JP2008227680A - Acoustic characteristic correction system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acoustic characteristic correction system for effectively attaining acoustic characteristics without giving an unpleasant feeling to a user. <P>SOLUTION: In the acoustic characteristic correction system, emitted sound from a speaker 15 is collected by a microphone 16 and present acoustic characteristics 254 are acquired. A CPU 11 individually sets an enhancing correction frequency range for performing correction in an enhancement direction and a suppression correction frequency range for performing the correction in a suppressing direction. In the acoustic characteristics 254, there are peaks 273 and 272 and dips 271 and 274. The CPU 11 detects the partial frequency bands of the dips 271 and 274, corrects only the dip 271 in the enhancement correction frequency range in the enhancement direction and does not corrects the dip 274 which is not in the enhancement direction correction frequency range in the enhancement direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a frequency characteristic correction system that measures a transmission characteristic from a speaker to a listener position and corrects it to a desired characteristic.

Currently, there are various environments where ordinary people can easily enjoy music. One example is a karaoke box. In a karaoke box, a microphone used by a singer and a speaker that emits sound collected by a microphone, music sound of a karaoke performance, and the like are installed in a closed space that is not so large. In such an environment, there is an acoustic characteristic that is unique to the environment and may have an acoustic characteristic that is not preferred by the user. In such an environment, a closed loop of sound transmission is formed, and the signal level in a specific frequency band becomes extremely high, and howling may occur. For these problems, an equalizer is installed in a karaoke apparatus or the like, and the acoustic characteristics are corrected by the equalizer. For example, Patent Document 1 sets an equalizer so as to attenuate a signal level in a frequency band that is howling, and Patent Document 2 performs correction of audio characteristics, but the characteristics after correction are extreme. The correction level and the correction frequency band are appropriately set by the operator so as not to become a problem.
JP-A-8-84394 Japanese Unexamined Patent Publication No. 7-38988

  However, the above-mentioned acoustic characteristic correction system realizes a detailed and simple acoustic characteristic that satisfies the user, such as only reducing the signal level or uniquely setting the correction frequency range and limit value. That was not easy.

  Therefore, an object of the present invention is to provide an acoustic characteristic correction system that can effectively realize an acoustic characteristic that does not cause discomfort to the user.

  The present invention relates to an acoustic characteristic correction system that corrects an acoustic characteristic of a system in which sound emitted from a speaker is propagated to a microphone position in a predetermined space where a microphone and a speaker are installed, to a desired acoustic characteristic. . The acoustic characteristic correction system according to the present invention includes an equalizing means for performing correction by dividing a sound pickup signal of a microphone into a plurality of frequency band components and giving adjustment of a predetermined frequency characteristic to each frequency band component, and the equalizing Correction characteristic calculating means for calculating a correction characteristic for causing the means to execute correction. Then, the correction characteristic calculation means of the acoustic characteristic correction system according to the present invention individually sets the enhancement direction correction frequency range for performing correction for increasing the signal level and the suppression direction correction frequency range for performing correction for decreasing the signal level. It is characterized by.

  In this configuration, the acoustic characteristics are corrected by dividing the sound pickup signal of the microphone into a plurality of frequency bands by the equalizing means and adjusting the signal level of each frequency band component. At this time, the adjustment of the signal level includes a correction for increasing the signal level (enhancement correction) and a correction for reducing the signal level (suppression correction). In the acoustic characteristic correction system of the present invention, The frequency range for performing the suppression correction is set differently. With this setting, for example, it is possible to make a detailed setting such that the enhancement correction can be prohibited in a frequency band where the suppression correction is necessary but the enhancement correction should not be performed.

  In the acoustic characteristic correction system according to the present invention, the correction characteristic calculation means sets the high side threshold frequency of the enhancement direction correction frequency range to be lower than the high side threshold frequency of the suppression direction correction frequency range. .

  In this configuration, the high frequency component is unnecessarily enhanced by lowering the high frequency threshold frequency of the frequency range where the enhancement correction is performed than the high frequency threshold frequency of the frequency range where the suppression correction is performed. This can be prevented.

  In the acoustic characteristic correction system according to the present invention, the correction characteristic calculation means sets the high frequency side threshold frequency of the enhancement direction correction frequency range based on the high frequency attenuation characteristic of the sound emission characteristic of the speaker. .

  In this configuration, the high-frequency threshold frequency for the enhancement correction is set according to the sound emission characteristics of the speaker, that is, the output level of the frequency component equal to or higher than the predetermined frequency determined by the speaker specification. As a result, it is possible to prevent an unreasonable level increase in the frequency band higher than the high-frequency threshold frequency that is difficult to be output from the speaker.

  In the acoustic characteristic correction system of the present invention, the correction characteristic calculation means sets the lower threshold frequency of the enhancement direction correction frequency range to be higher than the lower threshold frequency of the suppression direction correction frequency range. .

  In this configuration, the low frequency component is unnecessarily enhanced by setting the low frequency threshold frequency of the frequency range in which the enhancement correction is performed to be lower than the low frequency threshold frequency of the frequency range in which the suppression correction is performed. This can be prevented.

  In the acoustic characteristic correction system according to the present invention, the correction characteristic calculation means sets the lower threshold frequency of the enhancement direction correction frequency range based on the sound emission characteristic of the speaker and the low-frequency attenuation characteristic of the sound collection characteristic of the microphone. It is characterized by doing.

  In this configuration, the sound output characteristic of the speaker, that is, the output level of the frequency component below the predetermined frequency determined by the speaker specification is reduced, or the sound collection characteristic of the microphone, that is, the frequency below the frequency determined by the microphone specification. In accordance with the decrease in the input level of the frequency component, the low frequency side threshold frequency for the enhancement correction is set. As a result, it is possible to prevent an unreasonable level from being raised in the lower frequency band than the lower frequency threshold frequency, which is difficult to output from the speaker.

  According to the present invention, the frequency band to be corrected can be individually set according to the direction of correction of the signal level such as enhancement / suppression, so that more appropriate correction is possible and comfortable for the user. The acoustic characteristics can be corrected in detail and easily.

An acoustic characteristic correction system according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of an acoustic characteristic correction system according to the present embodiment. FIG. 1A illustrates a configuration in an acoustic characteristic correction setting mode, and FIG. 1B illustrates a configuration in a normal use mode.
FIG. 2A is a block diagram showing the configuration of the characteristic measuring unit 22, and FIG. 2B is a diagram showing the concept of frequency band division.
FIG. 3 is a block diagram showing a configuration of the equalizing processing unit 12.
As shown in FIG. 1A, in the acoustic characteristic correction setting mode, the acoustic characteristic correction system of the present embodiment includes a CPU 11, an equalizing processing unit 12, a D / A converter 13, a power amplifier 14, a speaker 15, a microphone 16, An echo processing unit 17, an A / D converter 18, a test sound source 21, and a characteristic measurement unit 22 are provided.

  When the CPU 11 receives an input to start sound characteristic correction setting via an operation unit (not shown) or the like, the CPU 11 gives test sound generation start control to the test sound source 21. Upon receiving the test sound source generation start control, the test sound source 21 generates a preset signal or an acoustic characteristic measurement signal designated by the CPU 11, for example, a white noise signal or a pink noise signal. The D / A converter 13 converts the digital acoustic characteristic measurement signal into an analog signal and supplies it to the power amplifier 14. The power amplifier 14 amplifies the acoustic characteristic measurement signal with a predetermined amplification factor set in advance or specified by the CPU 11 and applies the amplified signal to the speaker 15. Sounds out. For example, when measuring the acoustic characteristics of a karaoke box, sound from an acoustic characteristic measurement signal is emitted from a speaker installed in the karaoke box.

  The microphone 16 is installed at a preset position in the same room as the speaker 15. For example, in a karaoke box, it is installed in a standing position where a singer usually stands. The microphone 16 collects the sound based on the acoustic characteristic measurement signal emitted from the speaker 15 and supplies the sound to the echo processing unit 17. The echo processing unit 17 adds a singer's favorite echo in the normal use mode described later, but outputs it to the A / D converter 18 without performing echo processing in the acoustic characteristic correction setting mode. The A / D converter 18 converts the sound picked up by the microphone 16 from an analog format to a digital format, and provides the characteristic measurement unit 22 with the sound.

  The characteristic measuring unit 22 detects the signal level of each of the partial frequency bands FB1 to FBm obtained by dividing the preset measurement frequency range FZ by a predetermined number m, and outputs the signal level to the CPU 11. Specifically, in the partial frequency bands FB1 to FBm, the measurement frequency range FZ corresponding to the frequency band to be measured set in advance from the speaker characteristics, the microphone characteristics, etc. is divided into m at equal frequency bands on the logarithmic axis, for example. It consists of a band and is set to FB1, FB2,... FBm in order from the low frequency side. The characteristic measurement unit 22 includes band pass filters (BPF) 221 and 222 to 22m corresponding to the number m of partial frequency bands, and signal level detection units 231 and 232 to 23m that detect signal levels of the partial frequency bands. . The BPF corresponding to each partial frequency band and the signal level detection unit are connected in series, and the series circuit of the BPF and signal level detection unit for each partial frequency band is connected in parallel. For example, specifically, the FB1 band BPF 221 for the first partial frequency band FB1 and the FB1 signal level detector 231 are connected in series to form an FB1 signal detection series circuit. Similarly, an FB2 band BPF 222 for the second partial frequency band FB2 and an FB2 signal level detection unit 232 are connected in series to form an FB2 signal detection series circuit, and an FBm band BPF 22m for the mth partial frequency band FBm. The FBm signal level detector 23m is connected in series to form an FBm signal detection series circuit. Such an FBm signal detection series circuit group is connected in parallel between the A / D converter 18 and the CPU 11. With such a configuration, the collected sound signal input from the A / D converter 18 is decomposed into the respective band components by the respective BPFs 221 to 22m. The partial frequency band component signals generated by the respective BPFs 221 to 22m are subjected to level detection by the respective signal level detectors 231 to 23m, and this level value is output to the CPU 11 together with the partial frequency band information. In addition, the characteristic measurement unit 22 includes a full-band signal level detection unit 230 that detects a signal level in the measurement frequency range FZ. The all-band signal level detection unit 230 is connected in parallel with each series circuit, detects the signal level of the sound pickup signal input from the A / D converter 18, and outputs it to the CPU 11 as the original signal level value.

  The CPU 11 normalizes the level value of each partial frequency band component signal with the original signal level value. The CPU 11 compares the level value of the normalized partial frequency band signal (normalized partial band signal level) with the normalized desired acoustic characteristic preset and stored in a memory (not shown) in each partial frequency band. Then, the peak and dip for the desired acoustic characteristics are detected. Here, the peak indicates a portion where the normalized partial band signal level is higher than the desired acoustic characteristic, and the dip indicates a portion where the normalized partial band signal level is lower than the desired acoustic characteristic. Specifically, the CPU 11 performs a process of correcting these peaks and dips using a method described later. The CPU 11 sets the enhancement direction correction frequency range for enhancing the dip signal level and the suppression direction correction frequency range for suppressing the peak signal level, and calculates a correction value in accordance with each frequency range. CPU11 sets the correction parameter of each PEQ121-12n of the equalizing process part 12 based on the calculated correction value.

  The equalizing processing unit 12 is composed of PEQ multistage cascade connection, and in the example of FIG. 3, it is composed of n PEQs 121 to 12n cascade connection. Each of the PEQs 121 to 12n is given a correction parameter from the CPU 11, and performs an equalizing process using the correction parameter. Thereby, the equalizing process part 12 which correct | amends the acoustic characteristic of the room in which the speaker 15 and the microphone 16 were installed to a desired acoustic characteristic, and emits sound can be formed.

  After such setting, an apparatus having a circuit configuration as shown in FIG. 1B is used in actual use (normal mode). In the following description, a karaoke system with a karaoke box is shown. Since the system configuration of the karaoke system is known, a detailed description is omitted.

  As shown in FIG. 1B, in the normal use mode, the acoustic characteristic correction system of the present embodiment includes the CPU 11, the equalizing processing unit 12, the D / A converter 13, the power amplifier 14, the speaker 15, the microphone 16, and the echo processing. A unit 17, an A / D converter 18, a mixer 19, and a sound source 20 are provided.

  The sound source 20 is a known karaoke sound source, for example, and generates a digital music sound signal based on the music data of the karaoke music and outputs it to the mixer 19. The microphone 16 collects the singing sound of the singer and outputs a collected signal to the echo processing unit 17. The echo processing unit 17 performs echo processing on the collected sound signal in accordance with echo instruction contents separately set by a singer or the like, and outputs it to the A / D converter 18. The A / D converter 18 converts the collected sound signal after the echo processing into a digital format and outputs it to the mixer 19. The mixer 19 mixes the music sound signal and the collected sound signal after the echo processing to generate a sound emission signal, and outputs it to the equalizing processing unit 12.

  The equalizing processing unit 12 corrects the sound emission signal by each of the PEQs 121 to 12n set in the above-described acoustic characteristic correction mode, and outputs it to the D / A converter 13. The D / A converter 13 converts the sound emission signal (acoustic characteristic corrected sound emission signal) whose acoustic characteristics are corrected from a digital format to an analog format and outputs the converted signal to the power amplifier 14. The power amplifier 14 amplifies the acoustic characteristic corrected sound emission signal and applies the amplified sound characteristic signal to the speaker 15. The speaker 15 is driven based on the amplified acoustic characteristic correction sound emission signal and emits sound into the room. By using such a configuration, the music sound and the singing sound emitted from the speaker 15 are corrected to the desired acoustic characteristics and reach the singer holding the microphone 16. Thereby, the singer can sing in the karaoke box comfortably.

  Next, a specific acoustic characteristic correction method will be described with reference to FIGS.

FIG. 4 is a diagram showing a system flow of an acoustic characteristic correction method by the acoustic characteristic correction system.
In the acoustic characteristic correction system, when the acoustic characteristic correction setting mode is executed, the characteristic measurement unit 22 detects the level values of the band component signals of the partial frequency bands FB1 to FBm (S101). The CPU 11 calculates the difference between the level value of each band component signal and each band component signal level (desired signal level) of the desired acoustic characteristics, and the difference value, which is an absolute value, and the difference direction (“+” or “−”). Is calculated (S102). CPU11 detects the peak and dip of the frequency characteristic of a difference value sequence from the difference value and difference direction of each partial frequency band FB1-FBm (S103). That is, the CPU 11 extracts a maximum value on the high level side from the desired acoustic characteristics in the frequency characteristics of the difference value sequence and a minimum value on the low level side from the desired acoustic characteristics, and sets the partial frequency band for each maximum value and minimum value. Obtain by associating. Further, the CPU 11 sorts and stores each peak and dip in descending order from the higher difference value (absolute value) level (S104).

  The CPU 11 sets the counter to i = 1 (S105), acquires the first peak or dip, and detects whether it is a peak or a dip (S106). If it is a peak (S106: Peak), the CPU 11 calculates a correction value including a gain (− direction) and a Q value corresponding to the difference value level of the peak (S107), and updates the counter by +1 (S110).

  If it is a dip (S106: Dip), the CPU 11 detects whether or not the partial frequency band in which the dip exists is within the enhancement direction correction frequency range FBud (S108). If the dip is within the enhancement direction correction frequency range FBud (S108: Y), a correction value consisting of a gain (+ direction) and a Q value corresponding to the difference value level of the dip is calculated (S107), and the counter +1 is updated (S110). On the other hand, if the dip is outside the enhancement direction correction frequency range FBud (S108: N), the correction value is not calculated (S109), the dip is deleted from the sorted list, and the next peak is obtained. Alternatively, a dip correction value calculation process is executed (S114 → S106).

  At this time, the enhancement direction correction frequency range FBud and the suppression direction correction frequency range FBd set by the CPU 11 are set based on the output characteristics of the speaker 15 to be used. Specifically, the suppression direction correction frequency range FBd that can only correct the suppression direction is set in the output frequency range of the speaker 15, and the enhancement direction correction frequency range that allows bidirectional correction between the suppression direction and the enhancement direction. FBud is set in a frequency range in which the output of the speaker 15 is stable and has a substantially flat frequency characteristic. By performing such a setting, it is possible to prevent correction in an inappropriate enhancement direction. That is, the correction in the direction of significant enhancement in the vicinity of the high-frequency side end and the low-frequency side end of the low-output speaker output frequency region (frequency region that is in the suppression direction correction frequency range and not in the enhancement direction correction frequency range). Can be prevented. Thereby, clipping of the signal for sound emission in the circuit after the equalizing processing unit can be prevented, and an unpleasant emotion can be prevented from being given to the user (singer). In the frequency region that is in the suppression direction correction frequency range and not in the enhancement direction correction frequency range, the sound is actually emitted from at least the speaker 15. For this reason, when a peak exists in the frequency region, correction processing for suppressing the peak can be performed, so that more optimal acoustic characteristics can be realized while preventing clipping.

  When calculating the correction value, the CPU 11 updates the counter by +1 as described above, checks whether the counter is a predetermined value ns set in advance, and if the counter value has not reached ns, the next peak or A dip correction value calculation process is executed (S111: N → S106). By not counting the dip that is not corrected in this way, the resources of the equalizing processing unit can be used more effectively.

  The CPU 11 ends when such correction value calculation processing reaches the predetermined value ns (S111: Y), and generates a parameter list to be given to the equalizing processing unit 12 from the calculated correction value group (S112). Here, the parameter list indicates an initial parameter group of the PEQs 121 to 12n constituting the equalizing processing unit 12. That is, the set frequency (f), gain (G), and Q value of each PEQ are sequentially set based on each correction value and the corresponding partial frequency band FB, and a parameter list is set from these set parameter groups. It is formed. Based on the generated parameter list, the CPU 11 transmits initial parameters corresponding to the cascade-connected PEQs 121 to 12n of the equalizing processing unit 12 (S113). Each of the PEQs 121 to 12n of the equalizing processor 12 executes an equalizing process based on the given initial parameters. Thereby, the acoustic environment of the desired acoustic characteristic set beforehand is realizable in the room (system from a speaker to a microphone).

  Although not specified in the above description, the initial parameter setting process can be facilitated by detecting peaks and dips in each of the suppression direction correction frequency range FBd and the enhancement direction correction frequency range FBud. Can be.

Next, the above-described correction process is shown in the examples of FIGS.
5 to 7 are frequency characteristic diagrams for explaining the method and concept of acoustic characteristic correction. In each figure, (A) shows the normalized frequency characteristics 250, 252, and 254 of the collected sound signal when white noise is emitted from the speaker 15 and collected by the microphone 16, and (B) shows the sound collected signal. The concept of the peak and dip based on the frequency characteristics 250, 252 and 254 and the desired acoustic characteristic 260 set in advance is shown. (C) is a sound collection signal after the correction processing in the equalizing processing unit 12 (acoustic collection after acoustic characteristic correction). Sound frequency) 251, 253, 255 and desired acoustic characteristics 260 are shown. FIG. 5 shows a frequency region that overlaps the enhancement direction correction frequency range FBud that enhances the signal level of the dip and the suppression direction correction frequency range FBd that suppresses the peak signal level (equal to the above-described entire band FZ). Only a peak 272 and a dip 271 to be corrected are shown. FIG. 6 shows a case where there is a peak 273 to be corrected in the frequency region within the suppression direction correction frequency range FBd on the lower side of the enhancement direction correction frequency range FBud from the characteristics of FIG. FIG. 7 shows a case where there is a dip 274 that should not be corrected in the frequency region within the suppression direction correction frequency range FBd on the higher frequency side than the enhancement direction correction frequency range FBud from the characteristics of FIG.

(1) When there are a peak 272 and a dip 271 to be corrected only in a frequency region that overlaps between the enhancement direction correction frequency range FBud and the suppression direction correction frequency range FBd (in the case of FIG. 5)
When a frequency characteristic 250 (see FIG. 5A) having a peak 272 and a dip 271 in such a frequency range is detected, the CPU 11 detects the peak 272 and the dip 271 and has a large level value as described above. A peak 272 and a dip 271 are set in order. When the CPU 11 detects that the dip 271 is within the suppression direction correction frequency range FBd permitted to be corrected, the level is the same as the difference value between the peak 272 and the level of the desired acoustic characteristic of the corresponding partial frequency band of the dip 271. And the correction value (correction value in the direction shown by the arrow in FIG. 5B) consisting of the opposite sign is set. For example, for the peak 272, a correction value “−” is set as the correction in the direction to suppress, and for the dip 271, a correction value “+” is set as the correction in the direction to increase. Then, parameters to be given to each PEQ from these correction value groups are set and given to each PEQ. As a result, as shown in FIG. 5C, an acoustic characteristic 251 that is the same as the desired acoustic characteristic at least in a region where the output characteristic of the speaker 15 is flat and similar to the desired acoustic characteristic in the entire frequency range FBd (FZ). Can be realized.

(2) In addition to the situation of (1), a peak 273 exists in the frequency region in the suppression direction correction frequency range FBd on the lower side of the enhancement direction correction frequency range FBud (in the case of FIG. 6)
When the frequency characteristic 252 having the peaks 272, 273 and the dip 271 as shown in FIG. 6A is detected, the CPU 11 detects the peaks 272, 273 and the dip 271, and in order of increasing level value as described above. Peak 273, peak 272 and dip 271 are set. Then, the CPU 11 corrects the correction value (indicated by the arrow in FIG. 6B) at the same level as the difference value between the respective peak 273, peak 272, and dip 271 and the level of the desired acoustic characteristic in the corresponding partial frequency band. (Correction value in the direction shown in Fig. 1). For example, for the peak 273 and the peak 272, a correction value “−” is set as the correction in the direction to suppress, and the correction value “+” is set as the correction in the direction to enhance the dip 271. Then, parameters to be given to each PEQ from these correction value groups are set and given to each PEQ. As a result, it is possible to realize an acoustic characteristic 253 that is at least the same as the desired acoustic characteristic 260 in the region where the output characteristics of the speaker 15 are flat and that is more similar to the desired acoustic characteristic 260 in the entire frequency range FBd (FZ).

(3) In addition to the situation of (2), when a dip 274 exists in the frequency region within the suppression direction correction frequency range FBd on the higher frequency side than the enhancement direction correction frequency range FBud (in the case of FIG. 7)
When the frequency characteristic 254 having the peaks 272 and 273 and the dips 271 and 274 as shown in FIG. 7A is detected, the CPU 11 detects the peaks 272 and 273 and the dips 271, and the level value as described above. A dip 274, a peak 273, a peak 272, and a dip 271 are set in descending order. The CPU 11 determines whether or not the dips 274 and 271 exist within the enhancement direction correction frequency range FBud, and excludes the dips 274 that do not exist within the enhancement direction correction frequency range FBud from the correction target. Then, the CPU 11 corrects a correction value (indicated by an arrow in FIG. 7B) at the same level as the difference value between the respective peak 273, peak 272, and dip 271 and the level of the desired acoustic characteristic in the corresponding partial frequency band. (Correction value in the direction shown in Fig. 1). For example, for the peak 273 and the peak 272, a correction value “−” is set as the correction in the direction to suppress, and the correction value “+” is set as the correction in the direction to enhance the dip 271. Then, parameters to be given to each PEQ from these correction value groups are set and given to each PEQ. As a result, an acoustic characteristic 255 that is at least the same as the desired acoustic characteristic 260 in the region where the output characteristic of the speaker 15 is flat and that is more similar to the desired acoustic characteristic 260 in the entire frequency range FBd (FZ) can be realized.

  As described above, by using the system having the configuration of the present embodiment, it is possible to prevent correction in an inappropriate enhancement direction, and it is possible to prevent an unpleasant emotion from being given to the user (singer). Further, since the correction in the suppression direction can be performed while preventing the correction in the inappropriate enhancement direction, more optimal acoustic characteristics can be realized. Further, useless resources such as PEQ of the equalizing processing unit 12 can be prevented by correction in an inappropriate enhancement direction, and even a small amount of resources can be used effectively to realize desired acoustic characteristics.

  In the above description, the case of different components in each mode has been described. However, an acoustic characteristic correction system having the configurations of FIGS. 1A and 1B may be used. That is, a circuit switching unit such as a switch may be provided, and the acoustic characteristic correction setting mode and the normal use mode may be properly used by switching processing of the circuit switching unit.

  In the above description, the equalizing processing unit 12 is configured by the cascaded PEQ. However, an analog equalizer as shown in FIG. 8A or a graphic equalizer as shown in FIG. 8B is used. Also good.

FIG. 8 is a diagram illustrating another configuration example of the equalizing processing unit according to the present embodiment. FIG. 8A illustrates a configuration including an analog equalizer, and FIG. 8B illustrates a configuration including a graphic equalizer.
The equalizing processing unit shown in FIG. 8A includes a BPF for a partial frequency band that separates the collected sound signal into components of each partial frequency band, and a gain adjustment unit X (a switch and a resistor that can adjust the gain with a fixed Q). And a series circuit in parallel with the partial frequency band. On the other hand, the equalizing processing unit shown in FIG. 8B has a basic circuit of a so-called graphic equalizer. Note that when these circuits are used, an A / D converter or a D / A converter is not necessary in some cases and can be omitted.

  When the equalizing processing unit is configured by these circuits, gain adjustment for each partial frequency band of the signal is performed only when equalizing processing is performed. Since the number of stages in which sound quality deteriorates is reduced, in addition to the effects of the present invention described above, better sound quality can be obtained.

  In the above description, the sound collection characteristic of the microphone 16 is not particularly specified. However, by acquiring the sound collection characteristic of the microphone 16 in advance and giving it to the CPU 11, the CPU 11 can Correction parameters that take into account the sound collection characteristics can be set in the equalizing processing unit 12. Thereby, the acoustic characteristic by the system | strain from the speaker 15 to the singer who sings with the microphone 16 can be set to a desired characteristic, and the more suitable acoustic environment for a singer can be implement | achieved.

It is a block diagram which shows the structure of the acoustic characteristic correction system of this embodiment. It is a block diagram which shows the structure of the characteristic measurement part 22, and a figure which shows the division | segmentation concept of a frequency band. 3 is a block diagram showing a configuration of an equalizing processing unit 12. FIG. It is a figure which shows the system flow of the acoustic characteristic correction method by an acoustic characteristic correction system. It is a frequency characteristic diagram for demonstrating the method and concept of an acoustic characteristic correction | amendment. It is a frequency characteristic diagram for demonstrating the method and concept of an acoustic characteristic correction | amendment. It is a frequency characteristic diagram for demonstrating the method and concept of an acoustic characteristic correction | amendment. It is a figure which shows the other structural example of the equalizing process part of this embodiment.

Explanation of symbols

11-CPU, 12-equalizing processing unit, 13-D / A converter, 14-power amplifier, 15-speaker, 16-microphone, 17-echo processing unit, 18-A / D converter, 19-mixer, 20-sound source 21-test sound source, 22-characteristic measuring unit

Claims (5)

An acoustic characteristic correction system that corrects an acoustic characteristic of a system in which sound emitted from the speaker is propagated to the microphone position in a predetermined space where a microphone and a speaker are installed, to a desired acoustic characteristic,
Equalizing means for performing the correction by dividing the sound pickup signal of the microphone into a plurality of frequency band components and giving adjustment of a predetermined frequency characteristic to each frequency band component;
Correction characteristic calculating means for calculating a correction characteristic for causing the equalizing means to execute the correction, and
The correction characteristic calculation means individually sets an enhancement direction correction frequency range for performing correction for increasing the signal level and a suppression direction correction frequency range for performing correction for decreasing the signal level.
Acoustic characteristic correction system.   The acoustic characteristic correction system according to claim 1, wherein the correction characteristic calculation unit sets a high-frequency threshold frequency of the enhancement direction correction frequency range to be lower than a high-frequency threshold frequency of the suppression direction correction frequency range.   The acoustic characteristic correction system according to claim 2, wherein the correction characteristic calculation unit sets a high-frequency threshold frequency of the enhancement direction correction frequency range based on a high-frequency attenuation characteristic of the sound emission characteristic of the speaker.   The said correction characteristic calculating means sets the low frequency side threshold frequency of the said enhancement direction correction frequency range higher than the low frequency side threshold frequency of the said suppression direction correction frequency range. Acoustic characteristic correction system.   5. The sound according to claim 4, wherein the correction characteristic calculation means sets a low-frequency threshold frequency of the enhancement direction correction frequency range based on a sound emission characteristic of the speaker and a low-frequency attenuation characteristic of a sound collection characteristic of the microphone. Characteristic correction system.

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