JP5671894B2 - Acoustic adjustment support method, acoustic adjustment support device, and program - Google Patents

Description

  The present invention relates to a technique for supporting adjustment of sound radiated from a speaker installed in an acoustic space such as a concert hall.

  In theaters, movie theaters, concert halls, etc., it is common practice to squeeze speech, musical accompaniment, singing voices, musical instrument performances, etc. with a loudspeaker and radiate it toward the audience. In such a case, if the sound radiated from the speaker contains a lot of frequency components corresponding to the resonance frequency of the acoustic space, a resonance phenomenon may occur, and it may be difficult to listen to speech or musical sound. Therefore, in general, various filters such as a notch filter are provided in front of the speaker installed in the acoustic space, and a specific frequency component that causes a resonance phenomenon is electrically removed by filtering from an audio signal applied to the speaker. Has been done. In addition, depending on the characteristics of the reflected sound that is reflected on each surface (such as a wall or ceiling) that partitions the acoustic space and arrives at the spectator seat, there may be a problem that the sound in the low frequency range increases or decreases. For this reason, the intensity of the frequency component that causes problems such as increase or decrease in low-frequency sound is adjusted in advance by the filter processing.

  In order to properly realize the above various filter processes, it is necessary to appropriately adjust the setting, for example, by setting an appropriate filter coefficient for a filter arranged in front of the speaker. For example, in an aspect in which removal of a specific frequency component is realized by a notch filter, filter coefficients calculated in the following manner are set. That is, the center frequency indicating the position of the dip is determined according to the specific frequency, the Q level indicating the attenuation level and the steepness of the attenuation is determined according to the intensity of the specific frequency component, etc. The filter coefficient is calculated using the attenuation level and the Q value as parameters for defining the filter processing. Hereinafter, adjusting the frequency response in the acoustic space of the sound radiated from the speaker by appropriately adjusting the setting of the filter provided in the front stage of the speaker is referred to as “acoustic adjustment”.

  Such acoustic adjustment is generally performed by an acoustic engineer who is a professional engineer when installing the speaker in an acoustic space. Conventionally, acoustic adjustment has often been performed on a trial and error basis based on the skill and experience of an acoustic engineer, relying on the audibility of sound emitted from a speaker. However, in such an aspect, there is a problem that the adjustment result greatly depends on the skill, sensitivity, physical condition, etc. of the acoustic engineer. Therefore, various techniques that enable objective and quantitative acoustic adjustment have been proposed, and examples thereof include those disclosed in Patent Documents 1 to 6. In the technologies disclosed in these Patent Documents 1 to 6, acoustic adjustment is realized in the following manner. First, a predetermined input signal (for example, an impulse signal) is given to a speaker installed in the acoustic space to emit sound, and the sound is collected by a microphone installed in the acoustic space. A frequency response (amplitude characteristic or phase characteristic) obtained by performing FFT on the output signal of the microphone and a frequency response (hereinafter referred to as a target characteristic) for a sound to be heard by the audience as a sound corresponding to the input signal. The difference is obtained, and the acoustic adjustment is performed so that the difference between the two is eliminated.

Patent 3901648 Patent 3920233 JP 2008-252932 A Patent 2530474 Patent 2530475 Japanese Patent No. 2571091

The differences obtained by the techniques disclosed in Patent Documents 1 to 6 reflect the effects caused by the spatial characteristics of the entire acoustic space, such as the size and shape of the acoustic space, and the sound absorption characteristics of the sound reflecting surface of the acoustic space. Effects due to spatial influence components and local characteristics near the speaker installation location (for example, if it is installed near the wall, the shape of the wall near the installation location, surface material, finish, etc.) The reflected position-influence component is included. Since the spatial influence component and the position influence component are originally separate and independent, when performing acoustic adjustment, it is necessary to grasp both separately and adjust each component separately as an acoustic adjustment method. desirable. This is because, for example, if the sound adjustment for the speaker installed at a certain position in the acoustic space can be performed independently for each of the spatial influence component and the position influence component, for example, only the situation around the installation position of the speaker is changed. This is because it is sufficient to readjust only the position-influence component. Similarly, if the situation in the vicinity of the speaker installation position does not change greatly and only the spatial characteristics of the acoustic space have changed, only the spatial influence component needs to be readjusted. As an example of the case where the characteristics in the vicinity of the speaker installation position do not change greatly and only the spatial characteristics of the acoustic space change, an example is a stage in an acoustic space such as a multipurpose hall having a movable stage reflector. Perform the sound adjustment with a part of the reflector (front reflector etc.) installed, and use the same acoustic equipment, remove the stage reflector and change the curtain equipment without changing the speaker installation position. When there is a performance that performs acoustic adjustment again in the installed state (specifically, a performance with the subject of orchestra performance and explanation of music, etc. and a performance mainly of speech using sound equipment with ordinary curtain equipment) Etc.). As described above, as an acoustic adjustment method, it is desirable to grasp each of the spatial influence component and the position influence component separately and adjust each of the components separately, but these are disclosed in Patent Documents 1 to 6. In the technology that has been adopted, the spatial influence component and the position influence component are regarded as one, and it is not possible to obtain both separately and independently.
The present invention has been made in view of the above-described problems, and provides a technique that enables the spatial influence component and the position influence component to be grasped separately and independently in acoustic adjustment and to adjust each quantitatively. Objective.

  In order to solve the above-described problems, the present invention adjusts the setting of a filter disposed in front of a speaker installed at a predetermined position in the acoustic space, and the sound radiated from the speaker is adjusted in the acoustic space. An acoustic adjustment support method for adjusting the frequency response of the speaker, wherein the speaker is held in the acoustic space away from the sound reflection surface of the acoustic space, and the speaker is arranged by a microphone disposed in the far area of the service area. The frequency response including the influence of the reflecting surface of the speaker is measured, and the difference between the measured frequency response and the target characteristic which is the frequency response of the speaker not including the influence of the reflecting surface is given to the speaker. A space in which the difference in the frequency band where the correlation between the input signal and the output signal of the microphone is high reflects the influence caused by the spatial characteristics of the entire acoustic space. A spatial influence component specifying step for specifying as a sound component, and an influence of a reflecting surface in the vicinity of the installation position of the speaker by a microphone placed at a predetermined position in the service area and located far away or nearby in the service area. The frequency response is measured, and the difference in the frequency band in which the correlation between the input signal applied to the speaker and the output signal of the microphone is high among the difference between the frequency response and the target characteristic, A position influence component specifying step for specifying as a position influence component reflecting an influence caused by a general situation, and a filter setting for adjusting the setting of the filter so that at least one of the spatial influence component and the position influence component is eliminated An acoustic adjustment support method comprising an adjustment step.

  In order to solve the above-described problem, the present invention adjusts the setting of a filter arranged in front of a speaker installed at a predetermined position in the acoustic space so that the sound radiated from the speaker is in the acoustic space. An acoustic adjustment support device for assisting in adjusting a frequency response in the apparatus, wherein an input signal is given to the speaker held away from the sound reflection surface of the acoustic space, and is arranged far away in the service area The frequency response including the influence of the reflection surface for the speaker is calculated from the output signal of the microphone, and the difference between the frequency response and the target characteristic which is the frequency response of the speaker not including the influence of the reflection surface is calculated. In the frequency band in which the correlation between the input signal given to the speaker and the output signal of the microphone is high in the difference between the calculation process and the difference A spatial influence component identification support means for executing processing for assisting a user to specify a minute as a spatial influence component reflecting an influence caused by a spatial characteristic of the entire acoustic space, and the predetermined position The frequency response including the influence of the reflection surface in the vicinity of the installation position is calculated for the speaker from the output signal of the microphone arranged far away or in the vicinity of the service area. The difference between the response and the target characteristic is calculated, and the difference in the frequency band in which the correlation between the input signal applied to the speaker and the output signal of the microphone is high among the differences is determined locally in the vicinity of the speaker installation position. For executing processing that supports the user's identification as a position-influencing component that reflects the influence caused by various situations There is provided an acoustic adjustment support device comprising: an acoustic component specifying unit; and a filter setting adjustment unit that adjusts the setting of the filter so that at least one of the spatial influence component and the position influence component is eliminated. To do. As another aspect of the present invention, a program that causes a computer to function as each of the above means is written and distributed on a computer-readable recording medium such as a CD-ROM (Compact Disk-Read Only Memory), or the Internet. A mode of distribution by downloading via a telecommunication line is also conceivable.

  According to such an acoustic adjustment support method and an acoustic adjustment support apparatus, it is possible to grasp the spatial influence component and the position influence component separately in the acoustic adjustment and quantitatively adjust each separately.

It is a figure which shows the structural example of the acoustic system 1 containing the acoustic adjustment assistance apparatus 80 of one Embodiment of this invention. It is a figure for demonstrating the installation position of the speakers 70-1 and 70-2 in the acoustic space 2. FIG. 3 is a block diagram illustrating a configuration example of the acoustic adjustment support device 80. FIG. 4 is a flowchart showing a procedure of an acoustic adjustment support method using the acoustic system 1. It is a figure for demonstrating the arrangement position of the adjustment object speaker and the microphone 90 in target characteristic acquisition step SA110 of the acoustic adjustment method. It is a figure for demonstrating how to determine the arrangement space | interval of the speaker for adjustment and microphone 90 in the target characteristic acquisition step SA110. It is a figure for demonstrating the arrangement position of the speaker for adjustment and the microphone 90 in space influence component specific step SA120 of the acoustic adjustment method. It is a figure for demonstrating the method of contrasting the average of the impulse response obtained in the spatial influence component specific | specification step SA120, and a target characteristic. It is a figure for demonstrating the arrangement position of the speaker for adjustment and the microphone 90 in position influence component specific step SA130 of the acoustic adjustment method. It is a figure for demonstrating the method of contrast of the average of the impulse response obtained in the same position influence component specific | specification step SA130, and a target characteristic. It is a figure for demonstrating the effect of this embodiment. It is a figure for demonstrating other embodiment of this invention. It is a figure for demonstrating other embodiment of this invention. It is a figure for demonstrating other embodiment of this invention. It is a figure for demonstrating other embodiment of this invention. It is a figure for demonstrating other embodiment of this invention. It is a figure for demonstrating other embodiment of this invention. It is a figure for demonstrating other embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
(A: 1st Embodiment)
(A-1: Configuration)
FIG. 1 is a diagram illustrating a configuration example of an acoustic system 1 including an acoustic adjustment support device 80 according to an embodiment of the present invention. This acoustic system 1 is for performing musical sound reproduction in an acoustic space such as a concert hall and acoustic adjustment performed prior to the musical sound reproduction. In the sound source group 10 in FIG. 1, for example, a sound reproduction device such as a CD (Compact Disk) drive, a microphone such as a stage microphone, and an impulse signal (or white noise signal) that is a measurement signal used for sound adjustment are generated. A noise generator (not shown). In addition, although this embodiment demonstrates the case where the acoustic space where the acoustic system 1 is installed is a closed space divided by the top, bottom, front, back, and left and right surfaces of a concert hall or the like, a floor surface such as an outdoor music hall Of course, it is good even if it is a space having only. This is because even the acoustic space having only the floor surface is the sound reflection surface.

  In the acoustic system 1 shown in FIG. 1, each audio signal output from each device belonging to the sound source group 10 is given to the mixer 20, and after mixing by the mixer 20, the acoustic adjustment support device 80, selectors 50-1 and 50-. Is given to 2. If the switch 30 of FIG. 1 is in the ON state, the audio signal output from the mixer 20 is also given to the FIR (Finite Impulse Response) filter 40 via the switch 30. The ON / OFF control of the switch 30 is performed by the acoustic adjustment support device 80. Specifically, under the control of the acoustic adjustment support device 80, the switch 30 is turned on when the musical sound is reproduced using the acoustic system 1, and is turned off during the acoustic adjustment process. It is. Although detailed illustration is omitted in FIG. 1, when the audio signal output from the sound source group 10 is in an analog format, the A / D conversion is performed by the A / D converter and then the mixer 20 is applied. You should give it.

  The FIR filter 40 is, for example, a DSP (Digital Signal Processor), and performs an FIR filter process for adjustment such as removal of a specific frequency component on the audio signal given from the mixer 20 to generate an audio signal to be given to each speaker and output it. To do. Each of the selectors 50-1 and 50-2 is supplied with the audio signal output from the FIR filter 40 and the audio signal output from the mixer 20. Each of these selectors 50-1 and 50-2 outputs either an audio signal output from the FIR filter 40 or an audio signal output from the mixer 20 to the amplifier 60 under the control of the acoustic adjustment support device 80. To do. Specifically, when performing playback control of musical sounds or the like using the acoustic system 1, each of the selectors 50-1 and 50-2 outputs an audio signal provided from the FIR filter 40 to the amplifier 60, and performs acoustic adjustment. In the execution process, the audio signal supplied from the mixer 20 is output to the amplifier 60. The audio signals output from each of the selectors 50-1 and 50-2 are amplified by the amplifier 60 and then D / A converted by a D / A converter (not shown), and then the speakers 70-1 and 70. -2 to be emitted as sound. In the present embodiment, the case where the output system of the acoustic adjustment support device 80 is two systems of the speakers 70-1 and 70-2 will be described.

  Each of the speakers 70-1 and 70-2 in FIG. 1 is a speaker having directivity, and is installed at a predetermined position in the acoustic space. FIG. 2 is a diagram illustrating an example of an installation mode of each of the speakers 70-1 and 70-2 in the acoustic space 2. As shown in FIG. 2, in the acoustic space 2, there are provided a stage 2A where a musical sound is played and a spectator seat group 2B where a spectator is seated. The speakers 70-1 and 70-2 are installed so that the audience seat group 2B is covered by each service area (range in which direct sound from each speaker is provided: not shown in FIG. 2). In the present embodiment, since the purpose is to provide a stereo sound image, the entire audience seat group 2B becomes a service area of each speaker. As shown in FIG. 2, the speakers 70-1 and 70-2 are installed on the left and right sleeves of the stage 2A with their respective directional axes directed toward the center C of the audience seat group 2B. In the sound system 1, the sound reproduction with the sound adjustment completed is realized by appropriately adjusting the filter coefficient applied to the FIR filter 40. 1 is, for example, a personal computer. In addition to ON / OFF control of the switch 30 and switching control of the selectors 50-1 and 50-2, the operation of the mixer 20, the FIR filter 40, and the amplifier 60 is performed. Take control. Specifically, the acoustic adjustment support device 80 adjusts the mixing ratio in the mixer 20 in accordance with an instruction given by the acoustic engineer, calculates the filter coefficient to be given to the FIR filter 40, and sets it. A process of setting a gain in the amplifier 60 is executed.

  In the acoustic system 1 of the present embodiment, a microphone 90 is further connected to the acoustic adjustment support device 80 as shown in FIG. The microphone 90 is used when sound adjustment is performed using the sound adjustment support device 80. More specifically, in the acoustic adjustment in the present embodiment, after the switch 30 is turned OFF and the selectors 50-1 and 50-2 are switched so that the audio signal supplied from the mixer 20 is output to the speaker, An impulse signal is generated in a noise generator included in the sound source group 10, and this impulse signal is given to the speaker 70-1 (or the speaker 70-2) to emit a sound corresponding to the impulse signal. In this way, the sound emitted from the speaker 70-1 (or 70-2) into the acoustic space 2 is collected by the microphone 90. The acoustic adjustment support device 80 uses the frequency response obtained from the output signal of the microphone 90 and the target frequency response (that is, the target amplitude characteristic) for the sound to be heard in the spectator seat group 2B as the sound corresponding to the impulse signal. Alternatively, the filter coefficient is calculated and set in the FIR filter 40 so that the difference is eliminated. Thereby, acoustic adjustment is realized. In the following, the case where the amplitude characteristic is used as the frequency response will be described.

FIG. 3 is a block diagram illustrating a configuration example of the acoustic adjustment support device 80. As shown in FIG. 3, the acoustic adjustment support device 80 includes a control unit 810, an external device interface (hereinafter abbreviated as I / F) group 820, an operation unit 830, a display unit 840, a storage unit 850, and each of these components. A bus 860 that mediates data exchange between them is included. The control unit 810 is, for example, a CPU (Central Processing Unit) and functions as a control center of the acoustic adjustment support device 80. The external device I / F group 820 includes a USB (Universal Serial Bus) interface and a NIC (Network
(Interface Card) is a collection of interface devices for exchanging data with external devices. Each of mixer 20, switch 30, FIR filter 40, amplifier 60, microphone 90, and selectors 50-1 and 50-2 is connected to an appropriate one of a plurality of interface devices included in external device I / F group 820. The The operation unit 830 and the display unit 840 are for providing various user interfaces to a user of the acoustic adjustment support device 80 such as an acoustic engineer. More specifically, the operation unit 830 is a keyboard, for example, and includes a plurality of operators. The operation unit 830 delivers data indicating the contents of operations performed on these operators to the control unit 810. As a result, the operation performed by the user is transmitted to the control unit 810. The display unit 840 is, for example, a liquid crystal display and its drive circuit (both not shown). Various screens that prompt the user to use the acoustic adjustment support device 80 are displayed on the display unit 840 under the control of the control unit 810.

  The storage unit 850 includes a volatile storage unit 852 and a nonvolatile storage unit 854. The volatile storage unit 852 is, for example, a RAM (Random Access Memory), and is used by the control unit 810 as a work area when executing various programs. On the other hand, the nonvolatile storage unit 854 is a hard disk. The nonvolatile storage unit 854 stores in advance an acoustic adjustment support program in addition to a kernel program (not shown) for causing the control unit 810 to implement an OS (Operating System). This sound adjustment support program is a program for causing the control unit 810 to execute processing for supporting the execution of sound adjustment by a sound engineer.

  When the power (not shown) of the acoustic adjustment support device 80 is turned on, the control unit 810 first reads the kernel program from the nonvolatile storage unit 854 to the volatile storage unit 852 and starts executing it. The control unit 810 that implements the OS according to the kernel program executes another program in response to an instruction given via the operation unit 830. For example, when an instruction to execute the acoustic adjustment support program is given via the operation unit 830, the control unit 810 reads the acoustic adjustment support program from the nonvolatile storage unit 854 to the volatile storage unit 852, and executes the execution. Start. The control unit 810 operating according to the acoustic adjustment support program, in response to an instruction given via the operation unit 830, a target characteristic acquisition support process, a spatial influence component identification support process, a position influence component identification support process, and Four processes of the filter coefficient calculation process are executed. Details of these four processes will be clarified in the description of a specific method of acoustic adjustment in the present embodiment in order to avoid duplication, but the outline is as follows.

The target characteristic acquisition support process is a process that supports acquisition of a frequency response (in this embodiment, an amplitude characteristic) representing the target characteristic. The spatial influence component identification support process is a process that assists the acoustic engineer in identifying the spatial influence component. As described above, the spatial influence component means that the sound emitted from the adjustment target speaker (in this embodiment, the speaker 70-1 or the speaker 70-2) to which the impulse signal is given is collected by the microphone 90 in the service area. Of the difference between the frequency response of the audio signal (output signal of the microphone 90) obtained by sound and the target characteristic, this is a difference reflecting the influence caused by the spatial characteristics of the acoustic space 2. The position influence component identification support process is a process that assists the acoustic engineer in identifying the position influence component. As described above, the position influence component is a difference that reflects the influence of the vicinity of the installation position of the speaker to be adjusted among the differences between the frequency response of the output signal of the microphone 90 and the target characteristics. The filter coefficient calculation process is a process for calculating a filter coefficient for individually eliminating the spatial influence component and the position influence component and setting the filter coefficient in the FIR filter 40.
The above is the configuration of the acoustic system 1.

(A-2: Specific execution procedure of acoustic adjustment in this embodiment)
Next, a specific execution procedure of the acoustic adjustment method using the acoustic system 1 will be described.
FIG. 4 is a flowchart showing the procedure of the acoustic adjustment method of the present embodiment. As shown in FIG. 4, the acoustic adjustment method of this embodiment includes four steps: a target characteristic acquisition step SA110, a spatial influence component identification step SA120, a position influence component identification step SA130, and a filter coefficient calculation step SA140. . Of these four steps, the target characteristic acquisition step SA110, the spatial influence component identification step SA120, and the position influence component identification step SA130 are executed for each speaker to be adjusted. Hereinafter, the details of the four steps shown in FIG. 4 will be described by taking the speaker 70-1 as an adjustment target speaker as an example.

The target characteristic acquisition step SA110 is a step of acquiring the target characteristic described above.
In the present embodiment, the original frequency response of the adjustment target speaker (that is, the frequency response inherently possessed by the speaker that does not include the spatial influence component and does not include the position influence component) is set as the target characteristic. This is because it is intended to make it possible to listen to the musical sound or the like in the spectator seat group 2B with the original acoustic characteristics inherent to the speaker to be adjusted. In the target characteristic acquisition step SA110, the acoustic engineer places the adjustment target speaker (that is, the speaker 70-1) and the microphone 90 at a predetermined position in the acoustic space 2, and operates the operation unit 830 to acquire the target characteristic. Input an instruction to execute support processing. The arrangement positions of the adjustment target speaker and the microphone 90 in the target characteristic acquisition step SA110 will be described in detail later.

  The control unit 810 that has received the execution instruction via the operation unit 830 executes target characteristic acquisition support processing. First, the control unit 810 switches the switch 30 to OFF, switches the selectors 50-1 and 50-2 so that the output signal of the mixer 20 is output to the amplifier 60, and then outputs the impulse signal. Operation control of the noise generator of group 10 is performed. Then, the impulse signal is emitted as a sound from the speaker 70-1, and the sound is picked up by the microphone 90 as an impulse response. The control unit 810 receives the output signal of the microphone 90 via the external device I / F group 820, performs FFT on the output signal (impulse response), and converts it into a frequency response. A target characteristic is calculated based on this frequency response.

  The first feature of the acoustic adjustment method of the present embodiment is the arrangement of the adjustment target speaker (speaker 70-1 in this operation example) and the microphone 90 in the acoustic space 2 in the target characteristic acquisition step SA110. FIG. 5 is a diagram illustrating an example of an arrangement mode of the adjustment target speaker and the microphone 90 in the target characteristic acquisition step SA110. More specifically, FIG. 5A is a perspective view of the acoustic space 2 viewed from the left side, and FIG. 5B is a perspective view of the acoustic space 2 viewed from above. As is clear from FIG. 5A and FIG. 5B, in the target characteristic acquisition step SA110, the speaker to be adjusted ignores the reflected sound from the surface in any of the top, bottom, left and right directions of the acoustic space 2. A hollow suspended from the upper surface of the acoustic space 2 away from these surfaces to the extent possible (that is, away from each surface to the extent that the reflected sound from each reflective surface in the acoustic space can be ignored). Held in a state. In the present embodiment, the speaker to be adjusted is held in a hollow state by being suspended from the upper surface of the acoustic space 2, but it is of course possible to hold the speaker in a hollow state by lifting it using a stepladder or the like. . Here, as to how far the speaker to be adjusted is moved from each surface of the acoustic space 2, the reflected sound from each surface is measured, and a distance that makes the reflected sound sufficiently small is determined through appropriate experiments. You can do that. On the other hand, the microphone 90 is arranged at a position separated by a predetermined distance L1 on the same horizontal plane (coaxially) as the adjustment target speaker.

  The predetermined distance L1 is equal to or greater than a distance that allows the adjustment target speaker to be regarded as a point sound source, and the volume of the direct sound radiated from the adjustment target speaker and the reflected sound (indirect sound) from each surface of the acoustic space. It is preferable that the distance is less than a distance (so-called critical distance) at which the sound volume is equal. The reason is as follows. If the distance between the two is too short and the adjustment target speaker cannot be regarded as a point sound source, the adjustment target speaker is composed of a plurality of speaker units (for example, a speaker unit responsible for high-frequency reproduction and a In the case where the speaker unit is in charge of the reproduction of the sound range, etc., the individual acoustic characteristics of each speaker unit appear remarkably, and the acoustic characteristics with the entire adjustment target speaker cannot be obtained. On the other hand, if the distance between the two is too long, the indirect sound becomes dominant and the impulse response inherent in the speaker to be adjusted cannot be obtained. Therefore, it is preferable that the predetermined distance L1 is equal to or longer than a distance at which the adjustment target speaker can be regarded as a point sound source and is less than the critical distance.

  A suitable value of the predetermined distance L1 can be obtained as follows. First, the acoustic engineer sequentially arranges the microphone 90 at a plurality of positions so that the distance from the adjustment target speaker gradually increases, and causes the control unit 810 to acquire the impulse response of the adjustment target speaker at each of these positions. The frequency response of the impulse signal (that is, the input signal given to the speaker 70-1) when these impulse responses are acquired is calculated, and the frequency response of the impulse signal and the frequency response of the impulse response measured at the position are calculated. The control unit 810 calculates a cross-correlation value with The control unit 810 causes the display unit 840 to display the graph of the frequency response of the impulse response acquired at each position and the graph of the cross-correlation value in pairs for each position while matching the frequency axes. The acoustic engineer determines the predetermined distance L <b> 1 with reference to the cross-correlation value graph displayed on the display unit 840. More specifically, the acoustic engineer confirms that the correlation between the frequency response of the impulse signal and the frequency response of the impulse response is maintained at a certain level or more over the entire frequency band (the cross-correlation value is below a predetermined threshold value). On the condition that there is no frequency component), the longest of the plurality of distances corresponding to each position is selected as the predetermined distance L1. That is, the acoustic adjustment support device 80 of the present embodiment positions the graph of the frequency response of the impulse response acquired at each of the plurality of positions and the graph of the cross-correlation value of the frequency response of the impulse response and the frequency response of the impulse signal. Each pair is displayed on the display unit 840 to assist the acoustic engineer in determining the predetermined distance L1. In the present embodiment, the preferred value of the predetermined distance L1 is obtained by measuring the impulse response at a plurality of positions in the service area of the speaker to be adjusted. However, the predetermined value is determined based on the experience of the acoustic engineer. Of course, the distance L1 may be determined.

  For example, FIG. 6 shows a graph coh of cross-correlation values when the distance between the speaker 70-1 and the microphone 90 is 1.5 m, 1.6 m, 1.8 m, 2.0 m, and 2.5 m. And a graph FR of the frequency response obtained from the impulse response. In FIG. 6, the horizontal axis represents frequency (the same applies to FIGS. 8 and 10 to 18), and frequency components whose cross-correlation values are below a predetermined threshold are circled. In the example shown in FIG. 6, if the distance is 1.6 m or less, the correlation between the frequency response of the impulse signal and the frequency response of the impulse response is maintained above a certain level over the entire frequency band. Therefore, in the example shown in FIG. 6, the predetermined distance L1 is determined to be 1.6 m. In the present embodiment, the acoustic adjustment support device 80 executes the process of displaying the frequency response graph FR of the impulse response and the cross-correlation value graph coh on the display unit 840 in pairs for each position of the microphone 90. The acoustic adjustment support device 80 may perform processing such as adding a circle to a frequency component whose cross-correlation value is lower than a predetermined threshold. Further, the criterion of the longest of the distances in which the correlation between the frequency response of the impulse signal (measurement signal) and the frequency response of the impulse response (speaker output signal) is maintained at a certain level or more over the entire frequency band. Accordingly, the sound adjustment support device 80 may be configured to calculate the predetermined distance L1.

  Next, a procedure for acquiring the target characteristic from the frequency response of the impulse response will be described. In the present embodiment, as shown in FIG. 5B, the acoustic engineer arranges the microphone 90 with the predetermined distance L1 in the front direction of the speaker to be adjusted (for example, the directional axis direction), and As shown by a dotted line in FIG. 5B, when the microphone 90 is arranged at a predetermined angle L1 with a predetermined angle (for example, ± 20 ° or ± 40 °) with respect to the front direction. Each of the impulse responses is measured, and the control unit 810 executes processing for calculating a frequency response for each of the impulse responses. The control unit 810 calculates an average of these frequency responses (for example, an addition average for each frequency), and executes a process of writing data representing the average into the nonvolatile storage unit 854 as target characteristic data indicating the target characteristic. That is, in this embodiment, the average of the frequency response of each impulse response obtained by installing the microphone 90 at each of a plurality of positions separated from the adjustment target speaker by a distance L1 in different directions is the target characteristic. . It is not necessarily representative of the frequency response of the sound that the speaker actually radiates in a predetermined angular range to the acoustic space, only by the frequency response in the front direction of the speaker to be adjusted to perform such processing. This is because a comparison with a frequency response in a service area described later cannot be performed appropriately.

Next, the spatial influence component specifying step SA120 will be described.
The spatial influence component identification step SA120 is a step for identifying the spatial influence component. As described above, the spatial influence component is a frequency obtained by performing FFT on an audio signal (impulse response) obtained by picking up sound radiated from an adjustment target speaker given an impulse signal in the service area. Of the difference between the response and the target characteristic, it is a component that reflects the influence caused by the spatial characteristics of the entire acoustic space. In the present embodiment, the spatial influence component is redefined as follows so as to be suitable for objective acoustic identification. That is, in the present embodiment, the average of each frequency response calculated from each impulse response measured by placing the microphone 90 at each of a plurality of distant positions (at least the critical distance or more) within the service area of the speaker to be adjusted. In the frequency response calculated from each impulse response, the frequency response of the impulse response is high in any impulse response, and the correlation between the frequency response of the impulse signal and the frequency response of the impulse signal is high. The difference in the frequency band where the local change mode (how the peaks and valleys appear) is used as the spatial influence component.

  Here, the microphone 90 is arranged far away in the service area of the speaker to be adjusted because the influence of the reflected sound from each surface of the acoustic space is sufficiently reflected and the influence of the direct sound is reduced. This is because the acoustic characteristics of the entire acoustic space are relatively acquired. In addition, the spatial influence component is calculated based on the average of each frequency response obtained by arranging the microphones at a plurality of positions in the service area of the adjustment target speaker in each direction of the acoustic space 2 ( This is to uniformly reflect the influence of the reflected sound from the upper, rear, left and right surfaces. The condition that the correlation between the input signal given to the adjustment target speaker and the output signal of the microphone 90 is a high frequency band is imposed because the consistency between the input signal and the output signal is ensured. The entire acoustic space has the condition that it is a frequency band that has a common local variation in each frequency response. This is because a frequency band that is a unique acoustic feature is extracted and used as a comparison target with target characteristics.

  In the spatial influence component specifying step SA120, the spatial influence component redefined as described above is calculated in the following manner. First, the acoustic engineer places the adjustment target speaker (speaker 70-1) and the microphone 90 at predetermined positions in the acoustic space 2 and operates the operation unit 830, as in the target characteristic acquisition step SA110. The execution instruction of the spatial influence component identification support process is given to the acoustic adjustment support device 80. As in the target characteristic acquisition support process, the control unit 810 switches the selectors 50-1 and 50-2 so that the switch 30 is turned off and the output signal of the mixer 20 is output to the amplifier 60. The process of measuring the impulse response of is executed. That is, the control unit 810 generates an impulse signal in the noise generator, radiates sound corresponding to the impulse signal to the adjustment target speaker, and performs FFT on the output signal of the microphone 90 to calculate the frequency response of the impulse response. It is. The second feature of the acoustic adjustment method according to the present embodiment is the arrangement of the adjustment target speaker and the microphone 90 in the spatial influence component specifying step SA120.

  FIG. 7 is a diagram illustrating an example of an arrangement mode of the adjustment target speaker and the microphone 90 in the spatial influence component specifying step SA120. More specifically, FIG. 7A is a perspective view of the acoustic space 2 viewed from the left side, and FIG. 7B is a perspective view of the acoustic space 2 viewed from above. As is clear from FIG. 7A and FIG. 7B, in the spatial influence component specifying step SA120, the adjustment target speaker (speaker 70-1) is the target except for the distance relationship with the microphone 90. They are arranged in the acoustic space 2 in the same manner as in the characteristic acquisition step SA110. That is, the adjustment target speaker is disposed in a hollow state suspended from the upper surface of the acoustic space 2 so as to be away from any of the surfaces of the acoustic space 2. On the other hand, the microphone 90 is located at a far position within the service area SA of the adjustment target speaker arranged as described above (in this operation example, a position separated from the adjustment target speaker by a distance L2 (L2> critical distance> L1)). Arranged coaxially with the speaker to be adjusted. As described above, in the spatial influence component specifying step SA120, the influence caused by the spatial characteristics of the entire acoustic space 2 (that is, the influence of reflected sound from each surface that can be a sound reflecting surface in the acoustic space 2) is specified. Because the purpose is to do.

  Also in this spatial influence component specifying step SA120, as in the target characteristic acquisition step SA110 described above, the acoustic engineer can use a plurality of different directions (front direction, ± 20 °, ± 40 °) from the adjustment target speaker. The microphone 90 is arranged at a position separated by a distance L2 in the direction in which the angle is formed, and the control unit 810 calculates the frequency response of the impulse response for each of these positions. On the other hand, in addition to each frequency response, control unit 810 determines the cross-correlation value between the frequency response of the impulse signal (input signal given to speaker 70-1) and the frequency response of the impulse response for each of the plurality of positions. Further, an average of frequency responses of the impulse responses is calculated. Then, the control unit 810 displays the frequency response graph of each impulse response and the cross correlation value graph on the display unit 840 in pairs for each position while matching the frequency axes, and The sound engineer is allowed to designate a frequency band (hereinafter referred to as a comparison target band) in which a difference between the average and the target characteristic is to be calculated.

  The acoustic engineer refers to the display content of the display unit 840 of the acoustic adjustment support device 80 and designates the comparison target band in the following manner. First, the acoustic engineer refers to the graph of the cross-correlation coefficient calculated for each of the plurality of positions, and the frequency at which the correlation between the frequency response of the impulse response and the frequency response of the impulse signal is maintained above a certain level. Pay attention to the bandwidth. Next, the acoustic engineer refers to the graph of the frequency response of the impulse response at each of the plurality of positions, compares the local change mode in the frequency band of interest, and the frequency in which the local change mode is common. Specify the band as the comparison target band. For example, in the example shown in FIG. 8A, the frequency response calculated from the impulse responses measured at each of four positions (positions separated from the adjustment target speaker by a distance L2) P1 to P4 in the service area SA. The graph FR and the graph of the cross-correlation coefficient coh are shown, and the comparison target bands designated as described above are shown by shading.

  When the comparison target band is designated as described above, the control unit 810 calculates the average of each frequency response obtained from the impulse response at each of the plurality of positions, and further, the target characteristic data in the comparison target band. The difference between the target characteristic indicated by and the average is calculated. Then, the control unit 810 displays the graph TFR indicating the target characteristics, the graph MFR indicating the average, and the graph DEF indicating the difference on the display unit 840 with the frequency axes matched (see FIG. 8B). The data representing the difference is written into the nonvolatile storage unit 854 as the spatial influence component data representing the spatial influence component. That is, the acoustic adjustment support device 80 according to the present embodiment displays the frequency response graph FR obtained from the impulse response and the cross-correlation value graph coh on the display unit 840 in pairs for each position (FIG. 8 ( By referring to A), the acoustic engineer supports the designation of the comparison target band, and calculates the spatial influence component based on the designation result. In addition, the acoustic engineer can grasp the spatial influence component from the three graphs (see FIG. 8B) displayed on the display unit 840. In this embodiment, the acoustic engineer designates the comparison target band, but the same criterion (in the frequency band where the correlation between the frequency response of the impulse response and the frequency response of the impulse signal is maintained at a certain level or more) Of course, the control unit 810 may execute processing for determining a comparison target band in accordance with a frequency band in which local changes in the frequency response of each impulse response are common.

  Next, the position influence component specifying step SA130 will be described. As described above, the position influence component specifying step SA130 is a step for specifying a position influence component. In the present embodiment, the microphone 90 is arranged at each of a plurality of different positions selected from positions far away from the adjustment target speaker in the service area of the adjustment target speaker or positions close to the adjustment target speaker in the service area. An impulse signal is measured in any of the impulse responses measured at each of the plurality of positions among the difference between the average frequency response calculated from each of the impulse responses and the target characteristic indicated by the target characteristic data. The difference between the frequency response and the impulse response is a frequency band in which the correlation between the frequency response and the frequency response of each impulse response is high, and the difference in the frequency band in which the local variation in the frequency response of each impulse response is common. This is for the same reason as redefining the spatial influence component. In the new definition of the position-influence component, the microphones 90 are placed at a plurality of different positions selected from a distant position in the service area of the adjustment target speaker or a position near the adjustment target speaker in the service area. The reason for arranging and measuring the impulse response is to prevent the influence from being reflected in either the direct sound or the reflected sound (indirect sound) from each surface.

  The position influence component redefined as described above is calculated in the following manner. First, the acoustic engineer arranges the speaker to be adjusted (that is, the speaker 70-1) and the microphone 90 at a predetermined position in the acoustic space 2, and operates the operation unit 830 to perform the position influence component identification support process. An execution instruction is given to the acoustic adjustment support device 80. The control unit 810 turns off the switch 30 and outputs the output signal of the mixer 20 to the amplifier 60 in the same manner as when the execution instruction of the target characteristic acquisition process (or the spatial influence component identification support process) is given. The selectors 50-1 and 50-2 are switched to execute processing for measuring the impulse response of the speaker to be adjusted.

  A third feature of the acoustic adjustment method according to the present embodiment is the arrangement of the adjustment target speaker and the microphone 90 in the position influence component specifying step SA130. FIG. 9 is a diagram illustrating an example of an arrangement mode of the adjustment target speaker and the microphone 90 in the position influence component specifying step SA130. More specifically, FIG. 9A is a perspective view of the acoustic space 2 viewed from the left side, and FIG. 9B is a perspective view of the acoustic space 2 viewed from above. The arrangement position of the speaker 70-1 in the position influence component specifying step SA130 is the original installation position in the acoustic space 2 (specifically, the right sleeve side of the stage 2A). In the position influence component specifying step SA130, when the adjustment target speaker is installed at the original position, the local situation in the vicinity of the installation position (if the adjustment target speaker is installed near the wall, the shape of the wall is determined. This is because it is intended to specify the influence (that is, the influence of the reflected sound from the reflecting surface in the vicinity of the installation position of the adjustment target speaker). On the other hand, the microphone 90 is arranged at a passenger seat position in the service area SA of the speaker 70-1 installed as described above. In the present embodiment, as shown in FIG. 9B, each of the four passenger seat positions M-1 to M-4, which are positions within the service area SA and have different distances and directions from the speaker 70-1, are provided. A microphone 90 is arranged, and impulse responses are measured at each of the four seat positions.

  Thereafter, the control unit 810 matches the frequency axis of the frequency response graph FR calculated from the impulse response measured at each position and the cross-correlation value graph coh in the same manner as in the spatial influence component identification support processing. While making it a pair for every position, it displays on the display part 840 (refer FIG. 10), and makes an acoustic engineer specify the comparison object zone | band. On the other hand, as in the case of the spatial influence component specifying step SA120, the acoustic engineer takes a correlation between the frequency response of the impulse signal and the frequency response of the impulse response, and a local change in the frequency response calculated from each impulse response. Based on this, the comparison target band is specified. In the example shown in FIG. 10, the frequency band designated as the comparison target band is shaded. Then, when the comparison target band is designated as described above, the control unit 810 calculates a difference between the target characteristic indicated by the target characteristic data in the comparison target band and the average of the frequency responses of the impulse responses, The graph indicating the target characteristics, the graph indicating the average, and the graph indicating the difference are displayed on the display unit 840 with the frequency axes matched, and the data indicating the difference is nonvolatile as the position influence component data indicating the position influence component Write to the storage unit 854.

  That is, the acoustic adjustment support device 80 according to the present embodiment displays the impulse response frequency response graph and the cross-correlation value graph coh on the display unit 840 in pairs for each position while matching the frequency axes. Thus, the acoustic engineer supports the designation of the comparison target band and calculates the position-influence component based on the designation result. In addition, the acoustic engineer obtains a position-influence component from the above three graphs displayed on the display unit 840 (a graph indicating the target characteristics, a graph indicating the average frequency response of each impulse response, and a graph indicating the difference between the two). Can be grasped. In addition, regarding the designation of the comparison target band in the specification of the position-influence component, the determination standard by the acoustic engineer (the frequency band in which the correlation between the frequency response of the impulse response and the frequency response of the impulse signal is maintained above a certain level) In addition, the control unit 810 may be made to execute based on the same standard as that of the frequency band in which the local change mode in the frequency response of each impulse response is common.

  In the filter coefficient calculation step SA140 executed subsequent to the position influence component specifying step SA130, the acoustic engineer operates the operation unit 830 to instruct the control unit 810 to execute the filter coefficient calculation process. In this filter coefficient calculation process, the control unit 810 eliminates each of the spatial influence component identified in the spatial influence component identification step SA120 and the positional influence component identified in the positional influence component identification step SA130. The coefficient is calculated based on the spatial influence component data and the position influence component data, and is set in the FIR filter 40. For example, the center frequency of each tap, the amplification level, and the steepness of amplification are adjusted so that the difference graph represented by each of the spatial influence component data and the position influence component data is combined by inverting the sign. Then, the filter coefficient is calculated, and the filter coefficient is set in the FIR filter 40.

  FIG. 11 is a diagram in which a graph TFR of target characteristics and a graph of frequency response calculated from the impulse response of the speaker to be adjusted (speaker 70-1) are drawn. In FIG. 11A, a frequency response graph FR in a state before the execution of the filter coefficient calculation step SA140 of this acoustic adjustment method is drawn together with a graph TFR of the target characteristic, and FIG. The graph FR ′ of the frequency response in the state after execution is drawn together with the graph TFR of the target characteristic. As apparent from FIGS. 11A and 11B, by executing this acoustic adjustment method, the target response and the frequency response of the impulse response actually measured in the frequency band from 20 Hz to 200 Hz are obtained. It can be seen that the improvement has been made to reduce the deviation. Further, in the present embodiment, since the FIR filter is used as a filter for realizing the acoustic adjustment, there is an advantage that a problem in the phase characteristic is less likely to occur compared to the case where the IIR filter is used.

  In the filter coefficient calculation step SA140, it is not always necessary to calculate the filter coefficient based on both the spatial influence component and the position influence component, and the filter coefficient may be calculated based on only one of them. Of course it is good. For example, if it is determined from the difference graph displayed on the display unit 840 in the spatial influence component specifying step SA120 that the spatial influence component is negligibly small, the acoustic engineer determines the position in the filter coefficient calculation step SA140. It is only necessary to operate the operation unit 830 and instruct the acoustic adjustment support device 80 to calculate the filter coefficient based only on the influence component data. Similarly, when it is grasped that the position influence component is small enough to be ignored, the acoustic engineer operates the operation unit 830 to calculate the filter coefficient based only on the spatial influence component data, and the acoustic adjustment support device 80 may be indicated. As described above, according to the present embodiment, when the speaker is installed in the acoustic space 2 and the sound is emitted, the spatial influence component and the position influence component are separately grasped, and the acoustic adjustment is independently performed for each component. It becomes possible to do.

(B: Other embodiments)
In the first embodiment described above, the case of performing the acoustic adjustment of the speakers installed on both sleeves of the stage 2A in the acoustic space 2 has been described. However, for example, the speaker is installed in a corner (a recessed corner portion) of the acoustic space. Speakers, speakers directly attached to the wall of the acoustic space (that is, speakers installed with a rigid wall behind), and installed with a shield such as a rib lattice or curtain in front. Of course, the present invention may be applied to the acoustic adjustment of a speaker.

(B-1: Application to the acoustic adjustment of the speaker installed in the corner of the acoustic space)
When a speaker is installed at the corner of the acoustic space, the sound in the low frequency range (specifically, 50 to 200 Hz) of the sound radiated from the speaker wraps behind the speaker housing, and the speaker is installed. It is reflected by the wall surface of the corner that is the position and heads toward the service area. For this reason, the frequency response calculated from the impulse response measured in the service area is generally higher in the intensity of the low frequency range than the target characteristic. Hereinafter, with reference to FIG. 12 to FIG. 16, an effect when the present invention is applied to the acoustic adjustment of the speaker installed at the corner of the acoustic space (that is, elimination of the difference from the target characteristic in the low frequency range). explain.

  FIGS. 12, 13 and 14 are diagrams for explaining the effect when the present invention is applied to the acoustic adjustment of a speaker installed in the corner of an acoustic space having a different size. More specifically, the acoustic space in the example shown in FIG. 12 is the widest (specifically, the auditorium between the 500-seat flat soil), and then the acoustic space in the example shown in FIG. 13 is wide (accommodating about 200 people). ), The acoustic space in the example shown in FIG. 14 is the narrowest (specifically, a conference room with about 10 accommodating persons). In the examples shown in FIGS. 12 to 14, the correction of the spatial influence component is omitted, and only the position influence component is corrected.

  In the example shown in FIG. 12, the microphones 90 are installed at eight different points in the service area of the speaker to be adjusted in the position influence component specifying step SA130 described above, and the impulse response at each point is measured to identify the position influence component. The correction was made. As can be seen from FIG. 12, the difference from the target characteristic is eliminated over the entire adjustment target band. The band to be adjusted is a frequency band in which the amplitude level is adjusted by correcting the position-influence component, and unless the frequency component is excluded due to a small difference from the target characteristic, the position-influence It matches the comparison target band specified in the component specifying step SA130.

  In the example shown in FIG. 13, the microphones 90 are installed at four different points in the service area of the adjustment target speaker in the position influence component specifying step SA130, and the impulse response at each point is measured to identify the position influence component. Correction was performed. In the example shown in FIG. 13, among the frequency components belonging to the adjustment target band, the frequency components indicated by the circles in the adjusted graph remain slightly different from the target characteristics, but the other frequency components are the target characteristics. The difference with is almost eliminated. Compared to the example shown in FIG. 12, in the example shown in FIG. 13, the number of measurement points of the impulse response is smaller. Therefore, if the number of impulse response measurement points is increased (for example, eight points are used in the same manner as in the example shown in FIG. 12), the frequency components with circles in the adjusted graph of FIG. It is considered that the difference between the two can be reduced. In addition, in the example shown in FIG. 13, a deviation from the target characteristic is recognized on the higher frequency side than the frequency band to be corrected. This is a reflection sound of a specific part from other than the corner in the vicinity of the speaker installation position. This is due to the fact that the control is independent of both the spatial influence component and the position influence component and cannot be controlled (frequency band where the cross-correlation value is extremely low).

  In the example shown in FIG. 14, the microphones 90 are installed at five different points in the service area of the adjustment target speaker in the position influence component specifying step SA130, the impulse response at each of these points is measured, and the position influence component is specified. Correction was performed. In the example shown in FIG. 14, among the frequency components belonging to the frequency band to be corrected, the difference from the target characteristic remains slightly for the frequency components indicated by the circles in the adjusted graph, but for the other frequency components The difference from the target characteristic is almost eliminated. In the adjusted graph of FIG. 14, the difference given a circle is due to hum noise (in other words, unrelated to the position influence component). Therefore, also in the example shown in FIG. 14, it is considered that the position-influencing component is sufficiently eliminated in the difference from the target characteristic.

  As described above, if the present invention is applied to the acoustic adjustment of the speaker installed in the corner of the acoustic space, the reflected sound from the wall surface that constitutes the corner is regardless of the width of the acoustic space. It is possible to appropriately suppress the resulting increase in the low frequency range and eliminate the difference from the target characteristic in the low frequency range.

  15 and 16 show that the acoustic space where the speaker is installed is a space where acoustic considerations are not taken, for example, in a warehouse, and is used for the acoustic adjustment of the speaker installed in the corner of the acoustic space. It is a figure for demonstrating the effect at the time of applying invention. The example shown in FIG. 15 differs from the example shown in FIG. 16 in the type of speaker to be adjusted, and there are four impulse response measurement points in each. As can be seen from FIGS. 15 and 16, although the influence of the reflected sound from the part other than the entrance corner remains outside the adjustment target band, the difference from the target characteristic is almost eliminated in the adjustment target band. . That is, if the present invention is applied to the acoustic adjustment of the speaker installed in the corner of the acoustic space, even if the acoustic space is a space where acoustic considerations are not paid, such as a warehouse, the corner It is possible to appropriately suppress the increase in the low frequency range caused by the reflected sound from the walls that make up the sound, eliminate the difference from the target characteristics in the low frequency range, and the same effect regardless of the type of speaker installed Is obtained.

(B-2: Application to acoustic adjustment of a speaker installed in an acoustic space with a rigid wall behind)
When a speaker is installed in an acoustic space with a rigid wall behind, the intensity of the low frequency range in the frequency response of the impulse response increases as in the case where it is installed in the corner of the corner, and there is a deviation from the target characteristic. May occur. FIG. 17 is a diagram for explaining the effect when the present invention is applied to the acoustic adjustment of the speaker installed in the acoustic space with the rigid wall behind. In the example shown in FIG. 17, a speaker is directly attached to the wall surface of the acoustic space in the example shown in FIG. In FIG. 17, an average graph of frequency responses and a graph of target characteristics calculated from impulsive responses measured at four different points in the service area of the speaker are shown before and after execution of acoustic adjustment. Has been. As can be seen from FIG. 17, although the influence of the reflected sound remains slightly higher than the adjustment target band, the difference from the target characteristic is almost eliminated in the adjustment target band. As described above, with respect to the speaker installed in the acoustic space with the rigid wall behind, by applying the present invention to the acoustic adjustment of the speaker, the enhancement of the bass range is appropriately suppressed, and the target characteristic in the bass range is achieved. It is possible to eliminate the difference.

(B-3: Application to acoustic adjustment of a speaker installed at the corner of an acoustic space and having a shield placed on the front)
FIG. 18 illustrates the effect of applying the present invention to the acoustic adjustment of a speaker that is installed at the corner of the acoustic space and that has a shield (in the example shown in FIG. 18, a rib lattice) in front. FIG. As shown in FIG. 18, in the state before adjustment, the influence caused by the installation of the speaker at the corner of the corner appears in the low frequency range of 50 to 100 Hz, and in the high frequency range of 2 kHz or higher, the rib lattice The impact of the installation of the. For this reason, in the example shown in FIG. 18, each of the said low sound range and a high sound range is made into the adjustment object band. As is apparent from the state after adjustment shown in FIG. 18, it can be seen that the difference from the target characteristic is almost eliminated in any of the two adjustment target bands. Thus, with respect to the speaker installed at the corner of the acoustic space with the shield placed on the front, by applying the present invention to the acoustic adjustment of the speaker, Therefore, it is possible to appropriately suppress the enhancement of the low range due to the reflected sound and the enhancement of the high range due to the shielding object, and to eliminate the difference from the target characteristic in both ranges.

(C: deformation)
Although each embodiment of the present invention has been described above, the following modifications may be added.
(1) In the above-described embodiment, the microphone 90 dedicated to acoustic adjustment is connected to the acoustic adjustment support device 80, but it is of course possible to perform acoustic adjustment using a microphone included in the sound source group 10. Further, in the above-described embodiment, the case where two speakers are installed in the acoustic space 2 has been described. However, three or more speakers may be installed in the acoustic space 2, and only one speaker is installed in the acoustic space 2. Of course, it is possible to install it. In the above-described embodiment, sound adjustment is performed using a speaker installed in the acoustic space 2. However, if the speaker is already fixed at a predetermined position in the acoustic space 2 and it is difficult to remove the speaker, sound adjustment may be performed using a speaker of the same model as the speaker. In the first embodiment described above, the same horizontal plane as the adjustment target speaker is used when measuring the impulse response of the adjustment target speaker in each of the target characteristic acquisition step SA110, the spatial influence component specification step SA120, and the position influence component specification step SA130. A microphone 90 was placed on the top. This reflects the fact that the audience seat group 2B in which the listener is seated in the acoustic space 2 spreads on a plane. Therefore, when the audience seat group is three-dimensionally arranged in the acoustic space 2 (for example, when the second-floor seat or the third-floor seat is provided), the impulse response measurement point (that is, the microphone 90) A plurality of (positioning positions) may be set in the vertical direction.

(2) In the above-described embodiment, the target characteristic acquisition step SA110 for acquiring the target characteristic is performed prior to the specification of the spatial influence component and the position influence component. However, when the speaker is shipped from the factory, the original impulse response of the speaker is measured in an anechoic room (or a simple anechoic room), and a CD-ROM (Compact Disk-Read Only Memory), Memory Stick (registered trademark), etc. Data indicating the impulse response (or the frequency response calculated from the impulse response) may be written and distributed on the computer-readable recording medium. By connecting the recording medium distributed in this way to the acoustic adjustment support device 80 and causing the control unit 810 to execute the process of writing the data as target characteristic data in the nonvolatile storage unit 854, the target characteristic acquisition step. Execution of SA110 can be omitted. Further, in the above-described embodiment, the position influence component is specified after the spatial influence component is specified. However, the position influence component may be specified first.

(3) In the spatial influence component specifying step SA120 of the above-described embodiment, the microphones 90 are arranged at a plurality of positions in the service area of the adjustment target speaker held away from any of the sound reflection surfaces in the acoustic space. Then, the impulse response was measured for each arrangement position to identify the spatial influence component. However, it is also possible to measure the impulse response only at a distant location in the service area and calculate the spatial influence component from the impulse response. Specifically, the frequency response calculated from the impulse response measured at one distant location in the service area is compared with the frequency response calculated from the impulse signal, and the frequency band having a high correlation between the two is compared. And Of the difference between the frequency response calculated from the impulse response and the target characteristic, the difference in the comparison target band is used as the spatial influence component. According to such an aspect, although there is a disadvantage that high specific accuracy cannot be obtained compared to an aspect in which a spatial influence component is specified based on impulse responses measured at a plurality of positions in the service area, it is easy. There is an advantage that a spatial influence component can be specified. Similarly, for the position-influencing component, the impulsive response is measured only at a distant or nearby location in the service area of the speaker installed at a predetermined position in the acoustic space, and the position-influencing component is calculated from the impulsive response. You may make it do.

(4) In the above-described embodiment, the control unit 810 of the acoustic adjustment support device 80 executes the target characteristic acquisition support processing, the spatial influence component identification support processing, and the position influence component specification support processing that clearly show the features of the present invention. The acoustic adjustment support program is stored in the nonvolatile storage unit 854 in advance. However, the acoustic adjustment support program may be written and distributed on a computer-readable recording medium such as a CD-ROM, or the acoustic adjustment support program may be distributed by downloading via a telecommunication line such as the Internet. good. The acoustic adjustment support program distributed in this way is installed in a general computer, and the computer unit functions as the acoustic adjustment support device of the present embodiment by operating the control unit according to the acoustic adjustment support program. It is because it becomes possible to make it.

  DESCRIPTION OF SYMBOLS 1 ... Acoustic system, 2 ... Acoustic space, 2A ... Stage, 2B ... Audience seat group, 10 ... Sound source group, 20 ... Mixer, 30 ... Switch, 40 ... FIR filter, 50-1, 50-2 ... Selector, 60 ... Amplifier, 70-1, 70-2 ... Speaker, 80 ... Acoustic adjustment support device, 90 ... Microphone, 810 ... Control unit, 820 ... External device I / F group, 830 ... Operation unit, 840 ... Display unit, 850 ... Memory Part, 852 ... volatile memory part, 854 ... nonvolatile memory part, 860 ... bus.

Claims (5)

An acoustic adjustment support method for adjusting a frequency response in a sound space of a sound radiated from the speaker by adjusting a setting of a filter disposed in a front stage of the speaker installed at a predetermined position in the acoustic space. And
A frequency response including the influence of the reflecting surface is measured for the speaker by using a microphone that is placed far away in the service area while holding the speaker in the acoustic space away from the sound reflecting surface of the acoustic space. Of the difference between the measured frequency response and the target characteristic which is the frequency response of the speaker that does not include the influence of the reflecting surface, the frequency between the input signal applied to the speaker and the output signal of the microphone is high A spatial influence component specifying step for specifying a difference in a band as a spatial influence component reflecting an influence caused by a spatial characteristic of the entire acoustic space;
The speaker is installed at the predetermined position, and a frequency response including the influence of the reflecting surface near the installation position is measured with respect to the speaker by using a microphone disposed far away or in the vicinity of the service area. Of the difference from the target characteristic, the difference in the frequency band in which the correlation between the input signal applied to the speaker and the output signal of the microphone is high, and the position effect reflecting the influence caused by the local situation in the vicinity of the installation position A position-influence component identifying step that identifies the component;
A filter setting adjustment step for adjusting the setting of the filter so that at least one of the spatial influence component and the position influence component is eliminated;
An acoustic adjustment support method characterized by comprising: In the spatial influence component specifying step, a frequency including the influence of the reflection surface by disposing the microphones at a plurality of positions in the service area of the speaker held away from the reflection surface of the sound in the acoustic space. The response is measured for each microphone placement position, and the difference between the average of the frequency response and the target characteristic is a frequency band in which the correlation between the input signal applied to the speaker and the output signal of the microphone is high, And the difference in the frequency band with which the local fluctuation | variation aspect is common in each said frequency response is specified as said space influence component,
In the position influence component specifying step, microphones are arranged at a plurality of positions far away or in the vicinity of the service area of the speaker installed at the predetermined position, and the influence of the reflection surface near the speaker installation position is included. The frequency response is measured for each microphone placement position, and the difference between the average of the frequency response and the target characteristic is a frequency band in which the correlation between the input signal applied to the speaker and the output signal of the microphone is high. And the difference in the frequency band with which the local fluctuation | variation aspect is common in each said frequency response is specified as said position influence component. The acoustic adjustment assistance method of Claim 1 characterized by the above-mentioned.   The speaker is fixed at a predetermined position in the acoustic space. In the spatial influence component specifying step, the speaker of the same model as the speaker is held away from the sound reflection surface of the acoustic space in place of the speaker. The acoustic adjustment support method according to claim 1, wherein the spatial influence component is specified. An acoustic adjustment that assists in adjusting the frequency response in the acoustic space of the sound radiated from the speaker by adjusting the setting of a filter arranged in front of the speaker installed at a predetermined position in the acoustic space A support device,
An input signal is given to the speaker held away from the sound reflection surface of the acoustic space, and a frequency response including the influence of the reflection surface on the speaker from an output signal of a microphone arranged far away in the service area And calculating a difference between the frequency response and a target characteristic that is a frequency response of the speaker that does not include the influence of the reflecting surface, and the input signal given to the speaker among the difference and the Spatial effect that performs processing for assisting the user to specify the difference in the frequency band highly correlated with the output signal of the microphone as a spatial influence component reflecting the effect caused by the spatial characteristics of the entire acoustic space. Component identification support means,
An input signal is given to the speaker installed at the predetermined position, and a frequency response including the influence of a reflection surface near the installation position is applied to the speaker from an output signal of a microphone arranged far away or in the vicinity of the service area. And calculating the difference between the frequency response and the target characteristic, and calculating the difference in the frequency band in which the correlation between the input signal applied to the speaker and the output signal of the microphone is high. A position-influence component specifying means for executing a process for supporting the user to specify as a position-influence component reflecting an influence caused by a local situation in the vicinity of the installation position;
Filter setting adjustment means for adjusting the setting of the filter so that at least one of the spatial influence component and the position influence component is eliminated;
An acoustic adjustment support device comprising: Computer
A speaker installed at a predetermined position in the acoustic space, which gives an input signal to the speaker held away from the sound reflecting surface of the acoustic space, and an output of a microphone disposed far away in the service area A process of calculating a frequency response including the influence of the reflection surface for the speaker from a signal and calculating a difference between the frequency response and a target characteristic which is a frequency response of the speaker not including the influence of the reflection surface Among the differences, the difference in the frequency band in which the correlation between the input signal applied to the speaker and the output signal of the microphone is high is used as a spatial influence component that reflects the influence caused by the spatial characteristics of the entire acoustic space. A spatial influence component identification support means for executing a process for supporting the identification by the user;
An input signal is given to the speaker installed at the predetermined position, and a frequency response including the influence of a reflection surface near the installation position is applied to the speaker from an output signal of a microphone arranged far away or in the vicinity of the service area. And calculating a difference between the frequency response and the target characteristic, and calculating a difference in a frequency band in which a correlation between an input signal applied to the speaker and an output signal of the microphone is high from the difference. A position influence component specifying means for executing a process for supporting the user to specify as a position influence component reflecting an influence caused by a local situation in the vicinity;
A filter setting adjusting means for adjusting a setting of a filter installed in a front stage of the speaker so that at least one of the spatial influence component and the position influence component is eliminated;
A program characterized by functioning as

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