JP2010250243A - Impulse response measuring system in multi-channel sound, reverberation creating device and reverberation creating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impulse response measuring system in multi-channel sound, a reverberation creating device and a reverberation creating system, by which requirement for creating a content is fully satisfied, and reverberation can be added based on variety of characteristics of an existing reverberation sound field including a low frequency region. <P>SOLUTION: The impulse response measurement system for measuring impulse response in the reverberation sound field includes: a measurement signal creation section 201, measurement signal dividing sections 202 and 203; a high frequency signal sound output section 101 and a low frequency signal sound output section 102; a plurality of first sound collecting units 206 for creating a high region impulse response 208 by collecting output sound of the high frequency signal sound output section 101; and a plurality of second sound collecting units 207 for creating a low region impulse response 209 by collecting output sound of the low frequency signal sound output section 102. Sound collection by the first sound collecting units 206 and sound collection by the second sound collecting units 207 are separately performed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention measures an impulse response (room acoustic characteristics) and generates reverberation (early reflection and rear reverberation) based on the characteristics, an impulse response measurement system in multi-channel sound, a reverberation sound generation device, and reverberation sound generation It is about the system.

  In multi-channel sound content production, a device that artificially adds reverberation to a sound source without reverberation is essential. Conventionally, reverberation is achieved using room acoustic characteristics (impulse response) measured in an actual reverberation space. A generating device is known (see, for example, FIG. 4 of Non-Patent Document 1). Impulse response measurement is a technique used to simulate what kind of direct sound and indirect sound (reverberation sound) can be heard at architectural reference points in architectural sound. On the other hand, in content production that requires adding indirect sounds (reverberation sounds) such as early reflections and rear reverberation sounds to a certain sound source, only the characteristics of indirect sounds excluding direct sounds can be simulated as high as possible. Is required.

  FIG. 10 shows the arrangement of microphones in a conventional directional impulse response measurement system in a reverberant sound field such as a concert hall used in architectural sound.

  In the direction-specific impulse response, a plurality of measurement sounds reproduced from the omnidirectional speaker 1001 placed in the sound source area are arranged at equal intervals on the circumference around the measurement reference point 1007 in the viewing area (as an example in FIG. 10). It is measured by picking up sound with unidirectional microphones 1002 to 1009 arranged eight). In the case of a concert hall, the sound source area is the stage and the viewing area is the audience seat. The arrows of the unidirectional microphones 1002 to 1009 in the figure indicate the directivity direction.

  In architectural acoustics, the response may be measured with a single omnidirectional microphone placed at the measurement point. However, in order to use multi-channel acoustics, the response from multiple directions to the measurement reference point is generally used. Is often measured. In the conventional multi-channel sound system such as 5.1-channel sound, the speaker is arranged in a single plane. Therefore, this measurement is also performed with a unidirectional microphone on the circumference in the single plane. The measuring method to arrange is generally used.

  A conventional reverberant sound generation system will be described with reference to FIGS. 11 and 12. The reverberant sound generation system includes an impulse response measurement system that measures an impulse response in a reverberant sound field, and a reverberation sound generator that generates reverberation using the impulse response. FIG. 11 is a configuration diagram of a conventional direction-specific impulse response measurement system, and FIG. 12 is a configuration diagram of a conventional reverberation sound generation device.

  The conventional impulse response measurement system includes a measurement signal generation device 1100 and a unidirectional microphone group 1103. The measurement signal generation device 1100 includes a measurement signal generation unit 1101, an amplification amplifier 1102, and an omnidirectional speaker 1001.

  The measurement signal generator 1101 generates a measurement signal represented by a time stretched pulse (TSP) signal. The measurement signal is amplified by the amplification amplifier 1102 and output from the omnidirectional speaker 1001. Unidirectional microphone group 1103 is unidirectional microphones 1002 to 1009 arranged as shown in FIG. Then, each unidirectional microphone picks up the measurement sound output from the omnidirectional speaker 1001, whereby the impulse response 1104 is obtained.

  The conventional reverberation sound generation device includes an input signal generation unit 1201 and a convolution operation unit 1202.

  The input signal generation unit 1201 generates an input signal (a signal to which reverberation sound is desired to be added). The convolution operation unit 1202 performs a convolution operation on the input signal generated by the input signal generation unit 1201 and the impulse response 1104 and outputs a reverberation sound 1203.

  Thus, in the conventional reverberant sound generation system, the impulse response in the reverberant sound field is obtained by the direction-specific impulse response measurement system shown in FIG. 11, and the impulse response is input to the reverberant sound generator shown in FIG. A reverberant sound was generated.

The Journal of the Institute of Image Information and Television Engineers Vol.61, No.5 (2007) pp.638-644

  The reverberation time means the time from the stop of the presentation after the measurement sound pressure is in a steady state by the direct sound presentation until the measurement sound pressure decreases by about 60 dB. It is required to measure the pressure change correctly. Therefore, in the impulse response measurement, it is essential to measure the response while ensuring as high an S / N ratio as possible. However, in general concert halls and the like, there is often background noise due to air conditioning or outsiders, and due to the inherent noise of the measurement microphone, a sufficient S / N ratio cannot often be secured in the measurement system. In such a case, it is necessary to set the gain of the microphone preamplifier so that the sound pressure level of the measurement signal generated from the speaker is increased as much as possible and the SN ratio is increased accordingly.

  However, the upper limit of the gain setting of the microphone preamplifier is determined by the sound reception level of the unidirectional microphone 1002 facing the omnidirectional speaker. This is because the unidirectional microphone that receives the largest direct sound component from the omnidirectional speaker 1001 is the unidirectional microphone 1002 that faces the omnidirectional speaker, and from the omnidirectional speaker 1001. This is because the direct sound component arriving at the unidirectional microphone 1002 has the highest sound pressure level as compared with the indirect sound component arriving thereafter.

  As described above, in the conventional measurement system, the upper limit of the dynamic range of the measurement system is determined by the direct sound arrival level, and there is a problem that characteristics that can withstand the intended application of reverberation cannot be obtained.

  In addition, as the omnidirectional speaker 1001 for generating a measurement signal used in the conventional measurement system, a speaker in which a plurality of speaker units are arranged on a spherical surface, such as a dodecahedron speaker, is used. I had to get smaller. For this reason, there is a limit to low frequency reproduction, and there is a problem that the low frequency (bass) reverberation characteristics that are particularly important in content production cannot be reproduced sufficiently.

  An object of the present invention is to solve the above-mentioned problems in multi-channel sound that sufficiently satisfies the requirements in content production and enables reverberation addition based on characteristics of various existing reverberation sound fields including low frequencies. An impulse response measurement system, a reverberation sound generation device, and a reverberation sound generation system are provided.

  In order to solve the above problems, an impulse response measurement system for multi-channel sound according to the present invention is an impulse response measurement system for measuring an impulse response in a reverberant sound field, the measurement signal generating means for generating a measurement signal, Measurement signal dividing means for dividing the measurement signal generated by the measurement signal generating means into a high frequency measurement signal and a low frequency measurement signal, and a high frequency sound output means for outputting the high frequency measurement signal generated by the measurement signal dividing means as sound A low-frequency sound output means for outputting a low-frequency measurement signal generated by the measurement signal dividing means; a sound output by the high-frequency sound output means is collected by a plurality of first sound collectors; The high frequency impulse response generating means for generating the impulse response and the sound output by the low frequency sound output means are collected by a plurality of second sound collectors, And a low-pass impulse response generation means for generating a scan response, sound pickup by the first sound pickup and the second collecting device by the sound collecting device is characterized by being carried out separately.

  Further, in the impulse response measurement system for multi-channel sound according to the present invention, the number of the first sound collectors and the number of the second sound collectors are the high frequency impulses generated by the high frequency impulse response generating means. It is the same as the number of channels of multi-channel sound that reproduces a signal to which a reverberation sound obtained from the response and the low-frequency impulse response generated by the low-frequency impulse response generation means is added.

  In the impulse response measurement system for multi-channel sound according to the present invention, when measuring an impulse response of an LFE (Low Frequency Effects) channel, the number of the first sound collectors is the high-frequency impulse response generation means. The number of channels is the same as the number of channels except for the LFE channel of multi-channel sound that reproduces a signal added with a reverberation sound obtained from the high-frequency impulse response generated by the low-frequency impulse response generated by the low-frequency impulse response generation means, The number of second sound collectors is the same as the number of LFE channels of the multichannel sound.

  In the impulse response measurement system for multi-channel sound according to the present invention, when measuring the impulse response of the LFE channel, the number of the first sound collectors is the high frequency generated by the high frequency impulse response generating means. The number of channels is the same as the number of channels except for the LFE channel of multi-channel sound for reproducing the impulse response and the reverberant signal obtained from the low-frequency impulse response generated by the low-frequency impulse response generating means. The impulse response measurement system according to claim 1, wherein the number of devices is the same as the number of channels of the multi-channel sound.

  Further, in the impulse response measurement system for multi-channel sound according to the present invention, the first sound collector is a bidirectional microphone, and is arranged so that a null direction is directed toward a sound source area, and the second sound collector Is an omnidirectional microphone.

  Furthermore, the reverberation sound generating device for multi-channel sound according to the present invention is a reverberation sound generating device for generating reverberation sound in multi-channel sound, the input signal generating means for generating an input signal, and the input signal as a high frequency band. Input signal dividing means for dividing the input signal into a low-frequency input signal, and a high-frequency impulse response generated by the high-frequency impulse response generating means in the impulse response measurement system according to any one of claims 1 to 5, A first convolution operation means for performing a convolution operation with the high frequency input signal to generate a high frequency reverberation sound, a low frequency impulse response generated by a low frequency impulse response generation means of the impulse response measurement system, and And a second convolution operation means for performing a convolution operation with the low-frequency input signal and generating a low-frequency reverberation sound. .

  In the reverberation sound generating device for multi-channel sound according to the present invention, the reverberation sound generating device further includes adding means for adding the high frequency reverberation sound and the low frequency reverberation sound.

  Further, in the reverberant sound generating device for multi-channel sound according to the present invention, the reverberant sound generating device further includes comparison means for comparing the number n of the high-frequency reverberant sound and the number m of the low-frequency reverberant sound, When the comparison means determines that m> n, n high-frequency reverberation sounds and n low-frequency reverberation sounds are added by the addition means, and (mn) low-frequency reverberation sounds. Is output as it is.

  Furthermore, the reverberation sound generation system in the multi-channel sound according to the present invention includes the impulse response measurement system according to any one of claims 1 to 5 and the reverberation sound according to any one of claims 6 to 8. And a generating device.

  According to the present invention, it is possible to generate a high-quality and wide-band reverberation sound. As a result, it is possible to add various reverberations that could not be realized in the past, and to increase the creativity of content sound production for a multi-channel sound system.

It is a figure which shows arrangement | positioning of the microphone in the impulse response measuring system of Example 1 by this invention. It is a block diagram of the impulse response measurement system of Example 1 by this invention. It is a block diagram of the reverberation sound production | generation apparatus of Example 1 by this invention. It is a figure which shows arrangement | positioning of the microphone in the impulse response measuring system of Example 2 by this invention. It is a block diagram of the reverberation sound production | generation apparatus of Example 2 by this invention. It is a figure which shows arrangement | positioning of the microphone in the impulse response measuring system of Example 3 by this invention. It is a block diagram of the reverberation sound production | generation apparatus of Example 3 by this invention. It is a figure which shows the directional characteristic and frequency characteristic of a bidirectional microphone. It is a figure which shows the directional characteristic and frequency characteristic of an omnidirectional microphone. It is a figure which shows arrangement | positioning of the microphone in the conventional measurement system of the impulse response according to direction. It is a block diagram of the conventional impulse response measuring system according to direction. It is a block diagram of the conventional reverberation sound production | generation apparatus.

  Embodiments of the present invention will be described below with reference to the drawings.

  A reverberation sound generation system according to a first embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3. The reverberation sound generation system includes an impulse response measurement system that measures an impulse response in a reverberation sound field, and a reverberation sound generation device that generates a reverberation sound using the impulse response. FIG. 1 is a diagram showing the arrangement of microphones in an impulse response measurement system. FIG. 2 is a configuration diagram of the impulse response measurement system. FIG. 3 is a configuration diagram of the reverberation sound generation device.

[Mic placement in impulse response measurement system]
As a speaker that generates measurement sound, in addition to the omnidirectional speaker 101, a low-frequency dedicated speaker 102 that can reproduce a heavy bass range that cannot be reproduced by the omnidirectional speaker 101 is used in combination. Note that these two speakers do not generate measurement sound at the same time, but individually generate measurement sound and perform measurement individually as described later.

  The microphones that collect the measurement sound are arranged in a distributed manner at necessary measurement points as described later, with the omnidirectional microphones 103 to 111 and the omnidirectional microphones 112 to 120 as a pair. The arrows of the bidirectional microphones 103 to 111 in the figure indicate the directivity direction. In the present embodiment, a case where the number of omnidirectional microphones and omnidirectional microphones is nine will be described.

  The microphone is not arranged on the circumference around one measurement reference point 1007 as in the conventional example shown in FIG. 10, but in a place where it is easy to collect reflected sound from the indoor side wall or ceiling. Distributed. Specifically, the omnidirectional microphones 103 to 111 are arranged apart from a range where the ratio of the direct sound and the indirect sound output from the speaker is 1: 1, and the interval between the adjacent directional microphones is mutually separated. It arrange | positions so that it may become equal distance. Further, the distance from the side surface is desirably 1/2 or more of the wavelength of the lowest frequency of the response measured by the bidirectional microphone. For example, when the lowest frequency is 100 Hz, the desirable distance from the side surface is 1.7 m or more. Note that the microphone is not only on a single plane, but in a multi-channel acoustic system in which speakers represented by, for example, 22.2 multi-channel acoustic system are three-dimensionally arranged, the microphone is also three-dimensionally changed in height. , Distributed at necessary measurement points. FIG. 1 shows, as an example, a case where measurement is performed with nine planar points for easy understanding, but there are 22 measurement points corresponding to 22.2 multi-channel sound.

  The bi-directional microphone generally has a directivity characteristic shown in FIG. Therefore, it arrange | positions so that the null direction (direction with the lowest sensitivity) may face the speaker side. In general, since the speaker is often placed in the center of the sound source area, as shown in FIG. 1, the bidirectional microphones 103 to 111 are arranged so that the positive directivity direction is the side wall and the null direction is toward the sound source area. Is done.

  By arranging the omnidirectional microphones 103 to 111 in such a direction, the sound pressure level of the direct sound component arriving at the omnidirectional microphones 103 to 111 from the omnidirectional speaker 101 is greatly reduced compared to the conventional example. Therefore, the gain of the preamplifier (not shown) of the bidirectional microphones 103 to 111 can be increased by that amount. As a result, it is possible to measure even smaller reverberation components than in the conventional example, and the quality of the measured reverberation characteristics can be improved.

  In addition, the bidirectional microphone generally has the frequency characteristics shown in FIG. 8B, and the relative sensitivity decreases from around 200 Hz, and decreases by about 3 dB around 100 Hz.

  On the other hand, the omnidirectional microphone generally has a directivity characteristic shown in FIG. 9A and a frequency characteristic shown in FIG. 9B. Unlike the omnidirectional microphone, the omnidirectional microphone has a substantially flat frequency characteristic from 20 Hz to 20 kHz, and there is almost no decrease in relative sensitivity.

  Therefore, in the impulse response measurement system according to the present invention, the measurement signal is divided into a high frequency region and a low frequency region at a low frequency cut frequency Fc (for example, Fc = 200 Hz). Measurement is performed using the omnidirectional microphones 103 to 111, and the low frequency is measured independently using the low frequency dedicated speaker 102 and the omnidirectional microphones 112 to 120. As shown in FIG. 1, the omnidirectional microphones 112 to 120 for measuring the low-frequency impulse response are distributed at the same measurement point as the omnidirectional microphones 103 to 111. For example, the omnidirectional microphone 103 and the omnidirectional microphone 112 are arranged at the same position.

  By doing so, it becomes possible to measure a low-frequency reverberation response that could not be sufficiently measured in the conventional example, and can sufficiently cope with the reverberation sound quality required in content production.

  In addition, the arrangement position of the microphone is not limited to the position shown in FIG. 1, and can be arbitrarily arranged at a measurement point where a reverberation sound is desired to be added.

  Next, the configuration and operation of the impulse response measurement system according to the present invention will be described with reference to FIG.

[Configuration and operation of impulse response measurement system]
The impulse response measurement system includes a measurement sound generator 200, a bidirectional microphone group 206, and an omnidirectional microphone group 207. The measurement sound generator 200 includes a measurement signal generator 201, a changeover switch 210, a high-pass filter 202, a low-pass filter 203, amplification amplifiers 204 and 205, an omnidirectional speaker 101, and a low-frequency dedicated device. And a speaker 102.

  The measurement signal generation unit 201 has a function of generating a measurement signal typified by a time stretched pulse (TSP) signal.

  The changeover switch 210 has a function of inputting a measurement signal to the high-pass filter 202 when measuring a high-frequency impulse response, and inputting the measurement signal to the low-pass filter 203 when measuring a low-frequency impulse response. .

  The high-pass filter 202 has a function of passing only a high-frequency signal having a high frequency (f ≧ Fc) equal to or higher than the low-frequency cut frequency Fc in the measurement signal, and the low-pass filter 203 is a low-pass filter among the measurement signals. It has a function of passing only a low frequency signal having a frequency lower than the frequency cut frequency Fc (f <Fc). Fc is set to a frequency (for example, Fc = 200 Hz) at which the relative sensitivity of the omnidirectional microphones 103 to 111 decreases.

  The amplification amplifier 204 amplifies the high-frequency measurement signal after passing through the high-pass filter 202, and the amplification amplifier 205 has a function of amplifying the low-frequency measurement signal after passing through the low-pass filter 203. If the measurement signal is sufficiently large, the amplification amplifiers 204 and 205 are not necessary.

  The omnidirectional microphone group 206 is the omnidirectional microphones 103 to 111 arranged as shown in FIG. 1, and collects high-frequency sound generated from the omnidirectional speaker 101 at each measurement point. The omnidirectional microphone group 207 is omnidirectional microphones 112 to 120 arranged as shown in FIG. 1, and collects a low frequency sound generated from the low frequency dedicated speaker 102 at each measurement point.

  The high-frequency impulse response 208 is an impulse response measured by the omnidirectional microphone group 206, and the low-frequency impulse response 209 is an impulse response measured by the omnidirectional microphone group 207. Since there are nine high-frequency signal measurement points (the number of bidirectional microphones is nine), nine high-frequency impulse responses 208 are obtained, and nine low-frequency signal measurement points (of the omnidirectional microphone). 9), nine low-frequency impulse responses 209 are obtained.

  According to the present impulse response measurement system, when measuring a high-frequency impulse response, the measurement signal generated by the measurement signal generation unit 201 is extracted only by the high-pass filter 202, and is amplified by the amplification amplifier 204. After being amplified, sound is output from the omnidirectional speaker 101. Then, the high-frequency impulse response 208 is obtained by the bidirectional microphone group 206. On the other hand, when measuring the low-frequency impulse response, the measurement signal generated by the measurement signal generation unit 201 is extracted only by the low-pass filter 203 and amplified by the amplification amplifier 205, Sound is output from the dedicated speaker 102. Then, the low-frequency impulse response 209 is obtained by the omnidirectional microphone group 207. The high-frequency impulse response 208 and the low-frequency impulse response 209 are input to a reverberation sound generation device described below.

  Next, the configuration and operation of the reverberant sound generating device according to the present invention will be described with reference to FIG.

[Configuration and operation of reverberation generator]
The reverberation sound generation device includes an input signal generation unit 301, a high-pass filter 302, a low-pass filter 303, convolution operation units 304 and 305, level adjusters 306 and 307, and an adder 308.

  The input signal generation unit 301 has a function of generating a signal to which a reverberation sound is desired to be added.

  The high-pass filter 302 has a function of passing only a high-frequency signal having a high frequency (f ≧ Fc) equal to or higher than the low-frequency cut frequency Fc in the measurement signal, and the low-pass filter 303 is a low-pass filter among the measurement signals. It has a function of passing only a low frequency signal having a frequency lower than the frequency cut frequency Fc (f <Fc). Fc is the same as the frequency set by the high-pass filter 202 and the low-pass filter 203 of the impulse response measurement system.

  The convolution operation unit 304 performs a convolution operation of the measurement signal that has passed through the high-pass filter 302 and the high-frequency impulse response 208, and the convolution operation unit 305 performs the measurement signal that has passed through the low-pass filter 303 and the low-frequency impulse. The convolution operation of the response 209 is performed. Since the high-frequency impulse response 208 and the low-frequency impulse response 209 are respectively obtained by the number of measurement points (9), the convolution calculation is also performed 9 times.

  The level adjusters 306 and 307 have a function of adjusting the levels of the high-frequency reverberation sound and the low-frequency reverberation sound obtained by the convolution calculators 304 and 305, respectively, in order to generate an optimal reverberation sound. In addition, although it is preferable to have the level adjusters 306 and 307, the effect of the present invention can be obtained without it.

  The adder 308 has a function of adding a high frequency reverberation sound and a low frequency reverberation sound to generate a reverberation sound 309. The reverberation sound 309 is a reverberation sound at each measurement point, and is generated by the number of measurement points (9).

  According to the reverberant sound generation device, the input signal generated by the input signal generation unit 301 is divided into a high-frequency input signal and a low-frequency input signal by the high-pass filter 302 and the low-pass filter 303. A high frequency reverberation sound is obtained by performing a convolution operation between the high frequency input signal and the high frequency pulse response 208 by the convolution calculation unit 304, and the high frequency input signal and the high frequency pulse response 208 are convolved by the convolution calculation unit 305. High-frequency reverberation can be obtained by calculation. Thereafter, the level adjusters 306 and 307 adjust the levels of the high-frequency reverberation sound and the low-frequency reverberation sound, respectively, and the adder 308 adds the adjusted high-frequency reverberation sound and low-frequency reverberation sound. Is generated.

  A reverberation effect is obtained by adding the reverberant sound obtained by this apparatus to the original input signal. In content production with multi-channel sound, for a sound source (input signal) to which reverberation is to be added, n reverberation sounds are generated by a reverberation sound generation device, and each reverberation sound corresponds to a measurement point and a speaker (channel) The desired reverberation effect can be obtained.

  Next, a reverberant sound generation system when using a low-frequency effect channel called LFE used in a multi-channel sound reproduction system will be described as a second embodiment. For example, the 5.1 channel system has one LFE channel, and the 22.2 channel system has two LFE channels. About the same part as Example 1, the same referential mark is attached | subjected and description is abbreviate | omitted.

  FIG. 4 shows the arrangement of microphones in the impulse response measurement system according to the second embodiment. In the impulse response measurement system according to the first embodiment, the omnidirectional microphones and the omnidirectional microphones are distributed in pairs, but in the second embodiment, the same number of omnidirectional microphones as the number of LFE channels are arranged sufficiently apart. To do. It is desirable that the distance between the omnidirectional microphones is ½ or more of the wavelength of the lowest frequency of the low-frequency impulse response to be measured. For example, when the lowest frequency is 40 Hz, a desirable distance between omnidirectional microphones is 4.25 m or more. FIG. 4 shows the case where there are two LFE channels, and the omnidirectional microphones 401 and 402 and the omnidirectional microphones 106 to 108 are arranged at equal intervals. When the LFE channel is one channel, one omnidirectional microphone is arranged in the center of the viewing area. The arrangement positions and the arrangement directions of the bidirectional microphones 103 to 111 are the same as those in the first embodiment.

  The configuration of the impulse response measurement system is the same as that of the impulse response measurement system according to the first embodiment shown in FIG. The omnidirectional microphone group 206 is the omnidirectional microphones 103 to 111 arranged as shown in FIG. 4, and the omnidirectional microphone group 207 includes the omnidirectional microphone 401 and the omnidirectional microphone 401 arranged as shown in FIG. 402. Since there are nine high-frequency signal measurement points (the number of bi-directional microphones is nine), nine high-frequency impulse responses 208 are obtained, and two low-frequency signal measurement points (two omnidirectional microphones). Therefore, two low-frequency impulse responses 209 are obtained.

  FIG. 5 illustrates a configuration of a reverberation sound generation device according to the second embodiment. The convolution operation unit 304 performs nine convolution operations since nine high-frequency impulse responses 208 are obtained, and generates nine high-frequency reverberation sounds 501. Since the two low-frequency impulse responses 209 are obtained, the convolution operation unit 305 performs the convolution operation twice to generate two low-frequency reverberation sounds 502.

  In content production, in addition to the source sound, n high-frequency reverberation sounds generated from the original sound (input signal) are reproduced from the speakers corresponding to each channel, and m low-frequency reverberation sounds are transmitted to each LFE channel. Play from the corresponding low-frequency speaker.

  The reverberation sound generation system (impulse response measurement system and reverberation sound generation apparatus) of the second embodiment can sufficiently satisfy the quality of reverberation sound required for content production. The system can be simplified as compared with the first embodiment, and the cost merit can be increased accordingly.

  Next, a modification of the second embodiment will be described as a third embodiment when the number of LFE channels is two. About the same part as Example 1 or Example 2, the same referential mark is attached | subjected and description is abbreviate | omitted.

  FIG. 6 shows the arrangement of microphones in the impulse response measurement system according to the third embodiment. The arrangement positions and arrangement directions of the bidirectional microphones 103 to 111 are the same as those in the first and second embodiments. The arrangement positions of the omnidirectional microphones 601 to 609 are the same as those of the omnidirectional microphones 112 to 120 of the first embodiment. The arrangement positions of the omnidirectional microphones 610 and 611 are the same as those of the omnidirectional microphones 401 and 402 of the second embodiment.

  The configuration of the impulse response measurement system is the same as that of the impulse response measurement system according to the first embodiment shown in FIG. The omnidirectional microphone group 206 is the omnidirectional microphones 103 to 111 arranged as shown in FIG. 6, and the omnidirectional microphone group 207 is the omnidirectional microphones 601 to 601 arranged as shown in FIG. 611. Since there are nine high-frequency signal measurement points (the number of bi-directional microphones is nine), nine high-frequency impulse responses 208 are obtained, and eleven low-frequency signal measurement points (of omnidirectional microphones). Therefore, 11 low-frequency impulse responses 209 are obtained.

  FIG. 7 shows the configuration of an impulse response measurement system according to the third embodiment. The convolution operation unit 304 performs nine convolution operations since nine high-frequency impulse responses 208 are obtained, and generates nine high-frequency reverberation sounds 501. Since the eleven low-frequency impulse responses 209 are obtained, the convolution operation unit 305 performs the convolution operation 11 times, and corresponds to nine points among the calculation results in which the omnidirectional microphones and the omnidirectional microphones are distributed in pairs. Nine calculation results are output to the level adjuster 307. The adder 308 adds the high frequency reverberation sound and the low frequency reverberation sound, and generates nine reverberation sounds 701. The convolution operation unit 305 outputs two operation results corresponding to the omnidirectional microphones 610 and 611 among the operation results as the low-frequency reverberation sound 702.

  According to the reverberation sound generation system (impulse response measurement system and reverberation sound generation device) of the third embodiment, the quality of the reverberation sound can be further improved.

  Each of the above-described embodiments has been described as a representative example. However, many modifications and replacements can be made within the spirit and scope of the present invention, and each embodiment can be combined to realize another embodiment. It will be apparent to those skilled in the art that Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims.

  As described above, according to the present invention, a high-quality reverberation sound can be generated, which is useful for any application for adding a reverberation sound.

DESCRIPTION OF SYMBOLS 101 Omnidirectional speaker 102 Low frequency exclusive speaker 201 Measurement signal generation part 202 High pass filter 203 Low pass filter 204, 205 Amplification amplifier 206 Bidirectional microphone 207 Omnidirectional microphone 208 High frequency impulse response 209 Low frequency impulse response 301 Input signal generator 302 High-pass filter 303 Low-pass filter 304, 305 Convolution operation unit 306, 307 Adder 308 Adder 309 Reverberation sound

Claims (9)

An impulse response measurement system for measuring an impulse response in a reverberant sound field,
Measurement signal generating means for generating a measurement signal;
Measurement signal dividing means for dividing the measurement signal generated by the measurement signal generating means into a high frequency measurement signal and a low frequency measurement signal;
High frequency sound output means for outputting a high frequency measurement signal generated by the measurement signal dividing means;
Low-frequency sound output means for outputting a low-frequency measurement signal generated by the measurement signal dividing means;
High-frequency impulse response generating means for collecting the sound output by the high-frequency sound output means with a plurality of first sound collectors and generating a high-frequency impulse response;
Low-frequency impulse response generating means for collecting the sound output by the low-frequency sound output means with a plurality of second sound collectors and generating a low-frequency impulse response;
The impulse response measurement system, wherein sound collection by the first sound collector and sound collection by the second sound collector are performed separately.   The number of the first sound collectors and the number of the second sound collectors are a high-frequency impulse response generated by the high-frequency impulse response generating unit and a low-frequency impulse response generated by the low-frequency impulse response generating unit. 2. The impulse response measurement system according to claim 1, wherein the number of channels is the same as the number of channels of multi-channel sound that reproduces a signal to which a reverberation sound obtained from the above is added. When measuring the impulse response of the LFE channel, the number of the first sound collectors includes a high-frequency impulse response generated by the high-frequency impulse response generation unit and a low-frequency impulse generated by the low-frequency impulse response generation unit. It is the same as the number of channels excluding the LFE channel of multi-channel sound that reproduces the signal with the reverberation sound obtained from the response,
The impulse response measurement system according to claim 1, wherein the number of the second sound collectors is the same as the number of LFE channels of the multi-channel sound. When measuring the impulse response of the LFE channel, the number of the first sound collectors includes a high-frequency impulse response generated by the high-frequency impulse response generation unit and a low-frequency impulse generated by the low-frequency impulse response generation unit. It is the same as the number of channels excluding the LFE channel of multi-channel sound that reproduces the signal with the reverberation sound obtained from the response,
The impulse response measurement system according to claim 1, wherein the number of the second sound collectors is the same as the number of channels of the multi-channel sound.   The first sound collector is a bi-directional microphone and is arranged so that a null direction is directed toward a sound source area, and the second sound collector is an omnidirectional microphone. The impulse response measurement system according to any one of claims 1 to 4. A reverberation sound generating device for generating reverberation sound in multi-channel sound,
Input signal generating means for generating an input signal;
Input signal dividing means for dividing the input signal into a high-frequency input signal and a low-frequency input signal;
A high frequency reverberation sound is obtained by performing a convolution operation between the high frequency impulse response generated by the high frequency impulse response generating means in the impulse response measurement system according to any one of claims 1 to 5 and the high frequency input signal. First convolution operation means for generating
A low-frequency impulse response generated by the low-frequency impulse response generating means of the impulse response measurement system; and a second convolution calculation means for generating a low-frequency reverberation sound by performing a convolution calculation with the low-frequency input signal. A reverberant sound generator characterized by the above.   The reverberation sound generation device according to claim 6, further comprising addition means for adding the high frequency reverberation sound and the low frequency reverberation sound. The reverberant sound generating apparatus further includes a comparison unit that compares the number n of the high-frequency reverberant sounds with the number m of the low-frequency reverberant sounds,
When the comparison means determines that m> n, n high-frequency reverberation sounds and n low-frequency reverberation sounds are added by the addition means, and (mn) low-frequency reverberation sounds. The reverberant sound generating apparatus according to claim 7, wherein the reverberant sound is output as it is. The impulse response measurement system according to any one of claims 1 to 5,
A reverberant sound generating system comprising: the reverberant sound generating device according to any one of claims 6 to 8.

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