JP5118517B2 - Sound field space control system - Google Patents

Description

  The present invention relates to a sound field space control system that controls sound generated from a sound source and propagating through a sound field space.

  A wireless microphone carried by a performer or singer and transmitting performance sound or singing sound as an audio signal, a plurality of audio signal receiving devices receiving audio signals transmitted from the wireless microphone, and the audio signal receiving device receiving A position measuring means for determining the position of the wireless microphone that is the transmission source of the audio signal based on the received electric field strength of the audio signal, and a plurality of speakers having a sound image position at the position determined by the position positioning means There is a sound field control system formed from a sound image localization control device that synthesizes signals for driving the speakers from the output signals of the audio signal receiving devices.

The control procedure in this sound field control system will be described as follows. When a musical instrument player or singer performs a musical instrument or sings a song while moving on the stage, the performance sound or singing sound is transmitted as an audio signal from the wireless microphone, and the audio signal is received by the audio signal receiving device. The The position positioning means measures the location of the wireless microphone based on the received electric field strength of the audio signal received by the audio signal receiving device. The sound image localization control device adjusts the level of the drive signal supplied to each speaker so that the position of the sound image of the sound output from the plurality of speakers is localized at the location of the wireless microphone.
JP 2006-324999 A

  The sound field control system disclosed in Patent Document 1 can identify a position where a performance sound or singing sound is generated, and can obtain a speaker reproduction sound localized in the sound image at that position, thereby forming a sound field rich in presence. can do. However, this sound field control system cannot adjust a frequency characteristic of a predetermined frequency band of a sound generated from a musical instrument player or singer to create a sound having a desired frequency characteristic. It is not possible to let the audience present at a position away from the listener hear the sound having the frequency characteristics desired by the audience. In addition, this sound field control system cannot adjust the reverberation characteristics of sounds generated by musical instrument players and singers to create a sound with the desired reverberation, and is located at a position away from musical instrument players and singers. An existing audience cannot hear a sound with the desired reverberation.

  The object of the present invention is to adjust the frequency characteristics of a predetermined frequency band of the sound generated from the sound source to create a sound having a desired frequency characteristic. The object is to provide a sound field space control system that can be heard individually. Another object of the present invention is to adjust the reverberation characteristics of the sound generated from the sound source to create a sound having a desired reverberation, and to let each audience individually hear the sound having the reverberation desired by the audience. It is to provide a sound field space control system capable of

  A sound field space control system according to the present invention for solving the above-described problem is arranged in a first sound wave that is disposed in a sound field space at a predetermined distance from a sound source that generates the first sound wave and propagates from the sound source to the sound field space. the first to the n-th wave generator that generates the interfering second waves into the sound field space, the sound source and is disposed between their wave generator, detects a composite wave of the first wave and the second acoustic wave The synthesized sound wave detection sensor that outputs the detected synthesized sound wave as the first signal and the first sound wave and the second sound wave are arranged with a predetermined distance from the synthesized sound wave detection sensor with the first to nth sound wave generators interposed therebetween. The first to n-th interference sound wave detection sensors that detect the interference sound waves generated by the interference with the sound waves and output the detected interference sound waves as the second signal have a correspondence relationship with the first to n-th sound wave generators. From these sound wave generators to synthetic sound wave detection sensors The first to n-th pseudo feedback signal generation filters that generate pseudo feedback signals that estimate the second sound wave and the first to n-th pseudo feedback signal generation filters have a corresponding relationship. 1st to n-th third signal output devices for receiving a pseudo feedback signal from the pseudo feedback signal generation filter and outputting a third signal obtained by removing the pseudo feedback signal from the first signal while receiving one signal; A target signal generator for receiving a third signal from first to nth third signal output devices, adjusting a frequency characteristic of the third signal, and converting the third signal into a target signal having a desired frequency characteristic; , Having a corresponding relationship with the first to nth interference sound wave detection sensors, receiving the second signal from the interference sound wave detection sensors and receiving the target signal from the target signal generation device The first to nth error signal output devices for outputting an error signal obtained by removing the target signal from the second signal and the first to nth sound wave generators have a corresponding relationship, and the first to nth using 3 third signal received from the signal output device and a error signal received from the error signal output device of the first to n generates an interference signal as a second wave, first to the generated interference signal and first to nth interference signal generation devices that output to n sound wave generation devices.

  As an example of the sound field space control system according to the present invention, the target signal generation device includes a first digital filter that simulates a time-series transfer characteristic from the synthetic sound wave detection sensor to the interference sound wave detection sensor, and a third signal. And an equalizer for amplifying or attenuating the volume of an arbitrarily selected frequency band.

  As another example of the sound field space control system according to the present invention, the target signal generating device comprises a delay correction unit first wave to the interference wave detection sensor from the composite acoustic wave detection sensor to correct the time delay until the propagation, And an equalizer for amplifying or attenuating the volume of an arbitrarily selected frequency band of the third signal.

  As another example of the sound field space control system according to the present invention, the target signal generation device includes a reverb that adjusts the reverberation characteristic of the third signal.

  As another example of the sound field space control system according to the present invention, an interference signal generation device uses an adaptive digital filter for generating an interference signal and an adaptive digital filter using an error signal received from an error signal output device. And an adaptive control arithmetic unit to be updated.

  As another example of the sound field space control system according to the present invention, the interference signal generation device includes a second digital filter that simulates a time-series transfer characteristic from the sound wave generation device to the interference sound wave detection sensor, and the adaptive control calculation unit includes The adaptive digital filter is updated using the time-series transfer characteristics simulated by the second digital filter and the error signal received from the error signal output device.

  As another example of the sound field space control system according to the present invention, the sampling frequency in the sound field space control system is in the range of 3 kHz to 40 kHz.

  As another example of the sound field space control system according to the present invention, the number of interference sound wave detection sensors is the same as the number of sound wave generators or more than the number of sound wave generators.

  As another example of the sound field space control system according to the present invention, the synthetic sound wave detection sensor is disposed in the vicinity of the sound source, and the sound wave generator and the interference sound wave detection sensor are disposed in the vicinity of the audience who listens to the interference sound wave. .

  As another example of the sound field space control system according to the present invention, the sound field space is an internal space of a concert hall, a multipurpose hall, a live house, an opera house, a lecture room, or a listening room, and the first sound wave is Music or voice.

  According to the sound field space control system of the present invention, the target signal generation device converts the third signal into a target signal having a desired frequency characteristic, and the first to nth error signal output devices convert the second signal to the target signal. Are output from the third signal received from the first to n-th third signal output devices and the first to n-th error signal output devices. Since the interference signal that becomes the second sound wave is output using the received error signal, the second signal output from the first to n-th interference sound wave detection sensors can be approximated to the target signal, and the target signal is generated. The sound propagated to the position of the interference acoustic wave detection sensor by the apparatus can be arbitrarily and freely adjusted to a sound having a desired frequency characteristic.

  The sound field space control system outputs, to the interference signal generating device, the frequency band to be strengthened, the frequency band to be weakened, and the frequency band to be erased of the second signal as error signals, and the interference signal generating device outputs the error signal and the third signal. Is used to generate an interference signal that becomes the second sound wave, and various interference signals that interfere with the frequency band to be strengthened, weakened frequency band, and to be erased are transmitted to the sound wave generating device via the interference signal generating device. Can be output. Therefore, you can freely and freely select the frequency band you want to strengthen, the frequency band you want to weaken, the frequency band you want to erase from the sound propagating through the sound field space, by amplifying, attenuating, and silencing only the selected frequency band, The sound propagated to the position of the interference sound wave detection sensor can be changed to a sound having a desired frequency characteristic, and a desired sound can be made at the position of the interference sound wave detection sensor. This sound field space control system can let the audience located in the vicinity of the interfering sound wave detection sensor individually hear sounds having frequency characteristics desired by the audience.

  The sound field space control system arranges the first to nth sound wave generators, and propagates the second sound waves uniformly from the sound wave generators to the control target space in the sound field, thereby spreading the second sound wave into the control target space. The second sound wave can be reliably caused to interfere with one sound wave, and the sound propagated to the position of the interference sound wave detection sensor can be reliably changed to a sound having a desired frequency characteristic. The sound field space control system, an interference wave detection sensor of the first to n are arranged, interference waves spread control target space in the sound field that is detected in their interference wave detection sensor, the output from the interference wave detection sensor The second signal thus made can be approximated to the target signal as much as possible, and the sound propagated to the position of the interference sound wave detection sensor can be reliably changed to a sound having a desired frequency characteristic.

  The sound field space control system generates a third signal obtained by removing a pseudo feedback signal that can be estimated as a second signal from the first signal by the third signal output device, and uses the third signal as an interference signal generation device or a target signal generation device. Therefore, the third signal output to the interference signal generation device or the target signal generation device does not include a pseudo feedback signal that estimates the second sound wave reaching the synthetic sound wave detection sensor. Howling can be prevented. If the combined signal including the interference signal is output to the interference signal generation device as it is, an interference signal including a sound wave that amplifies, attenuates, and silences the interference signal is generated. In this system, a pseudo feedback signal is generated from the combined signal. Since the third signal excluding the signal is output to the interference signal generation device, it is possible to prevent the interference signal from including a sound wave that amplifies, attenuates, and silences the interference signal. Further, when an interference signal is included in the signal output to the target signal generation device, a combined signal of the first signal and the interference signal is output to the target signal generation device, and a frequency band to be amplified, attenuated, or silenced is selected. However, in this system, since the third signal obtained by removing the pseudo feedback signal from the synthesized signal is output to the target signal generation device, the frequency band that is desired to be amplified, attenuated, or silenced in the target signal generation device is ensured. Can be selected.

  In the sound field space control system in which the target signal generation device is formed of the first digital filter and the equalizer, the time series transfer characteristic from the synthesized sound wave detection sensor to the interference sound wave detection sensor is simulated by the first digital filter. The frequency band and volume of the third signal can be adjusted via the equalizer in a state in which the response characteristic of the sound transmission path from the sound wave detection sensor to the interference sound wave detection sensor is reflected in the third signal. The target signal can be selected from the third signal via the equalizer under the assumption that it is generated at the position of the interference sound wave detection sensor. The sound field space control system arbitrarily and freely adjusts the frequency characteristic of the sound at the position of the interfering acoustic wave detection sensor to the desired frequency characteristic by converting the third signal into a target signal having the desired frequency characteristic by an equalizer. since it is possible, the sound propagating on the position of the interference wave detection sensor can be surely changed to the sound having frequency characteristics desired, it is possible to make the sound of preference at the position of the interference wave detection sensor.

  In the sound field space control system in which the target signal generation device is formed of a delay correction device and an equalizer, the time delay until the first sound wave propagates from the synthesized sound wave detection sensor to the interference sound wave detection sensor is corrected by the delay correction device. The frequency band and volume of the third signal can be adjusted via the equalizer in a state where the time delay between the synthetic sound wave detection sensor and the interference sound wave detection sensor is corrected. The target signal can be selected from the third signal via the equalizer, assuming that the signal is generated at the position. The sound field space control system arbitrarily and freely adjusts the frequency characteristic of the sound at the position of the interfering acoustic wave detection sensor to the desired frequency characteristic by converting the third signal into a target signal having the desired frequency characteristic by an equalizer. since it is possible, the sound propagating on the position of the interference wave detection sensor can be surely changed to the sound having frequency characteristics desired, it is possible to make the sound of preference at the position of the interference wave detection sensor.

  A sound field space control system including a reverb in which a target signal generating device adjusts a reverberation characteristic of a third signal. The reverberation converts the third signal into a target signal to which a desired reverberation characteristic is added. The reverberation characteristics at the position of the sensor can be arbitrarily and freely adjusted to the desired reverberation characteristics, so that the sound propagated to the position of the interference sound wave detection sensor can be reliably changed to a sound having the desired reverberation, and interference sound wave detection Sounds with the desired reverberation can be created at the sensor location. In this sound field space control system, it is possible to individually listen to the sound of reverberation characteristics desired by the audience, to the audience located in the vicinity of the interference sound wave detection sensor.

  The sound field space control system in which the interference signal generation device is formed of an adaptive digital filter and an adaptive control calculation unit is used to update the adaptive digital filter by using the error signal, and the adaptive digital filter updates the interference signal. Is generated, and the frequency band arbitrarily selected using the second sound wave generated from the sound wave generator is amplified, attenuated, and silenced while following the change of the sound wave in the sound field space and the change of the target signal. Thus, the sound propagated to the position of the interference sound wave detection sensor can be reliably changed to a sound having a desired frequency characteristic. This sound field space control system can adjust the reverberation characteristics by using the second sound wave generated from the sound wave generator while following the change of the sound wave in the sound field space and the change of the target signal. The sound propagated to the sensor position can be reliably changed to a sound having a desired reverberation.

  In the sound field space control system in which the interference signal generation device includes the second digital filter, the time series transfer characteristic from the second sound wave generation device to the interference sound wave detection sensor is simulated by the second digital filter. The adaptive digital filter can be updated using the error signal while considering the response characteristics of the sound transmission path from the sound wave generator to the interference sound wave detection sensor, and the sound propagated to the position of the interference sound wave detection sensor can be The sound can be reliably changed to have a characteristic. This sound field space control system can adjust the reverberation characteristics by using the second sound wave generated from the sound wave generator, and ensures that the sound propagated to the position of the interference sound wave detection sensor is a sound having the desired reverberation. Can be changed.

  Since the sound field space control system having a sampling frequency in the range of 3 kHz to 40 kHz samples at the frequency within a unit time, the frequency band selected using the second sound wave generated from the second sound wave generator is selected. Amplification, attenuation, and mute can be performed, and the sound propagated to the position of the interference sound wave detection sensor can be reliably changed to a sound having a desired frequency characteristic. This sound field space control system can adjust the reverberation characteristics by using the second sound wave generated from the sound wave generator, and ensures that the sound propagated to the position of the interference sound wave detection sensor is a sound having the desired reverberation. Can be changed.

  In the sound field space control system in which the number of interference sound wave detection sensors is the same as the number of sound wave generation devices or more than the number of sound wave generation devices, the number of interference sound wave detection sensors is arranged, and interference spreads in the control target space of the sound field. By causing the interference sound wave detection sensors to detect sound waves, the second signal output from the interference sound wave detection sensor can be approximated to the target signal as much as possible, and the sound propagated to the position of the interference sound wave detection sensor can be obtained at a desired frequency. The sound can be reliably changed to have a characteristic. This sound field space control system can adjust the reverberation characteristics by using the second sound wave generated from the sound wave generator, and ensures that the sound propagated to the position of the interference sound wave detection sensor is a sound having the desired reverberation. Can be changed.

  The sound field space control system in which the synthetic sound wave detection sensor is disposed in the vicinity of the sound source, and the sound wave generator and the interference sound wave detection sensor are disposed in the vicinity of the audience who listens to the interference sound wave has a frequency arbitrarily selected at the audience position. The band can be amplified, attenuated, and silenced, and the sound propagated to the audience position can be changed to a sound having a frequency characteristic desired by the audience. The sound field space control system can adjust the reverberation characteristics by using the second sound wave generated from the sound wave generator, and can ensure that the sound propagated to the position of the audience has the reverberation desired by the audience. Can be changed.

  The details of the sound field space control system according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a sound field space control system 10A shown as an example, and FIG. 2 is a conceptual diagram showing an example of a sound field space 12 using the system 10A. FIG. 3 is a diagram illustrating response characteristics, and FIG. 4 is a diagram illustrating time-series transfer characteristics between the microphones 13, 14, 15 and speakers 16, 17.

  In FIG. 2, the vertical direction is indicated by an arrow X, the front-rear direction is indicated by an arrow Y, and the horizontal direction is indicated by an arrow Z. A sound field space 12 shown in FIG. 2 indicates an internal space of a concert hall, a multipurpose hall, a live house, an opera house, a lecture room, or a listening room. In FIG. 4, the time series transfer characteristics from the adjustment speakers 16 and 17 (sound wave generator) to the reference microphone 13 (synthetic sound wave detection sensor) are (Hr), and the error microphones 14 and 15 (interference) are transmitted from the adjustment speakers 16 and 17. The time-series transfer characteristics from the reference microphone 13 to the error microphones 14 and 15 are represented by (C ′). In FIG. 2, only one audience 20 is illustrated, but there are actually a large number of audiences, and microphones 14 and 15 and speakers 16 and 17 are arranged in the vicinity of the audience.

  This sound field space control system 10 </ b> A controls sound generated from the sound source 11 and propagating through the sound field space 12 using first and second two-system (two-channel) control units. However, the number of control units is not particularly limited, and the number of units may be one system, four systems, eight systems, sixteen systems, or the like. The sampling frequency in the system 10A is in the range of 3 kHz to 40 kHz, preferably in the range of 10 kHz to 40 kHz, and more preferably in the range of 20 kHz to 40 kHz.

  The sound source 11 can exemplify music performed by an orchestra, a song (music) sung by a singer, a speaker's voice (voice), and a music broadcast output from a speaker. Note that the sound generated from the sound source 11 includes not only music and voice but also any other sound such as a cry, a natural environment sound, and a sound effect. The sound source 11 exists inside the sound field space 12. Note that the sound field space 12 is not limited to the interior space of a concert hall, multipurpose hall, live house, opera house, lecture room, listening room, but a space in a vehicle such as a car, an airplane, or a train, a building, or a general house. The system 10A can be used for any other sound field space in a building such as an outdoor hall, a gymnasium, an indoor sports field, a dome stadium, an outdoor stadium, a dome soccer field, and an outdoor soccer field.

  The first control unit includes a reference microphone 13 (synthetic sound wave detection sensor), first and second error microphones 14 and 15 (first and second interference sound wave detection sensors), and a first adjustment speaker 16. (First sound wave generator) and the first controller 18. The reference microphone 13, the error microphones 14 and 15, and the adjustment speaker 16 are connected to the controller 18 via an interface.

  The second control unit includes a reference microphone 13 (synthetic sound wave detection sensor), first and second error microphones 14 and 15 (second interference sound wave detection sensor), and a second adjustment speaker 17 (second sound source). And a second controller 19. The reference microphone 13, the error microphones 14 and 15, and the adjustment speaker 17 are connected to the controller 19 via an interface. The first and second control units share one reference microphone 13 and share the first and second error microphones 14 and 15.

  When the control unit has four systems, the first to fourth error microphones, adjustment speakers, and controllers are required. When the control unit has eight systems, the first to eighth error microphones and adjustment speakers. Need a controller. As long as the number of control units is not limited, it is possible to install control units up to the n-th system. In this case, the first to nth error microphones, the first to nth adjustment speakers, and the first to nth controllers are required. The number of error microphones is the same as that of the adjustment speakers, but the number of error microphones may be larger than that of the adjustment speakers.

  The reference microphone 13 is arranged in the vicinity of the sound source 11 in the sound field space 12. Here, the vicinity of the sound source 11 refers to a position separated from the sound source 11 by about 1 to 100 cm in the sound propagation direction. The reference microphone 13 is preferably disposed in the vicinity of the sound source 11, but may be disposed between the sound source 11 and the adjustment speakers 16 and 17 and at a position separated from the sound source 11 by a predetermined dimension. However, it is not always necessary to be arranged near the sound source 11. The reference microphone 13 is connected to an amplifier (not shown) that amplifies the sound wave detected by the reference microphone 13. An A / D converter (not shown) is connected between the controllers 18 and 19 and the amplifier.

  The reference microphone 13 detects a synthesized sound wave of analog music (first sound wave) generated from the sound source 11 and an analog second sound wave described later generated from the adjustment speakers 16 and 17, and uses the detected synthesized sound wave as an amplifier. Output. However, when the system 10A is activated, the reference microphone 13 detects only music. The synthesized sound wave is amplified by an amplifier and then converted into a digital first input signal (first signal) by an A / D converter. The first input signal is output from the A / D converter to the controllers 18 and 19.

  The first and second adjustment speakers 16 and 17 are disposed in the vicinity of the audience 20 in the sound field space 12. Here, the vicinity of the audience 20 means a position separated from the audience 20's ear by about 3 to 100 cm. The adjustment speakers 16 and 17 are preferably arranged in the vicinity of the audience 20, but may be arranged at a position separated by a predetermined dimension from the sound source 11 with the reference microphone 13 in between. There is no need to be located nearby. The adjustment speakers 16 and 17 generate a second sound wave that interferes with music in the sound field space 12. An amplifier (not shown) that amplifies the second sound wave is connected to the adjustment speakers 16 and 17. A D / A converter (not shown) is connected between the controllers 18 and 19 and the amplifier.

  The first and second error microphones 14 and 15 are arranged in the vicinity of the audience 20 in the sound field space 12 with the adjustment speakers 16 and 17 interposed therebetween. Here, the vicinity of the audience 20 means a position separated from the ear of the audience 20 by about 1 to 100 cm. The error microphones 14 and 15 are preferably disposed in the vicinity of the audience 20, but may be disposed at a predetermined distance from the reference microphone 13 with the adjustment speakers 16 and 17 interposed therebetween. It need not be located in the vicinity of the audience 20. The error microphones 14 and 15 are connected to an amplifier (not shown) that amplifies the detected sound wave. An A / D converter (not shown) is connected between the controller and the amplifier.

  The error microphones 14 and 15 detect the interference sound wave (error sound wave) generated by the interference between the music (first sound wave) and the second sound wave, and output the detected interference sound wave to the amplifier. However, when the system 10A is activated, the error microphones 14 and 15 detect only music. The interference sound wave is amplified by an amplifier and then converted to a digital second input signal (second signal) by an A / D converter. The second input signal is output from the A / D converter to the controllers 18 and 19.

The first and second controllers 18, 19 include pseudo feedback signal generation filters 21, 22, third signal output devices 23, 24, 25, 26, interference signal generation devices 27, 28, target signal generation devices 29, 30, Error signal output devices 31, 32, 33, and 34 are provided. Although not shown in the figure, the controllers 18 and 19 are central units that cause the filters 21 and 22 and their devices 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, and 34 to execute various means. The computer includes a processing unit and a large-capacity storage unit (memory) that stores various pieces of data. A central processing unit of the controllers 18 and 19 has a DSP (Digital
A signal processor (CPU) is used, but a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) can also be used. When the control unit is installed up to the n-th system, the first to n-th pseudo feedback signal generation filters, the first to n-th third signal output devices, the first to n-th interference signal generation devices, the first to n-th interference signal generation devices, The nth target signal generation device and the first to nth error signal output devices are required. However, the target signal generation device is not necessarily required up to the n-th, and one controller can share it.

  The controller 19 generates a predetermined interference signal through the filters 21 and 22 and their devices 23,24,25,26,27,28,29,30,31,32,33,34, adjusting speaker A second sound wave is generated in the sound field space 12 through 16 and 17, and a predetermined frequency band of the music is amplified, attenuated, and extinguished by utilizing the interference between the music and the second sound wave. Moreover, the reverberation time of music is extended by utilizing the interference between music and the second sound wave. Although not shown in the figure, input devices such as a keyboard and a mouse and output devices such as a display and a printer are connected to the controllers 18 and 19 via an interface.

  The internal address file of the storage unit stores the filters 21 and 22 and their devices 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, and 34 via the central processing unit. An application for executing each means is stored. Based on the control by the operating system stored in the storage unit, the central processing unit of the controllers 18 and 19 activates the application from the storage unit, and according to the activated application, the filters 21 and 22 and their devices 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, and 34 are caused to execute the following means. The central processing unit causes the interference signal generation devices 27 and 28 to generate digital interference signals (interference signal generation means), and causes the pseudo feedback signal generation filters 21 and 22 to generate digital pseudo feedback signals (pseudo feedback signal generation means). ).

  The central processing units of the controllers 18 and 19 cause the interference signals to be output from the interference signal generators 27 and 28 to the adjustment speakers 16 and 17 (interference signal output means), and the pseudo feedback signal from the pseudo feedback signal generation filters 21 and 22. The third signal output devices 23, 24, 25, and 26 are made to output (pseudo feedback signal output means).

  The interference signal is a signal that becomes a second sound wave having a phase and a sound pressure for amplifying a specific frequency band among music generated from the sound source 11 and propagated through the sound field space 12, or a specific sound among the music. It is a signal that becomes a second sound wave having a phase and sound pressure that attenuates the frequency band, or a signal that becomes a second sound wave having a sound pressure opposite to that of a specific frequency band to be silenced in music. The pseudo feedback signal is a signal that can be estimated (identified) as the second sound wave that reaches the reference microphone 13 from the adjustment speakers 16 and 17.

  The central processing unit of the controllers 18 and 19 causes the third signal output devices 23, 24, 25, and 26 to generate a third input signal (third signal) by removing the pseudo feedback signal from the first input signal (third signal). Generating means) and outputting the third input signal from the third signal output devices 23, 24, 25, 26 to the interference signal generating devices 27, 28 and the target signal generating devices 29, 30 (third signal output means). The central processing unit causes the target signal generating devices 29 and 30 to generate a target signal having a desired frequency characteristic after interference with the second sound wave from the third input signal (target signal generating means), and generate the target signal as a target signal. The error signals are output from the devices 29 and 30 to the error signal output devices 31, 32, 33 and 34 (target signal output means). The central processing unit causes the error signal output devices 31, 32, 33, and 34 to generate an error signal by removing the target signal from the second input signal (error signal generating means), and the error signal is output to the error signal output devices 31, 32. , 33 and 34 are output to the interference signal generators 27 and 28 (error signal output means).

  They pseudo feedback signal generating filter 21 and 22, as shown in FIG. 4, to simulate the time series transfer characteristics from adjusting the speaker 16, 17 to Reference lance microphone 13 (Hr). The filters 21 and 22 reflect the time-series transfer characteristics (Hr) (impulse response) in the sound transmission path from the adjustment speakers 16 and 17 to the reference microphone 13 estimated in advance in the third signal output devices 23 and 24. , 25, 26 perform feedforward control on the third signal output devices 23, 24, 25, 26 so that the pseudo feedback signal can be subtracted from the first input signal. As shown in FIG. 3, the time series transfer characteristic 60 is a response characteristic at the sound receiving point 63 when the sound wave 62 (pulse) generated from the sound source 61 propagates through the transmission path 63 and reaches the sound receiving point 64. is there. That is, the time-series transfer characteristic (Hr) is determined by the second sound wave at the position of the microphone 13 when the second sound wave generated from the adjustment speakers 16 and 17 propagates through the sound field space 12 and reaches the reference microphone 13. The response characteristics are shown.

  The interference signal generation devices 27 and 28 update the first to second digital filters 35 and 36 (second digital filter), the adaptive digital filters 37 and 38, and the first to first digital filters 37 and 38 that update the adaptive digital filters 37 and 38. 2 adaptive control arithmetic units 39 and 40 (Filtered-XLMS algorithm). These digital filters 35 and 36 simulate time series transfer characteristics (C) from the adjustment speakers 16 and 17 to the error microphones 14 and 15 as shown in FIG. The digital filters 35 and 36 reflect the time-series transfer characteristics (C) (impulse response) in the sound transmission path from the adjustment speakers 16 and 17 to the error microphones 14 and 15 estimated in advance, in an adaptive control calculation unit 39. , 40 can update the adaptive digital filters 21, 22 with respect to the adaptive control arithmetic units 39, 40. The time-series transfer characteristic (C) indicates that the second sound wave generated from the adjustment speakers 16 and 17 propagates through the sound field space 12 and reaches the error microphones 14 and 15 at the positions of the error microphones 14 and 15. The response characteristics of two sound waves are shown.

  The adaptive control arithmetic units 39 and 40 update the adaptive digital filters 37 and 38 based on the adaptive control algorithm. The adaptive digital filters 37 and 38 generate an interference signal that amplifies a specific frequency band in the first sound wave propagating through the sound field space 12 while responding to a change in the acoustic environment of the sound field space 12. Among the sound waves, an interference signal for attenuating a specific frequency band is generated, and an interference signal having a sound pressure opposite to that of the specific frequency band to be silenced is generated.

  The target signal generating devices 29 and 30 are formed of digital filters 41 and 42 (first digital filter) and equalizers 43 and 44 (frequency characteristic adjusting device). As shown in FIG. 4, the digital filters 41 and 42 simulate time series transfer characteristics (C ′) from the reference microphone 13 to the error microphones 16 and 17. The digital filters 41 and 42 perform feed-forward control on the equalizers 43 and 44 based on the time-series transfer characteristics (C ′) in the sound transmission path from the reference microphone 13 to the error microphones 16 and 17 estimated in advance. The time series transfer characteristic (C ′) is a response characteristic of the first sound wave at the position of the error microphones 16 and 17 when the first sound wave propagating through the sound field space 12 reaches the error microphones 16 and 17 from the reference microphone 13. Is shown.

  The equalizers 43 and 44 convert the third input signal into a target signal having a desired frequency characteristic by adjusting the volume of the frequency band while selecting an arbitrary frequency band from the third input signal. Output a signal. As the equalizers 43 and 44, a 1 octave audio graphic equalizer, a 1/3 octave audio graphic equalizer, or the like can be used.

  The control procedure in the system 10A of FIG. 1 will be described as an example where music is played in the concert hall (sound field space 12). When music is played, the music (first sound wave) propagates to the internal space (sound field space 12) of the concert hall. When the system 10A is activated, the controllers 18 and 19 perform the filters 21 and 22 and their devices 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 in accordance with the applications stored in the storage unit. , 34 execute various means. The music reaches the reference microphone 13 and then reaches the error microphones 14 and 15 while propagating three-dimensionally in the vertical and horizontal directions and in the front-rear direction in the interior space of the concert hall as indicated by an arrow f1 in FIG. As advance preparations for executing various means in the system 10A, before playing music, the equalizers 43 and 44 are adjusted to select a frequency band, and the volume of the frequency band is set. Alternatively, during performance of music, the equalizers 43 and 44 are adjusted to select a frequency band, and the volume of the frequency band is set.

  In the frequency band in which the volume of the equalizers 43 and 44 is set to (+), the target signal for amplifying the frequency band is an interference signal from the target signal generation devices 29 and 30 via the error signal output devices 31, 32, 33 and 34. The data is output to the generation devices 27 and 28. As a result, the adjustment speakers 16 and 17 output the second sound wave so as to increase the sound of the selected frequency band among the music sounds at the positions of the error microphones 14 and 15. In the frequency band in which the volume of the equalizers 43 and 44 is set to (−), a target signal that attenuates the frequency band is an interference signal from the target signal generation devices 29 and 30 via the error signal output devices 31, 32, 33, and 34. The data is output to the generation devices 27 and 28. As a result, the adjustment speakers 16 and 17 output the second sound wave so as to weaken the sound in the selected frequency band among the music sounds at the positions of the error microphones 14 and 15. When the volume of the equalizers 43 and 44 is set to (−) maximum, the target signal for muting the selected frequency band interferes with the target signal generators 29 and 30 via the error signal output devices 31, 32, 33, and 34. It is output to the signal generators 27 and 28. As a result, the adjustment speakers 16 and 17 output the second sound wave so as to mute the sound of the selected frequency band among the music sounds at the positions of the error microphones 14 and 15.

  At the time of activation of the system 10A, the second sound wave is not generated from the adjusting speakers 16 and 17, music (first sound wave) is detected by the reference microphone 13, and further propagates through the internal space of the concert hall as it is. The error microphones 14 and 15 are reached, and music is detected by the error microphones 14 and 15. The reference microphone 13 that has detected the music outputs the music to the amplifier. The amplifier amplifies the music and then outputs the music to the A / D converter. The A / D converter converts the music into a digital first input signal, and then outputs the first input signal to the third signal output devices 23, 24, 25, and 26. The error microphones 14 and 15 that have detected the music output the music to the amplifier. The amplifier amplifies the music and then outputs the music to the A / D converter. The A / D converter converts the music into a digital second input signal, and then outputs the second input signal to the error signal output devices 31, 32, 33, and 34.

  Since no pseudo feedback signal is generated in the pseudo feedback signal generation filters 21 and 22 when the system 10A is activated, the output signal of the pseudo feedback signal output from the pseudo feedback signal generation filters 21 and 22 is (0). When the system 10A is activated, the third signal output devices 23, 24, 25, and 26 subtract the pseudo feedback signal (0) from the first input signal to obtain a third input signal (a signal having the same value as the first input signal). ) (Third signal generation means), and outputs the third input signal to the interference signal generation devices 27 and 28 and the target signal generation devices 29 and 30 (third signal output means).

  The digital filters 41 and 42 (first digital filters) forming the target signal generation devices 29 and 30 have time series transfer characteristics (C ′) in the sound transmission path from the reference microphone 13 to the error microphones 14 and 15 estimated in advance. A convolution operation is performed on the third input signal, and a time delay until the music propagates from the reference microphone 13 to the error microphones 14 and 15 is corrected, and the response characteristics of the music are made to match those of the music at the positions of the error microphones 14 and 15. . The digital filters 41 and 42 output the third input signal to the equalizers 43 and 44 in a state where the time-series transfer characteristic (C ′) is reflected in the third input signal.

  The equalizers 43 and 44 convert the third input signal into a target signal having a preset frequency characteristic (target signal generating means), and output the target signal to the error signal output devices 31, 32, 33, and 34 ( Target signal output means). In the equalizers 43 and 44, the volume of the frequency band to be amplified is set to (+), the volume of the frequency band to be attenuated is set to (−), and the volume of the frequency band to be muted is set to (−) maximum. Error signal output device at the time of startup of the system 10A 31, 32, 33, 34, from the second input signal representative of the first sound wave by subtracting the target signal calculating an error signal (error signal generating means), the error signal To the interference signal generators 27 and 28 (error signal output means).

  Specifically, it is as follows. For the frequency band that remains without being amplified, attenuated, or muted, the volume of the equalizers 43 and 44 is set to ± (0). As a result, a signal having the same homologous amplitude as the second input signal is output to the error signal output devices 31, 32, 33, and 34, and the error signal becomes (0). In the frequency band to be amplified, the volumes of the equalizers 43 and 44 are set to (+). As a result, a signal having substantially the same phase as the second input signal and a large amplitude is output to the error signal output devices 31, 32, 33, and 34, and an error signal having a phase substantially opposite to the phase of the second input signal is output as the error signal. Output from the output devices 31, 32, 33, 34 to the interference signal generators 27, 28. Conversely, in the frequency band to be attenuated, the volume levels of the equalizers 43 and 44 are set to (−). As a result, a small signal amplitude at the second input signal and substantially the same phase is outputted to the error signal output device 31, 32, 33 and 34, the error signal as a phase substantially the same phase of the second input signal by the error signal output The signals are output from the devices 31, 32, 33, 34 to the interference signal generating devices 27, 28. Further, in the frequency band to be silenced, the volume of the equalizers 43 and 44 is set to (−) maximum. As a result, the signal (0) is output to the error signal output devices 31, 32, 33, and 34, and the error signal having the same homologous amplitude as the second input signal is output from the error signal output devices 31, 32, 33, and 34 as an interference signal. The data is output to the generation devices 27 and 28.

  At the time of activation of the system 10A, the value of the error signal, which is the difference between the target signal in the frequency band to be amplified and the second input signal, becomes maximum, and the difference between the target signal in the frequency band to be attenuated or silenced and the second input signal The value of the error signal is the maximum. The digital filters 35 and 36 (second digital filter) forming the interference signal generation devices 27 and 28 have a third time series transfer characteristic (C) from the adjustment speakers 16 and 17 to the error microphones 14 and 15 estimated in advance. A convolution operation is performed on the input signal, and the result is output to adaptive control operation sections 39 and 40.

  The adaptive control arithmetic units 39 and 40 update the adaptive digital filters 37 and 38 using the error signal while considering the time series transfer characteristic (C). Specifically, the adaptive control arithmetic units 39 and 40 generate a Δ adaptive digital filter (ΔADF), which is an update amount of the adaptive digital filter, at a predetermined time interval in accordance with the sampling frequency (3 kHz to 40 kHz), and the Δ adaptive digital filter Is added to the current adaptive digital filter (ADF) to update the adaptive digital filters 37 and 38 from the present to the future.

  The interference signal generators 27 and 28 convolve the adaptive digital filters 37 and 38 with the third input signals output from the third signal output devices 31, 32, 33, and 34 to increase or decrease the second input signal. An interference signal is generated in accordance with the sampling frequency (interference signal generation means). The interference signal generation devices 27 and 28 output the generated interference signals to the pseudo feedback signal generation filters 21 and 22 and the D / A converter (interference signal output means). The D / A converter converts the digital interference signal into an analog second sound wave, and outputs the second sound wave to the amplifier. The amplifier amplifies the second sound wave and outputs the amplified second sound wave to the adjustment speakers 16 and 17.

  The adjusting speakers 16 and 17 generate the second sound wave in the interior space of the concert hall. As indicated by an arrow f2 in FIG. 2, the second sound wave propagates three-dimensionally from the speakers 16 and 17 through the interior space of the concert hall in the vertical and horizontal directions and in the front-rear direction, and reaches the reference microphone 13 as well as the error microphone 14. , 15. The second sound wave travels toward the error microphones 14 and 15 while interfering with the music (first sound wave), and completely interferes with the frequency band to be amplified in the music at the position of the error microphones 14 and 15, and the sound in that frequency band. Make it stronger. Further, it completely interferes with the frequency band of the music to be attenuated at the position of the error microphones 14 and 15, and weakens the sound in that frequency band. Furthermore, it completely interferes with the frequency band to be silenced in the music at the position of the error microphones 14 and 15, and cancels the sound in that frequency band.

  When the system 10A is continuously operated, the error signal gradually decreases, and finally the error signal level becomes (0) and the error disappears. The disappearance of the error represents the coincidence between the second signal, which is the signal of the error microphones 14 and 15, and the target signal having the desired frequency characteristic, and represents the state in which the signals of the error microphones 14 and 15 coincide with the desired frequency characteristic. .

  During the operation of the system 10 </ b> A, the second sound wave directed to the reference microphone 13 is synthesized with music, and the synthesized sound wave is detected by the reference microphone 13. Further, the second sound wave directed toward the error microphones 14 and 15 interferes with music at the positions of the microphones 14 and 15, and those interference sound waves are detected by the error microphones 14 and 15. The synthesized sound wave is amplified by an amplifier, converted to a digital first input signal by an A / D converter, and output to the third signal output devices 31, 32, 33, and 34.

  The pseudo feedback signal generation filters 21 and 22 perform a convolution operation on the time series transfer characteristic (Hr) in the sound transmission path from the adjustment speakers 16 and 17 to the reference microphone 13 estimated in advance to generate an interference feedback signal. (Pseudo feedback signal generating means). The pseudo feedback signal generation filters 21 and 22 output the generated pseudo feedback signals to the third signal output devices 23, 24, 25, and 26 (pseudo feedback signal output means). The third signal output devices 23, 24, 25, and 26 generate a third input signal by subtracting a pseudo feedback signal that can be estimated as the second sound wave from the synthesized signal (third signal generation means), and the third input. The signal is output to the interference signal generators 27 and 28 and the target signal generators 29 and 30 (third signal output means). In the target signal generating devices 29 and 30, a target signal is generated by the digital filters 41 and 42 and the equalizers 43 and 44 (target signal generating means). The target signal is output from the target signal generating devices 29, 30 to the error signal output devices 31, 32, 33, 34 (target signal output means).

  The error microphones 14 and 15 that have detected the interfering sound wave during operation of the system 10A output the interfering sound wave to the amplifier. The amplifier amplifies the interference sound wave, and then outputs the interference sound wave to the A / D converter. The A / D converter converts the interfering sound wave into the second input signal, and then outputs the second input signal to the error signal output devices 31, 32, 33, and 34. The error signal output devices 31, 32, 33, and 34 generate an error signal by subtracting the target signal from the second input signal representing the interfering sound wave (error signal generating means), and the error signal is converted into the interference signal generating device 27, 28 (error signal output means). At this time, the level of the error signal, which is the difference between the target signal and the second input signal, is smaller than when the system 10A is activated.

  In the interference signal generation devices 27 and 28, the adaptive control calculation units 39 and 40 update the adaptive digital filters 37 and 38 according to the sampling frequency using the error signal while taking the time series transfer characteristic (C) into consideration. The interference signal generation devices 27 and 28 convolve the adaptive digital filters 37 and 38 with the third input signals output from the third signal output devices 31, 32, 33 and 34 to generate interference signals (interference signal generation). means). The interference signal generation devices 27 and 28 output the generated interference signals to the pseudo feedback signal generation filters 21 and 22 and the D / A converter (interference signal output means). The D / A converter converts the digital interference signal into an analog second sound wave, and outputs the second sound wave to the amplifier. The amplifier amplifies the second sound wave and outputs the amplified second sound wave to the adjustment speakers 16 and 17.

  The adjusting speakers 16 and 17 generate the second sound wave in the interior space of the concert hall. The second sound wave travels toward the error microphones 14 and 15 while interfering with the music (first sound wave), and interferes with the frequency band of the music to be amplified at the position of the error microphones 14 and 15, thereby strongly strengthening the sound in that frequency band. To do. In addition, it interferes with the frequency band of the music to be attenuated at the position of the error microphones 14 and 15, and weakens the sound in that frequency band. Further, at the position of the error microphones 14 and 15, it interferes with the frequency band to be silenced in the music and cancels the sound in that frequency band.

  When the frequency band to be amplified is changed and the volume of the frequency band is set to (+) while the system 10A is in operation, the target signal generators 29 and 30 receive new target signals corresponding to the changed frequency band and volume. The target signal is generated and output from the target signal generation devices 29 and 30 to the error signal output devices 31, 32, 33, and 34, and the sound of the changed frequency band becomes strong. When the frequency band to be attenuated is changed and the volume of the frequency band is set to (−) while the system 10A is in operation, the target signal generators 29 and 30 receive new target signals corresponding to the changed frequency band and volume. The target signal is generated and output from the target signal generation devices 29 and 30 to the error signal output devices 31, 32, 33 and 34, and the sound of the changed frequency band becomes weak. When the frequency band to be silenced is changed while the system 10A is in operation, and the volume of the frequency band is set to (−) maximum, the target signal generators 29 and 30 will generate new target signals corresponding to the changed frequency band and volume. The target signal is output from the target signal generation devices 29 and 30 to the error signal output devices 31, 32, 33, and 34, and the sound of the changed frequency band is silenced.

  This system 10A can freely change the frequency band and its volume to be amplified, attenuated and silenced by adjusting the frequency band and volume via the equalizers 43 and 44 during its operation. The frequency band to be amplified, attenuated, and muffled during operation of the system 10A and the volume thereof can be freely selected according to changes in the sound environment, preferences, and the like. Even if the frequency band or volume is changed during operation, the system 10A quickly generates an interference signal corresponding to the changed frequency, and the second sound wave corresponding to the interference signal is generated by the adjustment speaker 16, 17, the desired frequency band can be immediately amplified, attenuated, and silenced.

  FIG. 5 is a diagram showing an example of sound amplification and attenuation effects (experimental results) by this system 10A. In FIG. 5, the frequency characteristic of the sound field space 12 when the system 10A is OFF is indicated by a dotted line L1, the frequency characteristic of the sound field space 12 when the system 10A is ON is indicated by a solid line L2, and the frequency characteristic of the target signal is indicated by a one-dot chain line L3. It shows with. In FIG. 5, the vertical axis represents the sound pressure level, and the horizontal axis represents the frequency. In the system 10A, the frequency characteristics shown in FIG. 5 can be monitored in time series via a display, and the monitored frequency characteristics can be output via a printer. Further, the monitored frequency characteristics can be stored in the storage unit in time series.

  After the system 10A is activated, the equalizer 43 is configured so that the frequency band of 100 (Hz) to 300 (Hz) is attenuated and the frequency band of 600 (Hz) to 900 (Hz) is amplified while playing music. , 44 to adjust the frequency band and volume. As a result, as shown in FIG. 5, the frequency band of 100 (Hz) to 300 (Hz) is immediately attenuated, and approximately approximates the frequency characteristic of the target signal, and the frequency band of 600 (Hz) to 900 (Hz). Amplified immediately and approximated the frequency characteristics of the target signal.

  Sound field space control system 10A includes a target signal generating device 29, 30 is converted into a target signal having a frequency characteristic desired to third input signals, the error signal output device 31, 32, 33, 34 from the second input signal An error signal obtained by subtracting the target signal is output, and the third input signal received by the interference signal generation devices 27 and 28 from the third signal output devices 23, 24, 25 and 26 and the error signal output devices 31 and 32. , 33, and 34, the error signal received from the error microphones 14 and 15 is output using the error signals received from the error microphones 14 and 15, so that the second input signals output from the error microphones 14 and 15 can be approximated to the target signal. The music at the positions of the microphones 14 and 15 can be arbitrarily and freely adjusted to music having a desired frequency characteristic. The system 10A can arbitrarily and freely select a frequency band to be strengthened, a frequency band to be weakened, and a frequency band to be erased from music propagating in the sound field space 12, and amplify, attenuate, and mute only the selected frequency band. By doing so, music at the positions of the error microphones 14 and 15 can be changed to music having a desired frequency characteristic, and favorite music can be created at the positions of the error microphones 14 and 15. This system 10 </ b> A allows the audience 20 located in the vicinity of the error microphones 14 and 15 to individually listen to music having a frequency characteristic desired by the audience 20.

  The sound field space control system 10A arranges a plurality of adjustment speakers 16, 17 and propagates the second sound wave uniformly from the speakers 16, 17 to the three-dimensional space to be controlled in the sound field. The second sound wave can be reliably interfered with the music spreading in the space, and the music at the positions of the error microphones 14 and 15 can be reliably changed to music having a desired frequency characteristic. In this system 10A, a plurality of error microphones 14 and 15 are arranged, and by causing the error microphones 14 and 15 to detect interfering sound waves that spread in the three-dimensional space to be controlled in the sound field, the error microphones 14 and 15 output them. The second input signal can be approximated to the target signal as much as possible, and the music at the positions of the error microphones 14 and 15 can be reliably changed to music having a desired frequency characteristic.

  The sound field space control system 10A generates a third input signal by removing the pseudo feedback signal that the third signal output devices 23, 24, 25, and 26 can estimate as the second input signal from the first input signal, Since the input signal is output to the interference signal generation devices 27 and 28 and the target signal generation devices 29 and 30, the reference microphone is added to the third input signal output to the interference signal generation devices 27 and 28 and the target signal generation devices 29 and 30. The pseudo feedback signal that estimates the second sound wave reaching 13 is not included, and howling in the reference microphone 13 can be prevented.

  When the combined signal including the interference signal is output to the interference signal generation devices 27 and 28 as it is, an interference signal including a sound wave that amplifies, attenuates, and silences the interference signal is generated. In this system 10A, the combined signal is generated. Since the third input signal excluding the pseudo feedback signal is output to the interference signal generation devices 27 and 28, it is possible to prevent the interference signal from including sound waves that amplify, attenuate, and mute the interference signal. Further, when an interference signal is included in the signals output to the target signal generation devices 29 and 30, a combined signal of the first input signal and the interference signal is output to the target signal generation devices 29 and 30, and is amplified, attenuated, and silenced. In this system 10A, the third input signal obtained by removing the pseudo feedback signal from the synthesized signal is output to the target signal generating devices 29 and 30, so that the target signal generating device is selected. In 29 and 30, the frequency band to be amplified, attenuated, and silenced can be surely selected.

  In the sound field space control system 10A, the time series transfer characteristics (C ′) from the reference microphone 13 to the error microphones 14 and 15 are simulated by the digital filters 41 and 42, and therefore the sound filter from the reference microphone 13 to the error microphones 14 and 15 is simulated. The frequency band and volume of the third input signal can be adjusted via the equalizers 43 and 44 in a state where the response characteristic of the sound transmission path is reflected in the third input signal, and the third input signal becomes the error microphone 14, The target signal can be selected from the third input signal via the equalizers 43 and 44 under the assumption that the signal is generated at the position 15.

  In the sound field space control system 10A, the digital filters 35 and 36 simulate the time series transfer characteristics (C) until the second sound wave propagates from the adjustment speakers 16 and 17 to the error microphones 14 and 15, so that adaptive control is performed. The arithmetic units 39 and 40 can update the adaptive digital filters 37 and 38 using the error signal while taking into account the response characteristics of the sound transmission path from the adjustment speakers 16 and 17 to the error microphones 14 and 15. The frequency band selected at the position of the error microphones 14 and 15 can be reliably amplified, attenuated, and silenced while following changes in the acoustic environment and the target signal in the space 12. Since the sampling frequency of the system 10A is in the range of 3 kHz to 40 kHz, the system 10A can approach the interfering sound wave of the band where the second sound wave is desired to be amplified and the interfering sound wave of the band where it is desired to be attenuated as much as possible, and the second sound wave is silenced. It can be as close as possible to the sound with the opposite phase and sound pressure in the desired band.

  FIG. 6 is a configuration diagram of a sound field space control system 10B shown as another example. The system 10B shown in FIG. 6 differs from that shown in FIG. 1 in that the target signal generators 29 and 30 include reverbs 45 and 46 in addition to the digital filters 41 and 42 (first digital filter) and the equalizers 43 and 44. located point, because other configurations are identical to those of the system 10A of FIG. 1, by the same reference numerals and the system 10A of FIG. 1, description of the other configurations in the system 10B will be omitted. In this system 10B, target signal generating devices 29 and 30 are formed of digital filters 41 and 42, equalizers 43 and 44, and reverbs 45 and 46, respectively. The reverbs 45 and 46 adjust the reverberation characteristics of the target signal. In this system 10B, the central processing units of the controllers 18 and 19 cause the reverb 45 and 46 to execute reverberation characteristic setting means for setting a predetermined reverberation characteristic to the target signal. The sampling frequency in this system 10B is in the range of 3 kHz to 40 kHz, similar to that in FIG.

  The interference signal in the system 10B is a signal that becomes a second sound wave having a phase and a sound pressure for amplifying a specific frequency band among music generated from the sound source 11 and propagating through the sound field space 12, or A signal that becomes a second sound wave having a phase and a sound pressure that attenuates a specific frequency band in music, or a signal that becomes a second sound wave having a phase opposite to the specific frequency band to be silenced in music, Furthermore, it is a signal that becomes a second sound wave that extends from the reverberation time of music that is generated from the sound source 11 and propagates through the sound field space 12.

  The control procedure in the system 10B of FIG. 6 will be described as follows by taking as an example the case where music is played in the concert hall (sound field space 12) as in the system 10A with the aid of FIG. In this system 10B, before playing music, the equalizers 43 and 44 are adjusted to select a frequency band, the volume of the frequency band is set, and the reverb 45 and 46 are adjusted to set the reverberation characteristics. Alternatively, during performance of music, the equalizers 43 and 44 are adjusted to select a frequency band, the volume of the frequency band is set, and the reverb 45 and 46 is adjusted to set the reverberation characteristics.

  When the reverberations 45 and 46 are set to arbitrary reverberation characteristics, a target signal having the reverberation characteristics is transmitted from the target signal generation apparatuses 29 and 30 to the interference signal generation apparatus 27 via the error signal output apparatuses 31, 32, 33, and 34. , 28. As a result, the adjustment speakers 15 and 16 output the second sound wave so that the reverberation characteristics of the music at the positions of the error microphones 14 and 15 have a desired reverberation characteristic.

  When music is played, the music (first sound wave) propagates to the interior space of the concert hall. The music detected by the reference microphone 13 at the time of activation of the system 10B is amplified by an amplifier, then converted to a digital first input signal by an A / D converter, and the third signal output device 23, 24, 25, and 26. The third signal output devices 23, 24, 25, and 26 subtract the pseudo feedback signal (0) from the first input signal to generate a third input signal (third signal generating means), and the third input signal It outputs to the interference signal generators 27 and 28 and the target signal generators 29 and 30 (third signal output means). The music detected by the error microphones 14 and 15 at the time of activation of the system 10B is amplified by an amplifier, converted to a digital second input signal by an A / D converter, and an error signal output device 31 as a second input signal. , 32, 33, 34.

  The digital filters 41 and 42 convolutionally calculate the time-series transfer characteristic (C ′) in the sound transmission path from the reference microphone 13 to the error microphones 14 and 15 estimated in advance to the third input signal, and the reference microphone 13 to the error microphone 14. , 15 while correcting the time delay until the music propagates, the response characteristics of the music are made to match those of the music at the positions of the error microphones 14, 15. The digital filters 41 and 42 output the third input signal to the equalizers 43 and 44 in a state where the time-series transfer characteristic (C ′) is reflected in the third input signal.

  Equalizer 43 converts the target signal having a predetermined frequency characteristic of the third input signal (target signal generating means), and outputs the target signal reverb 45 and 46. The reverbs 45 and 46 set a reverberation characteristic set in advance as a target signal (reverberation characteristic setting means), and output the target signal to the error signal output devices 31, 32, 33, and 34 (target signal output means). Error signal output device at the time of startup of the system 10A 31, 32, 33, 34, from the second input signal representative of the first sound wave by subtracting the target signal calculating an error signal (error signal generating means), the error signal To the interference signal generators 27 and 28 (error signal output means).

  The digital filters 35 and 36 convolutionally calculate the time-series transfer characteristics (C) from the adjustment speakers 16 and 17 to the error microphones 14 and 15 estimated in advance to the third input signal, and the result is the adaptive control calculation unit 39, Output to 40. The adaptive control arithmetic units 39 and 40 update the adaptive digital filters 37 and 38 using the error signal while considering the time series transfer characteristic (C). The update of the adaptive digital filters 37 and 38 in the adaptive control arithmetic units 39 and 40 is the same as that in the system 10A of FIG.

  The interference signal generators 27 and 28 convolve the adaptive digital filters 37 and 38 with the third input signals output from the third signal output devices 31, 32, 33, and 34 to increase or decrease the second input signal. An interference signal is generated in accordance with the sampling frequency (interference signal generation means). The interference signal generation devices 27 and 28 output the generated interference signals to the pseudo feedback signal generation filters 21 and 22 and the D / A converter (interference signal output means). The interference signal is converted into an analog second sound wave by the D / A converter, then amplified by the amplifier, and output to the adjustment speakers 16 and 17 as the second sound wave.

  The adjusting speakers 16 and 17 generate the second sound wave in the interior space of the concert hall. The second sound wave interferes with the frequency band of the music to be amplified at the position of the error microphones 14 and 15, and strengthens the sound in that frequency band. In addition, it interferes with the frequency band of the music to be attenuated at the position of the error microphones 14 and 15, and weakens the sound in that frequency band. Further, at the position of the error microphones 14 and 15, it interferes with the frequency band to be silenced in the music and cancels the sound in that frequency band. The second sound wave becomes a sound wave that extends the reverberation time of the music at the position of the error microphones 14 and 15, and extends the reverberation time of the sound.

  During operation of the system 10B, a synthesized sound wave of music and the second sound wave is detected by the reference microphone 13, and an interference sound wave of the music and the second sound wave is detected by the error microphones 14 and 15. The synthesized sound wave is amplified by an amplifier, converted to a digital first input signal by an A / D converter, and output to a third signal output device. As in the system 10A of FIG. 1, the pseudo feedback signal generation filters 21 and 22 convolve the time series transfer characteristic (Hr) with the interference signal to generate a pseudo feedback signal (pseudo feedback signal generation means). The pseudo feedback signal is output to the third signal output devices 23, 24, 25, and 26 (pseudo feedback signal output means). The third signal output devices 23, 24, 25, and 26 generate a third input signal by subtracting the pseudo feedback signal from the combined signal (third signal generation means), and use the third input signal as the interference signal generation device 27. , 28 and the target signal generators 29, 30 (third signal output means). In the target signal generating devices 29 and 30, a target signal is generated by the digital filters 41 and 42, the equalizers 43 and 44, and the reverbs 45 and 46 (target signal generating means). The target signal is output from the target signal generating devices 29, 30 to the error signal output devices 31, 32, 33, 34 (target signal output means).

  The interference sound wave is amplified by an amplifier, converted to a digital second input signal by an A / D converter, and output to an error signal output device. The error signal output devices 31, 32, 33, 34 subtract the target signal from the second input signal to generate an error signal (error signal generating means), and output the error signal to the interference signal generating devices 27, 28. (Error signal output means). At this time, the level of the error signal, which is the difference between the target signal and the second input signal, is smaller than when the system 10B is activated.

  In the interference signal generation devices 27 and 28, the adaptive control calculation units 39 and 40 update the adaptive digital filters 37 and 38 according to the sampling frequency using the error signal while taking the time series transfer characteristic (C) into consideration. The interference signal generation devices 27 and 28 convolve the adaptive digital filters 37 and 38 with the third input signals output from the third signal output devices 23, 24, 25, and 26 to generate interference signals (interference signal generation). means). The interference signal generation devices 27 and 28 output the generated interference signals to the pseudo feedback signal generation filters 21 and 22 and the D / A converter (interference signal output means). The interference signal is converted into an analog second sound wave by the D / A converter, then amplified by the amplifier, and output to the adjustment speakers 16 and 17 as the second sound wave.

  The adjusting speakers 16 and 17 generate the second sound wave in the interior space of the concert hall. The second sound wave interferes with a selected frequency band of music at the position of the error microphones 14 and 15, and amplifies, attenuates, or disappears the frequency band. The second sound wave extends the reverberation time of the music so that the music has the desired reverberation characteristics at the positions of the error microphones 14 and 15.

  When the reverberation time is changed via the reverb 45 and 46 during the operation of the system 10B, and the reverberation time is set, the target signal generators 29 and 30 generate new target signals to which the changed reverberation characteristics are added, The target signal is output from the target signal generation devices 29, 30 to the error signal output devices 31, 32, 33, 34. As a result, the reverberation time of the music is changed.

  During operation of the system 10B, the frequency band and volume can be freely changed by adjusting the frequency band and volume via the equalizers 43 and 44, and the reverb 45 and 46 can be freely changed. The reverberation time of the sound can be freely changed via Even if the frequency band, volume, and reverberation characteristics are changed during operation, the system 10B quickly generates an interference signal corresponding to the changed frequency, and the second sound wave corresponding to the interference signal is used for adjustment. Since the signals are output from the speakers 16 and 17, a desired frequency band can be immediately amplified, attenuated, and silenced, and music can have desired reverberation characteristics.

  This sound field space control sound system 10B has the following effects in addition to the effects of the system 10A of FIG. The system 10B arbitrarily and freely adjusts the reverberation characteristic at the position of the error microphones 14 and 15 to the desired reverberation characteristic by converting the third input signal to the target signal of the desired reverberation characteristic by the reverb 45 and 46. Therefore, the music propagated to the position of the error microphones 14 and 15 can be surely changed to music having a desired reverberation, and music having a desired reverberation can be made at the positions of the error microphones 14 and 15. . This system 10B allows the audience 20 located in the vicinity of the error microphones 14 and 15 to individually hear music having reverberation characteristics desired by the audience 20.

  FIG. 7 is a block diagram of a sound field space control system 10C shown as another example, and FIG. 8 shows time-series transfer characteristics and time delays between microphones 13, 14, 15 and speakers 16, 17 in this system 10C. FIG. The system 10C shown in FIG. 7 is different from that shown in FIG. 6 in that delay correction devices 47 and 48 are used instead of the digital filters 41 and 42, and other configurations are different from those of the system 10B shown in FIG. Since they are the same, the same reference numerals as those of the systems 10A and 10B in FIGS. 1 and 6 are attached, and the description of other configurations in the system 10C is omitted. In this system 10C, target signal generation devices 29 and 30 are formed of delay correction devices 47 and 48, equalizers 43 and 44, and reverbs 45 and 46, respectively. The delay correction devices 47 and 48 correct the time delay S until the music (first sound wave) propagates from the reference microphone 13 to the error microphones 14 and 15. Note that the sampling frequency in the system 10C is in the range of 3 kHz to 40 kHz, similar to that in FIGS. 1 and 6.

  The control procedure in the system 10C of FIG. 7 will be described as an example in the case where music is played in the concert hall (sound field space 12) as in the systems 10A and 10B with the aid of FIG. is there. Before the music is played, the equalizers 43 and 44 are adjusted to select a frequency band, the volume of the frequency band is set, and the reverb 45 and 46 are adjusted to set the reverberation characteristics. Alternatively, during performance of music, the equalizers 43 and 44 are adjusted to select a frequency band, the volume of the frequency band is set, and the reverb 45 and 46 is adjusted to set the reverberation characteristics.

  When music is played, the music (first sound wave) propagates to the internal space (sound field space 12) of the concert hall. The music detected by the reference microphone 13 at the time of activation of the system 10C is amplified by an amplifier, then converted to a digital first input signal by an A / D converter, and a third signal output device 23, 24, 25, and 26. The third signal output devices 23, 24, 25, and 26 subtract the pseudo feedback signal (0) from the first input signal to generate a third input signal (third signal generating means), and the third input signal It outputs to the interference signal generators 27 and 28 and the target signal generators 29 and 30 (third signal output means). The music detected by the error microphones 14 and 15 when the system 10C is activated is amplified by an amplifier, converted to a digital second input signal by an A / D converter, and an error signal output device 31 as a second input signal. , 32, 33, 34.

  The delay correction devices 47 and 48 forming the target signal generation devices 29 and 30 correct the time delay S of the music from the reference microphone 13 to the error microphones 14 and 15, so that the time delay S becomes the third input signal. In the reflected state, the third input signal is output to the equalizers 43 and 44. The equalizers 43 and 44 convert the third input signal into a target signal having a preset frequency characteristic (target signal generating means), and output the target signal to the reverbs 45 and 46. The reverbs 45 and 46 set a reverberation characteristic set in advance as a target signal (reverberation characteristic setting means), and output the target signal to the error signal output devices 31, 32, 33, and 34 (target signal output means). Error signal output device at the time of startup of the system 10C 31, 32, 33, 34, from the second input signal representative of the first sound wave by subtracting the target signal calculating an error signal (error signal generating means), the error signal To the interference signal generators 27 and 28 (error signal output means).

  The digital filters 35 and 36 convolutionally calculate the time-series transfer characteristics (C) from the adjustment speakers 16 and 17 to the error microphones 14 and 15 estimated in advance to the third input signal, and the result is the adaptive control calculation unit 39, Output to 40. The adaptive control arithmetic units 39 and 40 update the adaptive digital filters 37 and 38 using the error signal while considering the time series transfer characteristic (C). The update of the adaptive digital filters 37 and 38 in the adaptive control arithmetic units 39 and 40 is the same as that in the system 10A of FIG.

  The interference signal generators 27 and 28 convolve the adaptive digital filters 37 and 38 with the third input signals output from the third signal output devices 23, 24, 25, and 26 to increase or decrease the second input signal. An interference signal is generated in accordance with the sampling frequency (interference signal generation means). The interference signal generation devices 27 and 28 output the generated interference signals to the pseudo feedback signal generation filters 21 and 22 and the D / A converter (interference signal output means). The interference signal is converted into an analog second sound wave by the D / A converter, then amplified by the amplifier, and output to the adjustment speakers 16 and 17 as the second sound wave.

  The adjusting speakers 16 and 17 generate the second sound wave in the interior space of the concert hall. The second sound wave interferes with the frequency band of the music to be amplified at the position of the error microphones 14 and 15, and strengthens the sound in that frequency band. In addition, it interferes with the frequency band of the music to be attenuated at the position of the error microphones 14 and 15, and weakens the sound in that frequency band. Further, at the position of the error microphones 14 and 15, it interferes with the frequency band to be silenced in the music and cancels the sound in that frequency band. The second sound wave becomes a sound wave that extends the reverberation time of the music at the position of the error microphones 14 and 15, and extends the reverberation time of the sound.

  During operation of the system 10 </ b> C, a synthesized sound wave of music and the second sound wave is detected by the reference microphone 13, and an interference sound wave of the music and the second sound wave is detected by the error microphones 14 and 15. The synthesized sound wave is amplified by an amplifier, converted to a digital first input signal by an A / D converter, and output to the third signal output devices 23, 24, 25, and 26. As in the system 10A of FIG. 1, the pseudo feedback signal generation filters 21 and 22 convolve the time series transfer characteristic (Hr) with the interference signal to generate a pseudo feedback signal (pseudo feedback signal generation means). The pseudo feedback signal is output to the third signal output devices 23, 24, 25, and 26 (pseudo feedback signal output means). The third signal output devices 23, 24, 25, and 26 generate a third input signal by subtracting the pseudo feedback signal from the combined signal (third signal generation means), and use the third input signal as the interference signal generation device 27. , 28 and the target signal generators 29, 30 (third signal output means). In the target signal generating devices 29 and 30, a target signal is generated by the delay correcting devices 47 and 48, the equalizers 43 and 44, and the reverbs 45 and 46 (target signal generating means). The target signal is output from the target signal generating devices 29, 30 to the error signal output devices 31, 32, 33, 34 (target signal output means).

  The interference sound wave is amplified by an amplifier, converted to a digital second input signal by an A / D converter, and output to error signal output devices 31, 32, 33, and 34. The error signal output devices 31, 32, 33, and 34 generate an error signal by subtracting the target signal from the second input signal (error signal generation means), and output the error signal to the interference signal generation devices 29 and 30. (Error signal output means). At this time, the level of the error signal, which is the difference between the target signal and the second input signal, is smaller than when the system 10C is activated.

  In the interference signal generation devices 29 and 30, the adaptive control calculation units 39 and 40 update the adaptive digital filters 37 and 38 according to the sampling frequency using the error signal while taking the time series transfer characteristic (C) into consideration. The interference signal generation devices 29 and 30 perform convolution operations of the adaptive digital filters 37 and 38 on the third input signals output from the third signal output devices 23, 24, 25, and 26 to generate interference signals (interference signal generation). means). The interference signal generation devices 29 and 30 output the generated interference signals to the pseudo feedback signal generation filters 21 and 22 and the D / A converter (interference signal output means). The interference signal is converted into an analog second sound wave by the D / A converter, then amplified by the amplifier, and output to the adjustment speakers 16 and 17 as the second sound wave.

  The adjusting speakers 16 and 17 generate the second sound wave in the interior space of the concert hall. The second sound wave interferes with a selected frequency band of music at the position of the error microphones 14 and 15, and amplifies, attenuates, or disappears the frequency band. The second sound wave extends the reverberation time of the music so that the music has the desired reverberation characteristics at the positions of the error microphones 14 and 15. During operation of the system 10C, by adjusting the frequency band and volume via the equalizers 43 and 44, the frequency band and the volume to be amplified, attenuated, and silenced can be freely changed. The reverberation time of music can be changed freely.

  The effect of the sound field space control system 10C is different from that of the system 10B of FIG. 6 because the digital filters 41 and 42 are replaced by the delay correction devices 47 and 48, as follows. In this system 10C, since the time delay S until the music (first sound wave) propagates from the reference microphone 13 to the error microphones 14 and 15 is corrected by the delay correction devices 47 and 48, the reference microphone 13 and the error microphones 14, 15, the frequency band and volume of the third input signal can be adjusted via the equalizers 43 and 44 in a state where the time delay S between the third input signal and the reference microphone 15 is corrected. It is possible to select the target signal from the third input signal via the equalizers 43 and 44 under the assumption that the signal is generated in the above. The system 10C has the same effects as the system 10B of FIG. 6 in addition to the effects described above. However, the effects of the system 10B of FIG. 6 are used, and description of other effects of the system 10C is omitted.

The block diagram of the sound field space control system shown as an example. The conceptual diagram which shows an example of the sound field space using a system. The figure explaining a response characteristic. The figure showing the time-sequential transfer characteristic between a microphone and a speaker. The figure which shows an example of the amplification and attenuation effect (experiment result) of the sound by a system. The block diagram of the sound field space control system shown as another example. The block diagram of the sound field space control system shown as another example. The figure showing the time-sequential transfer characteristic and time delay between a microphone and a speaker.

Explanation of symbols

10A Sound field space control system 10B Sound field space control system 10C Sound field space control system 11 Sound source 12 Sound field space 13 Reference microphone (synthetic sound wave detection sensor)
14 First error microphone (interference sound wave detection sensor)
15 Second error microphone (interference sound wave detection sensor)
16 First speaker for adjustment (sound wave generator)
17 Second speaker for adjustment (sound wave generator)
Reference Signs List 18 first controller 19 second controller 21 pseudo feedback signal generation filter 22 pseudo feedback signal generation filter 23 third signal output device 24 third signal output device 25 third signal output device 26 third signal output device 27 interference signal generation Device 28 Interference signal generator 29 Target signal generator 30 Target signal generator 31 Error signal output device 32 Error signal output device 33 Error signal output device 34 Error signal output device 35 Digital filter (second digital filter)
36 Digital filter (second digital filter)
37 Adaptive Digital Filter 38 Adaptive Digital Filter 39 Adaptive Control Operation Unit 40 Adaptive Control Operation Unit 41 Digital Filter (First Digital Filter)
42 Digital filter (first digital filter)
43 Equalizer 44 Equalizer 45 Reverb 46 Reverb 47 Delay Correction Device 48 Delay Correction Device

Claims (10)

First to first sound waves are generated in the sound field space that are arranged at a predetermined distance from the sound source that generates the first sound wave in the sound field space and interfere with the first sound wave that propagates from the sound source in the sound field space. An nth sound wave generator;
A synthetic sound wave detection sensor that is disposed between the sound source and the sound wave generator, detects a synthetic sound wave of the first sound wave and the second sound wave, and outputs the detected synthetic sound wave as a first signal;
The first to nth sound wave generators are disposed with a predetermined distance from the synthetic sound wave detection sensor, and the interference sound wave generated by the interference between the first sound wave and the second sound wave is detected and detected. First to nth interference sound wave detection sensors that output the interference sound wave as a second signal;
First to nth pseudo feedback signals that have a corresponding relationship with the first to nth sound wave generators and generate pseudo feedback signals that estimate the second sound waves that reach the synthetic sound wave detection sensor from the sound wave generators. Generation filter,
The first to n-th pseudo feedback signal generation filters have a corresponding relationship, receive a first signal from the synthetic sound wave detection sensor, receive a pseudo feedback signal from the pseudo feedback signal generation filter, and First to nth third signal output devices for outputting a third signal obtained by removing the pseudo feedback signal from the signal;
A target signal that receives the third signal from the first to nth third signal output devices, adjusts the frequency characteristic of the third signal, and converts the third signal into a target signal having a desired frequency characteristic. A generating device;
The first to nth interference sound wave detection sensors have a corresponding relationship, receive a second signal from the interference sound wave detection sensors, receive a target signal from the target signal generation device, and receive the second signal from the second signal. First to nth error signal output devices for outputting an error signal excluding a target signal;
Corresponding to the first to nth sound wave generators, the third signals received from the first to nth third signal output devices and received from the first to nth error signal output devices The first to nth interference signal generation devices that generate an interference signal that becomes the second sound wave using an error signal and output the generated interference signal to the first to nth sound wave generation devices. Sound field space control system.   The target signal generation device amplifies a first digital filter that simulates a time-series transfer characteristic from the synthetic sound wave detection sensor to the interference sound wave detection sensor, and a volume of an arbitrarily selected frequency band of the third signal. The sound field space control system according to claim 1, wherein the sound field space control system is formed of an equalizer for attenuating.   The target signal generation device is arbitrarily selected from a delay correction device that corrects a time delay until the first sound wave propagates from the synthetic sound wave detection sensor to the interference sound wave detection sensor, and the third signal. The sound field space control system according to claim 1, wherein the sound field space control system is formed of an equalizer that amplifies or attenuates the volume of a frequency band.   The sound field space control system according to claim 2 or 3, wherein the target signal generation device includes a reverb that adjusts a reverberation characteristic of the third signal.   The interference signal generation device is formed of an adaptive digital filter for generating the interference signal and an adaptive control arithmetic unit that updates the adaptive digital filter using an error signal received from the error signal output device. The sound field space control system according to any one of claims 1 to 4.   The interference signal generation device includes a second digital filter that simulates a time series transfer characteristic from the sound wave generation device to the interference sound wave detection sensor, and the adaptive control arithmetic unit simulates a time series that the second digital filter simulates. The sound field space control system according to claim 5, wherein the adaptive digital filter is updated using a transfer characteristic and an error signal received from the error signal output device.   The sound field space control system according to any one of claims 1 to 6, wherein a sampling frequency in the sound field space control system is in a range of 3 kHz to 40 kHz.   The interference wave number of the detecting sensor, the sound field space control system according to claim 1 or any one of claims 7 larger than the number of same number as or the sound-wave generator of the wave generator.   9. The synthetic sound wave detection sensor is disposed in the vicinity of the sound source, and the sound wave generator and the interference sound wave detection sensor are disposed in the vicinity of an audience who listens to the interference sound wave. The sound field space control system described in 1.   10. The sound field space is an internal space of a concert hall, a multipurpose hall, a live house, an opera house, a lecture room, or a listening room, and the first sound wave is music or sound. The sound field space control system according to any one of the above.

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