means includes
An audio player that reads data from a recording medium that records data for generating an audio signal corresponding to each speaker, and generates an audio signal based on the read data;
When data is read from a recording medium for recording data for generating a plurality of audio signals modulated with pseudo random orthogonal codes corresponding to each of the plurality of speakers, the pseudo corresponding to each speaker is read based on the read data. The sound field characteristic measuring system according to any one of claims 2 to 5, wherein the sound signal is modulated with a random orthogonal code. An audio output means for outputting an audio signal to each of a plurality of external speakers that generate audio based on the audio signal; a signal generating means for generating a plurality of audio signals for output to the plurality of speakers; Input sound signal receiving means for receiving an input sound signal generated based on sound collected by an external microphone that picks up sound generated by the speaker, and based on the input sound signal received by the input sound signal receiving means Amplifying apparatus comprising: sound field measuring means for measuring characteristics of a sound field composed of sound generated by the plurality of speakers;
The signal generating means generates a plurality of audio signals modulated with a pseudo random orthogonal code corresponding to each of a plurality of external speakers among a plurality of pseudo random orthogonal codes which are pseudo random and orthogonal code sequences. Configured
The input sound signal receiving means is configured to receive an input sound signal generated by an external microphone based on sound in which sound generated by the plurality of speakers overlaps,
The sound field measuring means is
While changing the elapsed time, the correlation calculation between the portion of the input audio signal received by the input audio signal receiving means after a predetermined elapsed time and the audio signal modulated by the pseudo random orthogonal code corresponding to each external speaker Correlation calculating means to perform;
Means for obtaining a value of an elapsed time at which a peak of the output value of the correlation calculation corresponding to each external speaker is obtained;
Means for determining a relative delay time of sound generated by a plurality of external speakers based on a relative difference between the speakers in the value corresponding to each external speaker determined by the means. Amplifying device. The signal generating means includes
An audio player that reads data from a recording medium that records data for generating audio signals corresponding to each external speaker, and generates an audio signal based on the read data;
When data is read from a recording medium that records data for generating a plurality of audio signals modulated with pseudo-random orthogonal codes corresponding to each of the plurality of external speakers, each external speaker is based on the read data. The amplifying apparatus according to claim 7, wherein the amplifying apparatus is configured to generate an audio signal modulated with a pseudo-random orthogonal code corresponding to. A sound signal receiving means for receiving a plurality of sound signals for outputting to each of a plurality of external speakers that generate sound based on the sound signal, and a sound signal received by the sound signal receiving means by appropriately adjusting the sound signals Audio output means for outputting to each external speaker; input audio signal receiving means for receiving an input audio signal generated based on the sound collected by an external microphone that collects the sound generated by the plurality of speakers; and In an amplifying apparatus comprising: a sound field measuring unit that measures characteristics of a sound field composed of sounds generated by the plurality of speakers based on an input sound signal received by the input sound signal receiving unit;
The audio signal receiving unit receives each of a plurality of audio signals modulated by pseudo random orthogonal codes corresponding to each of a plurality of speakers among a plurality of pseudo random orthogonal codes that are pseudo-random and orthogonal code sequences. Configured
The input sound signal receiving means is configured to receive an input sound signal generated by an external microphone based on sound in which sound generated by the plurality of speakers overlaps,
The sound field measuring means is
Correlation between a portion of the input audio signal received by the input audio signal receiving means after a predetermined elapsed time and an audio signal modulated with a pseudo-random orthogonal code corresponding to each speaker while changing the elapsed time Computing means;
Means for obtaining a value of an elapsed time at which a peak of the output value of the correlation calculation corresponding to each external speaker is obtained;
Means for determining a relative delay time of sound generated by a plurality of external speakers based on a relative difference between the speakers in the value corresponding to each external speaker determined by the means. Amplifying device. In an apparatus for measuring the characteristics of a sound field composed of sound generated by a plurality of external speakers,
Each of the plurality of speakers is generated based on a plurality of audio signals modulated with a pseudo-random orthogonal code corresponding to each of the plurality of pseudo-random orthogonal codes which are pseudo-random and orthogonal code sequences. Means for receiving an input voice signal generated by an external microphone that collects voices that overlap with each other;
Correlation calculation means for performing correlation calculation between a portion of the input audio signal received by the means after a predetermined elapsed time and the audio signal modulated with a pseudo random orthogonal code corresponding to each external speaker while changing the elapsed time. When,
Means for obtaining a value of an elapsed time at which a peak of the output value of the correlation calculation corresponding to each external speaker is obtained;
Means for determining a relative delay time of sound generated by a plurality of external speakers based on a relative difference between the speakers in the value corresponding to each external speaker determined by the means. Sound field characteristic measuring device.

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