JP2007124023A - Method of reproducing sound field, and method and device for processing sound signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust the feeling of reverberation, and that of sound localization when reproducing a sound field in a measurement environment in environment differing from the measurement one, based on a transfer function corresponding to each of a plurality of positions on a closed surface measured in the measurement environment. <P>SOLUTION: In a reproduction environment 11, a sound signal S is outputted from a dry sound output speaker 9 arranged in a position corresponding to a sound image position without performing arithmetic processing based on the transfer function. Voice as dry sound outputted from the dry sound output speaker 9 is mixed with a reproduction signal SH output from each speaker 8 for reproduction spatially, thus restraining the feeling of reverberation by reproduced voice, and increasing the feeling of sound localization. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sound field reproduction method for reproducing a sound field of one environment in another environment. The present invention also relates to an audio signal processing method and an audio signal processing apparatus suitable for reproducing a sound field of one environment in another environment.

JP 2002-186100 A

For example, when viewing and listening to content such as movies and music, reverberation is added to give the reproduced sound a sense of reality.
As the reverberation adding process, a so-called digital reverb method is known. This digital reverb method generates a lot of delay information that is random delay time with respect to the original sound, and further reduces the volume as the delay time becomes longer, or applies feedback at places where the delay time is longer to reduce the reverberation time Signal processing such as taking a long time is performed. As a result, a reverberation effect can be artificially generated for the original sound.
However, since the parameters for generating the delay information are set based on the audibility of the operator who sets the parameters, this setting work is complicated. In addition, there is no concept of localizing the original sound because it artificially creates reverberation, and it is not excellent in reproducing the sound field.

On the other hand, as a technique for actually measuring an impulse response in a sound field space and obtaining a reverberation effect based on spatial information such as localization of a sound source, for example, the technique described in Patent Document 1 is known. Yes.
In the technique described in Patent Document 1, for example, as shown in FIG. 1, a measurement speaker 3 is arranged as a sound source in a measurement environment (measurement sound field) 1 such as a hall. Then, a sound signal for impulse response measurement, such as a TSP (Time Streched Pulse) signal, is supplied to the measurement speaker 3 and a plurality of measurement microphones 4 (a) arranged at required positions in the same sound field. To p), the measurement sound output from the measurement speaker 3 is input. In this case, for example, in the measurement microphone 4a, as indicated by an arrow in FIG. 1, the direct sound from the measurement speaker 3 and the reflected sound output from the measurement speaker 3 and reflected in the hall as the measurement environment Can be detected. Although not shown, this is the same for the other measurement microphones 4b, 4c, 4d,.
Therefore, a transfer function corresponding to each of the measurement microphones 3 to 4 is measured by measuring an impulse response including reverberation based on the audio signal detected by each measurement microphone 4 (ap). Can be requested.

If such a transfer function is used, for example, as shown in FIG. 3, an environment (reproduction environment 11) in which speakers 8 (ap) are arranged in the same positional relationship as each measurement microphone 4 in the case of FIG. Thus, the sound field in the measurement environment 1 of FIG. 1 can be reproduced.
That is, when the transfer functions corresponding to the respective arrangement positions of the respective measurement microphones 4 are obtained as described above, the arrangement of the speakers 8 is obtained by convolving the audio signals to be reproduced using these transfer functions. An audio signal to be output from the position is obtained. Therefore, by outputting these audio signals from the speakers 8 arranged at corresponding positions, the reverberation effect similar to that of the measurement environment 1 in FIG. 1 can be obtained in the space surrounded by the speakers 8.
Since such a method uses a transfer function actually measured, it has excellent sound field reproducibility during reproduction. At the same time, the sound localization is clear.

  At this time, what is important is that the measurement microphone 4 (ap) in the measurement environment 1 of FIG. 1 and the speaker 8 (ap) in the reproduction environment 11 of FIG. Is to be placed. By doing in this way, the localization of the sound source of the measurement sound field (sound image localization) can be clearly reproduced in the region (closed curved surface) surrounded by the speaker 8 in the reproduction environment 11. It is possible to clearly reproduce the sound field.

  In this way, according to the method described in Patent Document 1, by performing sound reproduction based on the actual sound measurement result in a measurement environment such as a hall, the measurement environment can be set in a space different from the measurement environment. A unique reverberation feeling and a virtual sound image localization feeling can be provided.

  However, in such a sound field reproduction method, for example, the number of microphones 4 used in the measurement environment, that is, the number of speakers 8 used in the reproduction environment is extremely small, or the distance between the microphones 4, that is, the distance between the speakers 8 is extremely large. In some cases, it may not be possible to obtain a feeling of reverberation / localization when it is too wide. Specifically, a sound with blurred reverberation and a blurred outline as heard in a large hall will be reproduced.

Therefore, in the present invention, in view of the above problems, the sound field reproduction method is as follows.
That is, first, a sound generation step of sound generation from a required sound generation position outside the closed curved surface is provided.
Also, transfer function generation for generating a transfer function for the sound reaching each of the plurality of positions from the sound generation position based on the result of measuring the sound generated in the sound generation step for each of the plurality of positions on the closed curved surface A process is provided.
A reproduction audio signal generating step of performing an arithmetic process based on the transfer function generated in the transfer function generation step on the input audio signal to obtain a reproduction audio signal corresponding to each of the plurality of positions; .
Also, reproduction audio outputs for outputting the reproduction audio signals generated in the reproduction audio signal generation step from a plurality of first speakers arranged so as to have a geometrically equivalent positional relationship with the plurality of positions. A process is provided.
In addition, the audio signal is output without performing the arithmetic processing from the second speaker arranged for the plurality of first speakers so as to have the same positional relationship as the sound generation position with respect to the closed curved surface. A dry audio output process is provided.

As described above, the audio signal is subjected to the arithmetic processing from the second speaker arranged for the plurality of first speakers so as to have the same positional relationship as the sound generation position with respect to the closed curved surface. Is output to the listener in the space surrounded by the first speaker, along with the reproduced sound from the first speaker and the sound (dry sound) based on the reproduced sound corresponding to the sounding position. It is output from the position (virtual sound image position).
By outputting the reproduced sound and the dry sound from the virtual sound image position in this way, the sense of localization of the sound image can be increased and the reverberation feeling can be suppressed.

  Thus, according to the present invention, the reproduced sound and its dry sound are output from the position corresponding to the sounding position at the time of measurement, so that the sense of localization of the sound image can be increased and the feeling of reverberation can be suppressed. Therefore, it is possible to adjust the feeling of reverberation and the sense of localization of the sound image. As a result, for example, when a desired number of reverberation or sound image localization cannot be obtained due to a small number of the first speakers or a large interval between the first speakers, it is possible to take measures against this.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described.
In this specification, unless otherwise specified, “calculation processing based on a transfer function” for an audio signal means that the transfer function is subjected to convolution integration processing for the audio signal, or the transfer function is set as a filter coefficient. It means that the audio signal is filtered by an FIR (Finite Impulse Response) filter.

  First, prior to the description of the sound field reproduction method according to the embodiment, the basic technology on which the sound field reproduction as the present embodiment is based will be described with reference to FIGS. The contents of this basic technology are also described in “Japanese Patent Laid-Open No. 2002-186100” which is an earlier application of the present applicant.

In FIG. 1, a measurement environment 1 is a sound field to be reproduced in a reproduction environment 11 to be described later. In this case, for example, it may be considered as a concert hall or a live venue (live house).
The measurement environment 1 includes, for example, measurement microphones (microphones) 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h on a circumference having a radius R_bnd at a position not close to the wall of the measurement environment 1. 4i, 4j, 4k, 4l, 4m, 4n, 4o, 4p are arranged.
In this way, the circumference having the radius R_bnd where each measurement microphone 4 (ap) is arranged defines an area in which the sound field of the measurement environment 1 is reproduced in the reproduction environment 11 described later. The closed curved surface that defines the area where the sound field is reproduced in this way is referred to as a closed curved surface 10.

Each measurement microphone 4 (a-p) has its directivity directed outward in the normal direction from the center of the closed curved surface 10 as shown in the figure. In the following description of the present specification, the arrow shown on the microphone indicates the directivity.
In addition, the measurement speaker 3 is arranged as a virtual sound source at a position at a distance R_sp from the center of the closed curved surface 10. A measurement signal is supplied from the measurement signal reproduction unit 2 to the measurement speaker 3. As this measurement signal, a TSP (Time Streched Pulse) signal for impulse response measurement, which will be described later, is output.
Note that the measurement speaker 3 is provided to reproduce a virtual speaker in a reproduction environment 11 to be described later, and therefore the directivity and frequency characteristics thereof are assumed to be audible to the listener in the reproduction environment 11. desirable.

In the measurement environment 1, the measurement signal TSP is supplied to the measurement speaker 3 so that the measurement sound output from the measurement speaker 3 is input to each measurement microphone 4 (ap). FIG. 1 schematically shows a voice path from the measurement speaker 3 to the measurement microphone 4a.
The sound signal detected by each measurement microphone 4 (ap) is supplied to an impulse response measurement device (not shown), and here, based on the sound pressure of the sound detected by each measurement microphone 4, the measurement is performed. Impulse responses corresponding to the measurement speakers 3 to the respective measurement microphones 4 (ap) are measured. The impulse response may be about 5 to 10 seconds for a large hole or the like, but may be shorter in a small hole or a hole with little sound. By this measurement, a transfer function based on each impulse response can be obtained. That is, FIG. 1 shows a voice path when the transfer function Ha corresponding to the measurement microphone 4a is obtained. Although not shown, the transfer functions Hb to Hp corresponding to the measurement microphone 4b to the measurement microphone 4p can be similarly obtained.

The impulse response measurement may be performed for each measurement microphone, or may be performed simultaneously for all the measurement microphones 4 (ap). Further, the measurement signal is not limited to the TSP signal, and pseudo random noise, music signal, or the like may be used.
Alternatively, only one measurement microphone 4 may be used, and the measurement microphones 4a to 4p in the drawing may be sequentially arranged for measurement.
In the following description, the transfer function from the measurement speaker to the measurement microphone in the measurement environment 1 is represented by “H”.

  In this way, in the measurement environment 1, the transfer functions Ha, Hb, Hc, Hd... Hp corresponding to the respective measurement microphones 4a, 4b, 4c, 4d. By using these transfer functions Ha to Hp, the sound field of the measurement environment 1 can be reproduced in an environment (reproduction environment 11) different from the measurement environment 1.

FIG. 2 shows a configuration of a reproduction sound reproduction system (reproduction signal generation device) in a reproduction environment.
In the reproduction signal generation device 5, the audio reproduction unit 6 can output an arbitrary audio signal S. The audio signal S output from the audio reproduction unit 6 is supplied to the calculation units 7a, 7b, 7c, 7d... 7n, 7o, 7p. Transfer functions to which the same subscripts (alphabetical characters) are attached to the individual calculation units 7 (ap) are transferred to the respective computation units 7 (ap) in correspondence with the measurement microphones 4a to 4p as described above. H is set, and each calculation unit 7 performs a calculation process on the supplied audio signal S based on the set transfer function H. As a result, the reproduction signals SHa, SHb, SHc, SHd... SHn, SHo, SHp in which the impulse response corresponding to the transfer function is convoluted with respect to the audio signal S are obtained from each arithmetic unit 7 (ap). Is output.
As described above, the operation of each calculation unit 7 can also be realized by an FIR filter in which each set transfer function (impulse response) is set as a filter coefficient. The same applies to all “calculation units” described later.

  Each reproduction signal SH (ap) is supplied to reproduction speakers 8a, 8b, 8c, 8d... 8n, 8o, 8p arranged in the reproduction environment 11. Thereby, each reproduction speaker 8 (ap) outputs sound based on the reproduction signal SH (ap) based on the transfer function H (ap) in the measurement environment 1.

FIG. 3 is a schematic diagram for explaining the reproduction environment 11.
The reproduction environment 11 is, for example, an anechoic room or a studio with little reverberation.
The reproduction speakers 8 (ap) shown in FIG. 2 are arranged in the reproduction environment 11. In this case, the reproduction speaker 8 (ap) is arranged on the outer periphery of the closed curved surface 10 formed by the radius R_bnd, corresponding to the arrangement position of the measurement microphone 4 (ap) shown in FIG. The That is, the arrangement positions of the reproduction speakers 8 (ap) and measurement microphones 4 (ap) with the same subscript (alphabet) correspond to each other. That is, these reproduction speakers 8 (ap) in the reproduction environment 11 are arranged so as to obtain a geometrically equivalent arrangement relationship with the measurement microphones 4 (ap) in the measurement environment 1. .

In addition, each reproduction speaker 8 (ap) is arranged toward the inner side in the normal direction of the closed curved surface 10. That is, each reproduction speaker 8 (ap) is disposed in the opposite direction to each measurement microphone 4 (ap) disposed on the closed curved surface 10 in the measurement environment 1.
Note that the closed curved surface 10 in the measurement environment 1 and the closed curved surface 10 in the reproduction environment 11 are closed curved surfaces that exist in different spaces, but here are geometrically equivalent closed curved surfaces formed with the same radius. Therefore, the same reference numerals are attached for convenience.

  Then, by supplying and outputting the reproduction signal SH (ap) as shown in FIG. 2 from these reproduction speakers 8 (ap), the closed curved surface 10 in the reproduction environment 11 is supplied. 1 feels that the sound field when the audio signal S is reproduced from the measurement speaker 3 shown in FIG. 1 is reproduced on the outside of the closed curved surface 10 of the reproduction environment 11. Can do.

Here, when there is no sound source in a certain closed curved surface, in order to accurately reproduce the sound field in another place, the sound pressure on the outer periphery of the closed curved surface and the normal direction of the original sound field and the reproduced sound field are It is known that the particle velocities need to be matched (refer to “Literature: Electronic Systems and Digital Processing” edited by the Institute of Electronics, Information and Communication Engineers (Corona)) That is, the continuation of the wavefront of the sound input from the outside of the closed curved surface in the original sound field may be reproduced inside the closed curved surface in the reproduced sound field.
Specifically, an infinite number of bidirectional microphones are installed on a closed curved surface, and the sound pressure and particle velocity at each installation point are measured. For this reason, innumerable measurement microphones are installed in the normal direction in the closed curved surface 10 in the measurement environment 1, and innumerable reproduction microphones corresponding to these measurement microphones in the closed curved surface 10 in the reproduction environment 11. By arranging the speaker, when the viewing position is the inside of the closed curved surface 10 in the reproduction environment 11, the listener can obtain the same feeling of localization and reverberation as in the closed curved surface 10 of the measurement environment 1. In addition, a virtual sound image can be perceived at the position of the measurement speaker 3 that is not in the reproduction environment 11. In other words, at any listening position inside the closed curved surface 10 of the reproduction environment 11, a sound field feeling equivalent to that of the measurement environment 1 can be obtained on the outside.
However, as described above, it is difficult to actually realize this because it requires an infinite number of microphones and reproduction speakers. Accordingly, the present applicant pays attention to the fact that the output of a directional microphone, for example, a unidirectional microphone, includes sound pressure and particle velocity components, and a finite number of unidirectional microphones and a corresponding number of unidirectional microphones. Experiments have confirmed that almost the same acoustic effect can be obtained with the reproduction speaker.

In this way, the sound field in the measurement environment 1 such as a hall can be reproduced in the reproduction environment 11 that is an anechoic chamber or the like.
Here, according to this, if the impulse response is measured once in the measurement environment 1 as shown in FIG. 1, the measurement data (transfer function) is used thereafter, so that the reproduction environment 11 or the like is used. In an environment other than the measurement environment 1, the sound field of the measurement environment 1 can be simulated at any time.
In this case, according to the configuration shown in FIG. 2, since the sound reproduced in the sound field reproduced in this way can be any sound, any sound is reproduced in the measured hall. Can be reproduced as being performed (any performance was performed).

  By the way, according to the sound field reproduction method described so far, as described above, for example, the number of microphones 4 used in the measurement environment 1, that is, the number of speakers 8 used in the reproduction environment 11 is extremely small. When the interval between the four speakers, that is, the interval between the speakers 8 is excessively wide, there may be a case where a reverberation feeling / localization feeling cannot be obtained. Specifically, a sound with blurred reverberation and a blurred outline as heard in a large hall will be reproduced.

Therefore, in the present embodiment, a separate speaker is provided at a position corresponding to the position (sound generation position) where the measurement speaker 3 is arranged in the measurement environment 1 as the position of the virtual sound image shown in FIG. It is assumed that the audio signal S based on the reproduction signal SH is output without being subjected to arithmetic processing by the arithmetic unit 7. That is, by outputting the audio signal S as it is from the sound image position in the reproduction environment 11 in this way, the sense of localization of the sound image is increased and the reverberation feeling is suppressed.
As such a technique, the following first to third embodiments are proposed.

<First Embodiment>

1st Embodiment proposes the method corresponding to the case where one sound image is assumed like the method of the said FIGS. 1-3.
In the first embodiment, the measurement performed in the measurement environment 1 is the same as that described with reference to FIG. 1, and a description thereof is omitted here.

FIG. 4 schematically shows a reproduction operation in the reproduction environment 11 when the method of the first embodiment is adopted.
First, in the reproduction environment 11 in this case, the dry sound output speaker 9 (second speaker) is arranged at the position of the virtual sound image shown in FIG. 3 as shown in the figure. That is, the relationship of the position (sound generation position) of the measurement speaker 3 with respect to the closed curved surface 10 in the measurement environment 1 and the closed curved surface 10 (formed with a plurality of reproduction speakers 8 arranged) in the reproduction environment 11. The dry sound output speaker 9 is arranged so that the relationship with the arrangement position of the dry sound output speaker 9 is equivalent.
In this case, the reproduction signals SHa to p are output from the reproduction speakers 8a to 8p (first speakers) arranged on the closed curved surface 10 as in the case of FIG. Further, in this case, the sound signal S based on the reproduction signal SH is output from the dry sound output speaker 9.

For confirmation, FIG. 5 shows the internal configuration of the reproduction signal generation device 15 in the case of the first embodiment.
As the reproduction signal generation device 15, as can be seen in comparison with the reproduction signal generation device 5 of FIG. 2, the sound signal S from the sound reproduction unit 6 is dry-sound together with each calculation unit 7 (ap). The output speaker 9 is also branched and output.

  According to the first embodiment, the sound signal S as a dry sound based on the reproduction signal SH is output from the position of the sound image to be localized. Thus, the sound as the dry sound output from the sound image position is spatially mixed with the reproduction signal SH output from each reproduction speaker 8 within the closed curved surface 10. As a result, the localization of the sound image can be increased and the reverberation can be suppressed.

As described above, according to the first embodiment, the sound signal S is output from the dry sound output speaker 9, thereby making it possible to adjust reverberation and sound image localization. As a result, for example, when a desired number of reverberation or sound image localization cannot be obtained due to a small number of reproduction speakers 8 (measuring microphones 4) or a large interval between them, it is possible to take measures against this. it can.

<Second Embodiment>

The second embodiment corresponds to the case where a plurality of sound images to be localized are assumed.
FIG. 6 schematically shows the measurement performed in the measurement environment 1 in the case of the second embodiment.
First, in this case, in the measurement environment 1 in which measurement microphones 4a to 4p similar to those in FIG. 1 are arranged, a plurality of measurement speakers 3-1, 3-2, 3-3, 3-4 as shown in the figure. Are arranged at different locations outside the closed curved surface 10. Here, the arrangement position of the measurement speaker 3-1 is represented as Position1, and the arrangement position of the measurement speaker 3-2 is represented as Position2. Similarly, the arrangement positions of the measurement speaker 3-3 and the measurement speaker 3-4 are Position 3 and Position 4, respectively.
That is, the sound image is localized in each of Position 1 to Position 4.

Then, the measurement signal TSP is supplied to each measurement speaker 3 to perform measurement.
At this time, each measurement microphone 4 (ap) detects an output audio signal for each measurement speaker 3. The audio signal for each of these measurement speakers 3 obtained by each measurement microphone 4 is again supplied to an impulse response measurement device (not shown), whereby each measurement speaker 3 (3-1 to 3-4) is supplied. To the measurement microphones 4 (a to p) corresponding to the impulse responses are measured, and based on the results, transfer functions corresponding to the measurement microphones 3 to the measurement microphones 4 can be obtained. .
For example, in FIG. 6, a path for obtaining a transfer function Ha-1 corresponding to the measurement microphone 3-1 to the measurement microphone 4a and a transfer function Hb-1 corresponding to the measurement speaker 3-1 to the measurement microphone 4b are obtained. This is shown schematically. Similarly, a path for obtaining a transfer function Ha-3 corresponding to the measurement microphone 3-3 to the measurement microphone 4a and a transfer function Ho-3 corresponding to the measurement speaker 3-3 to the measurement microphone 4o. Is also shown schematically.

In this way, according to the measurement signal TSP output for each measurement speaker 3, transfer functions Ha-1 to Hp-1 corresponding to the measurement microphones 3a to 4p are measured. Transfer function Ha-2 to Hp-2 corresponding to each measurement microphone 4a-p from the measurement speaker 3-2, and transfer function Ha-3 corresponding to each measurement microphone 4a to p from the measurement speaker 3-3. Transfer functions Ha-4 to Hp-4 corresponding to Hp-3 and the measurement microphones 3-4 to the measurement microphones 4a to 4p can be obtained.
The measurement of the impulse response in this case is desirably performed by outputting the measurement signal TSP for each measurement speaker 3 so that the sound from the measurement speakers 3 of different Positions is not mixed. In addition to arranging a plurality of measurement speakers 3, one measurement speaker 3 may be arranged in each position sequentially.

FIG. 7 shows reproduction signal generation for generating a reproduction signal SH based on these transfer functions Ha-1 to Hp-1, Ha-2 to Hp-2, Ha-3 to Hp-3, and Ha-4 to Hp-4. The structure of the apparatus 20 is shown.
The reproduction signal generating device 20 is configured to reproduce a sound that is different from each other for each of a plurality of sound image positions (Position 1 to Position 4). 6-2, 6-3, 6-4.
Also in this case, each audio reproduction unit 6 can output an arbitrary audio signal S. Here, the audio signal S output from each audio reproduction unit 6 is shown as audio signals S1, S2, S3, and S4 corresponding to the respective Position numbers.

In this case, four sets corresponding to each of Position 1 to Position 4 are provided as the calculation unit 7. That is, arithmetic units 7a-1 to 7p-1 corresponding to Position1, arithmetic units 7a-2 to 7p-2 corresponding to Position2, arithmetic units 7a-3 to 7p-3 corresponding to Position3, arithmetic units corresponding to Position4 7a-4 to 7p-4 are provided.
For the calculation units 7a-1 to 7p-1 corresponding to Position1, transfer functions Ha-1 to Hp corresponding from the measurement speaker 3-1 to each measurement microphone 4 (ap) as shown in the figure. -1 is set. These arithmetic units 7a-1 to 7p-1 perform arithmetic processing based on the set transfer function H on the audio signal S1 input from the audio reproducing unit 6-1, respectively, and reproduce signals SHa-1 to SHp. -1 is output. Thus, first, a reproduction signal for reproducing the sound image of the measurement speaker 3-1 (Position 1) (including reverberation of course) is obtained.

For the calculation units 7a-2 to 7p-2 corresponding to Position 2, transfer functions Ha-2 to Hp-2 corresponding to the measurement microphones 3-2 to the measurement microphones 4 (a to p) are provided. Are set, and the calculation units 7a-2 to 7p-2 perform calculation processing based on the set transfer function H on the audio signal S2 input from the audio reproduction unit 6-2, respectively, and thereby reproduce the reproduction signal SHa-. 2 to SHp-2 are output. As a result, a reproduction signal for reproducing the sound image of the measurement speaker 3-2 (Position 2) is obtained.
Similarly, in the calculation units 7a-3 to 7p-3, transfer functions Ha-3 to Hp-3 corresponding to the measurement microphones 3-3 to the measurement microphones 4 (a to p) are set, respectively, An arithmetic process based on the set transfer function H is performed on the audio signal S3 input from the reproduction unit 6-3, and reproduction signals SHa-3 to SHp-3 are output. As a result, a reproduction signal for reproducing the sound image of the measurement speaker 3-3 (Position 3) is obtained.
Further, in the calculation units 7a-4 to 7p-4, transfer functions Ha-4 to Hp-4 corresponding to the measurement microphones 3-4 to the measurement microphones 4 (a to p) are set, respectively, and sound reproduction is performed. An arithmetic process based on the set transfer function H is performed on the audio signal S4 input from the unit 6-4 to output reproduction signals SHa-4 to SHp-4. As a result, a reproduction signal for reproducing the sound image of the measurement speaker 3-4 (Position 4) is obtained.

The adders 21a to 21p are provided in a one-to-one relationship with the reproduction speakers 8a to 8p. The calculation units 7a-1 to 7p-1, the calculation units 7a-2 to 7p-2, and the calculation unit 7a-3. ~ 7p-3, among the arithmetic units 7a-4 to 7p-4, the output from the arithmetic unit 7 with the same subscript (alphabet) is input and added to reproduce the same subscript Is supplied to the speaker 8.
That is, for example, the adder 21a inputs the four reproduction signals SHa-1, SHa-2, SHa-3, and Sha-4 from the arithmetic units 7a-1, 7a-2, 7a-3, and 7a-4, A reproduction signal Sha-1234 obtained by adding these is supplied to the reproduction speaker 8a. As a result, the reproduced sound corresponding to the route from all the positions shown in FIG. 6 to the measurement microphone 4a can be output from the speaker 8a.
For example, the adder 21p inputs the four reproduction signals SHp-1, SHp-2, SHp-3, and SHp-4 from the calculation units 7p-1, 7p-2, 7p-3, and 7p-4, A reproduction signal SHp-1234 obtained by adding these is supplied to the reproduction speaker 8p. As a result, the reproduced sound corresponding to the path from all the positions shown in FIG. 6 to the measurement microphone 4p can be output from the speaker 8p.

  Such addition of the reproduction signal SH is similarly performed in the other adders 21b to 21o, so that in the corresponding speakers 8b to 8o, the paths from all the positions to the corresponding measurement microphones 4 are similarly provided. Corresponding reproduction sound can be output. Note that the reproduction signal SH generated by the addition of each adder 21 is indicated by adding “−1234” to the corresponding subscript (alphabet).

  And also as the reproduction signal generation apparatus 20 of 2nd Embodiment, while supplying the audio | voice signal S from each audio | voice reproduction | regeneration part 6 to each calculating part 7, it also branches and supplies with respect to the dry sound output speaker 9. To be done. That is, the audio signal S1 from the audio reproduction unit 6-1 is branched and supplied to the dry sound output speaker 9-1, and the audio signal S2 from the audio reproduction unit 6-2 is supplied to the dry sound output speaker 9-2. Is also branched and supplied. Similarly, the audio signal S3 from the audio reproduction unit 6-3 is branched and supplied to the dry sound output speaker 9-3, and the audio signal S4 from the audio reproduction unit 6-4 is supplied to the dry sound output speaker 9-3. 4 is also configured to be branched and supplied.

FIG. 8 schematically shows the sound field reproduction operation performed in the reproduction environment 11 in this case.
First, even in this case, in the reproduction environment 11, the reproduction speakers 8a to 8p are arranged so as to obtain a geometrically equivalent arrangement relationship with the measurement microphones 4a to 4p in the measurement environment 1 shown in FIG. It is arranged. Therefore, the closed curved surface formed by arranging the reproduction speakers 8a to 8p is shown as the closed curved surface 10 in this case as well.

Further, the above-described dry sound output speakers 9-1, 9-2, 9-3, and 9-4 are arranged corresponding to Position1, Position2, Position3, and Position4 in the measurement environment 1 shown in FIG. Therefore, the dry sound output speaker 9-1 is disposed at a position corresponding to Position 1 shown in FIG. 6, and the dry sound output speaker 9-2 is disposed at a position corresponding to Position 2 shown in FIG. . Further, the dry sound output speaker 9-3 is arranged at a position corresponding to Position 3 shown in FIG. 6, and the dry sound output speaker 9-4 is arranged at a position corresponding to Position 4 shown in FIG.
In other words, the dry sound output speakers 9-1 to 9-4 are such that their positional relationship with respect to the closed curved surface 10 in the reproduction environment 11 is the respective measurement speakers with respect to the closed curved surface 10 in the measurement environment 1 shown in FIG. 3 (respective Positions) are arranged so as to have the same positional relationship.

As can be understood from the description with reference to FIG. 7, the reproduction speakers 8a to 8p on the closed curved surface 10 are connected to the respective measurement microphones 4 from the respective measurement speakers 3 (respective Positions). Reproduction signals SHa-1234 to SHp-1234 respectively generated correspondingly are output.
As a result, the listener inside the closed curved surface 10 in the reproduction environment 11 surrounded by the reproduction speakers 8a to 8p is from each of the measurement speakers 3 (Position 1, Position 2, Position 3, and Position 4) shown in FIG. It can be felt that the sound field when reproducing the sound is reproduced in a pseudo manner outside the closed curved surface 10. In other words, this makes it possible to reproduce (localize) a sound image at each of Position 1, Position 2, Position 3, and Position 4, and also to reproduce reverberation specific to the measurement environment 1.

  Here, according to the configuration of the reproduction signal generation device 15 illustrated in FIG. 7, separate audio can be output independently for each of Position 1, Position 2, Position 3, and Position 4. According to this, by outputting different Player sounds such as vocals, drums, guitars, keyboards (keyboard instruments) etc. for each Position, vocals (Player1) for Position1, drums (Player2) for Position2, The sound image of the appropriate player can be localized at the appropriate position, such as guitar (Player 3) for Position 3 and keyboard (Player 4) for Position 4.

Also in this case, the sound signal S based on the reproduction signal SH is output from the dry sound output speaker 9. In other words, in this case, the dry sound output speakers 9-1, 9-2, 9-3, and 9-4 are arranged at positions corresponding to Position 1, Position 2, Position 3, and Position 4, respectively. Audio signal S1 from the dry sound output speaker 9-1, audio signal S2 from the dry sound output speaker 9-2, and dry sound output speaker 9-3 so that the dry sound as the sound from the sound is output. Outputs an audio signal S3 and an audio signal S4 from the dry sound output speaker 9-4.
Thus, by outputting the corresponding audio signal S from each dry sound output speaker 9, the reverberation feeling and the sound image localization feeling can be adjusted in this case as in the case of the first embodiment. .

In the second embodiment, four sound images are assumed. However, the number of sound images to be assumed is not limited to this.

<Third Embodiment>

The third embodiment is a method corresponding to a case where a three-dimensional closed curved surface 10 is assumed.
Here, when assuming a sound reproduction system using a multi-channel speaker as shown in FIG. 3 above, content that makes a sound image from above or below be perceived as content to be reproduced is created. Can be considered.
However, when the closed curved surface 10 is a flat surface as shown in FIG. 3, the plane is also defined as an area for reproducing the sound field. Therefore, the sound image from above or below is given to the listener in the closed curved surface 10. Is difficult to perceive clearly.

  Therefore, in the third embodiment, the closed curved surface 10 is defined as a solid as described above, and a plurality of positions on a plurality of horizontal planes formed in the closed curved surface 10 by the solid are illustrated in FIG. The sound field reproduction is performed by the same method as described in FIG.

  In the third embodiment, it is assumed that only one sound image is localized as in the first embodiment, and only one dry sound output speaker 9 is arranged accordingly. To do. In this case, the relationship between the arrangement position of the measurement speaker 3 with respect to the closed curved surface 10 in the measurement environment 1 and the arrangement position of the dry sound output speaker 9 with respect to the closed curved surface 10 in the reproduction environment 11 are made equal. The arrangement of the dry sound output speaker 9 and the output of the sound signal S as the dry sound from the dry sound output speaker 9 and further the adjustment of the reverberation feeling and the localization of the sound image can be performed thereby. Since this is the same as in the case of the first embodiment, a description thereof is omitted here.

  Also, the third embodiment can be configured to localize a plurality of sound images as in the second embodiment. Even in this case, the relationship between the arrangement position of each measurement speaker 3 with respect to the closed curved surface 10 in the measurement environment 1 and the arrangement position of each dry sound output speaker 9 with respect to the closed curved surface 10 in the reproduction environment 11 are equivalent. The plurality of dry sound output speakers 9 are arranged in this manner, and the sound signal S for each sound image as the corresponding dry sound is output from each of the dry sound output speakers 9, and further, the reverberation feeling The adjustment of the sense of localization of the sound image is the same as in the case of the second embodiment, and will not be described.

FIG. 9 schematically shows a state of measurement in the measurement environment 1 when sound field reproduction is performed as the third embodiment.
First, as shown in the drawing, in this case, a cylindrical shape is defined as the three-dimensional closed curved surface 10, and the upper horizontal plane 10-1 and the middle horizontal plane 10 shown in the drawing are shown as a plurality of horizontal planes formed in the closed curved plane 10. -2, The horizontal surface by three circles of the lower horizontal surface 10-3 is defined.
In this figure, the vertical direction is indicated by a double arrow in the figure, and a plane perpendicular to the vertical direction is called a horizontal plane. The direction perpendicular to the vertical direction is called the horizontal direction.

  A plurality of measurement microphones 4 are arranged on the outer circumferences of the upper horizontal plane 10-1, the middle horizontal plane 10-2, and the lower horizontal plane 10-3. In this case, ten measurement microphones 4 by the measurement microphones 4a to 4j are arranged on each horizontal plane. The measurement microphone 4 arranged on the upper horizontal plane 10-1 is represented by adding “−1” at the end, such as measurement microphones 4a-1 to 4j-1. Similarly, the measurement microphone 4 arranged on the middle horizontal plane 10-2 is indicated by attaching “-2” to the measurement microphones 4a-2 to 4j-2 and arranged on the lower horizontal plane 10-3. The measurement microphone 4 is represented by “−3”, such as measurement microphones 4a-3 to 4j-3.

The measurement microphones 4a-1 to 4j-1, the measurement microphones 4a-2 to 4j-2, and the measurement microphones 4a-3 to 4j-3 are respectively the upper horizontal plane 10-1 and the middle horizontal plane 10-2. And arranged so as to be directed outward in the normal direction from the center of the lower horizontal plane 10-3.
In this case, the same subscript (alphabet) is used as each of the measurement microphones 4a-1 to 4j-1, the measurement microphones 4a-2 to 4j-2, and the measurement microphones 4a-3 to 4j-3. The attached items are arranged so as to be in the same row in the vertical direction in the figure. That is, for example, the measurement microphone 4a-1, the measurement microphone 4a-2, and the measurement microphone 4a-3 are arranged in the same row in the vertical direction in the figure.

  In addition, in this case as well, in the measurement environment 1, the measurement speaker 3 is disposed at a required position outside the closed curved surface 10 as the sound generation position. Here, for example, assuming a concert in a hall or the like, the sound generation position is assumed to be a player's position on the stage, and the closed curved surface 10 is assumed to be a space on the audience seat side. Accordingly, the measurement speaker 3 is disposed outside the closed curved surface 10 in the horizontal direction.

  Then, the measurement signal TSP is output from the measurement speaker 3 in the same manner as in the case of FIG. 1, and this is detected for each measurement microphone 4. Also in this case, the sound reflected by the wall, floor, and ceiling arrives at each measurement microphone 4 together with the direct sound from the measurement speaker 3, and thereby the sound including the spatial information of the measurement environment 1 is obtained. Is detected.

The audio signal detected for each measurement microphone 4 is again supplied to an impulse response measuring device (not shown), and the impulse response corresponding to each measurement microphone 4 is measured. As a result, a transfer function H corresponding to each measurement microphone 3 from the measurement speaker 3 is obtained.
In FIG. 4, as an example, the transfer function H1-a corresponding to the measurement microphone 4a-1, the transfer function H2-a corresponding to the measurement microphone 4a-2, and the transfer corresponding to the measurement microphone 4a-3. The function H3-a is schematically shown.
As shown here, transfer functions H1-a to H1- for transfer functions H corresponding to the respective measuring microphones 4 (4a-1 to 4j-1) arranged on the upper horizontal plane 10-1. “1” is added as an H subscript, such as j. Similarly, the transfer function H corresponding to each of the measurement microphones 4 (4a-2 to 4j-2) arranged on the middle horizontal plane 10-2 is subscript “2” as transfer functions H2-a to H2-j. And the transfer functions H corresponding to the respective measurement microphones 4 (4a-3 to 4j-3) arranged on the lower horizontal plane 10-3 are referred to as transfer functions H3-a to H3-j. In this way, the subscript “3” is added.

FIG. 10 shows a cross-sectional view of the solid closed curved surface 10 shown in FIG. 9 when cut in the vertical direction.
Here, in the third embodiment as described above, three horizontal planes in which a plurality of measurement microphones 4 are arranged are defined. According to this, however, the closed plane is closed by the plane shown in FIG. This corresponds to increasing the curved surface 10 one by one up and down. That is, if the middle horizontal plane 10-2 plays the same role as that shown in FIG. 1 among these three horizontal planes, the upper horizontal plane 10-1 and the lower horizontal plane 10-3 located at the upper and lower stages are It can be considered that the sound input from above and the sound input from below are reproduced for the three-dimensional closed curved surface 10.

At this time, in this embodiment, a unidirectional microphone is used as each measurement microphone 4. Accordingly, in order to input voice from above in the upper horizontal plane 10-1 and voice from below in the lower horizontal plane 10-3, the upper measurement microphone 4-1 is somewhat The lower measurement microphone 4-3 facing upward is directed slightly downward.
In addition, the middle horizontal plane 10-2 is directed to the horizontal direction without being inclined in the vertical direction in order to play the same role as in the case of FIG. 1 as described above.

When the direction in which each of the measurement microphones 4-1, 4-2, and 4-3 is defined as described above, the sound field boundary between the closed curved surface 10 and the outside thereof is an image indicated by a one-dot chain line in the drawing. . That is, when the upper measurement microphone 4-1 is tilted upward, the upper portion of the sound field boundary has a curved shape that is inclined inward of the closed curved surface 10. Further, when the lower measurement microphone 4 is tilted downward, the lower portion of the sound field boundary is similarly curved so as to be inclined inward of the closed curved surface 10. Moreover, since each measurement microphone 4-2 in the middle stage is directed in the horizontal direction, the middle stage portion of the sound field boundary has a linear shape in the vertical direction.
FIG. 11 shows a perspective view of the sound field boundary image of the closed curved surface 10 formed in this way.

FIG. 12 schematically shows the state of the reproduction environment 11 in which the sound field is reproduced based on the measurement result in the measurement environment 1 described with reference to FIG.
As shown in the figure, in this case as well, the same number of reproduction speakers 8 arranged in the reproduction environment 11 as the measurement microphones 4 arranged in the measurement environment 1 are arranged.
The reproduction speakers 8 arranged on the outer periphery of the upper horizontal surface 10-1 of the closed curved surface 10 in the reproduction environment 11 are appended with “-1” at the end, such as reproduction speakers 8a-1 to 8j-1. To express. The reproduction speakers 8 arranged on the outer circumference of the middle horizontal plane 10-2 are reproduced for the reproduction speakers 8a-2 to 8j-2, and the reproduction speakers 8 arranged on the outer circumference of the lower horizontal plane 10-3 are reproduced. Speakers 8a-3 to 8j-3 are denoted by "-2" and "-3", respectively.

The reproduction speakers 8 a-1 to 8 j-1 on the upper horizontal plane 10-1 are arranged with the same subscripts as the measurement microphones 4 a-1 to 4 j-1 arranged in the measurement environment 1. Are arranged to be the same.
Further, the reproduction speakers 8a-2 to 8j-2 on the middle horizontal plane 10-2 are also arranged with the same subscripts as those of the measurement microphones 4a-2 to 4j-2 arranged in the measurement environment 1. The reproduction speakers 8a-3 to 8j-3 on the lower horizontal plane 10-3 are arranged in the same relationship with the measurement microphones 4a-3 to 4j-3 arranged in the measurement environment 1. Arranged so that the same subscripts are placed in the same position.
In other words, the measurement microphones 4 arranged in the measurement environment 1 shown in FIG. 9 and the reproduction speakers 8 arranged in the reproduction environment 11 have a geometrically equivalent arrangement relationship. Be placed.

  The closed curved surface 10, the upper horizontal plane 10-1, the middle horizontal plane 10-2, and the lower horizontal plane 10-3 in the reproduction environment 11 are the closed curved surface 10, the upper horizontal plane 10-1, the middle horizontal plane 10-2, and the lower horizontal plane in the measurement environment 1. Although they exist in a space different from the horizontal plane 10-3, these are also geometrically equivalent closed surfaces or horizontal planes, and are given the same reference numerals for convenience.

  Also in the reproduction environment 11 in this case, the dry sound output speaker 9 is arranged as illustrated.

Here, the configuration of the reproduction signal generation device of the third embodiment is almost the same as the configuration of the reproduction signal generation device 15 of the first embodiment shown in FIG. However, the number of calculation units 7 varies depending on the number of reproduction speakers 8 used. Specifically, as the reproduction signal generation device in the case of the third embodiment, each measurement microphone 4 (4a-1 to 4j) arranged on the upper horizontal plane 10-1 acquired by the measurement of FIG. -1) and transfer functions H2-a to H1-j corresponding to the measurement microphones 4 (4a-2 to 4j-2) arranged on the middle horizontal plane 10-2. -J, and calculation units 7 (7a-1 to 7a-1 to 7) that respectively set transfer functions H3-a to H3-j corresponding to the respective measurement microphones 4 (4a-3 to 4j-3) on the lower horizontal plane 10-3 7j-1, 7a-2 to 7j-2, 7a-3 to 7j-3) are provided, and the audio signal S from the audio reproduction unit 6 is supplied to them.
And the audio | voice signal S (namely, reproduction) which performed the arithmetic processing based on the transfer function H each set in these calculating part 7a-1 to 7j-1, 7a-2 to 7j-2, 7a-3 to 7j-3, respectively. Signals Sa-1 to Sj-1, Sa-2 to Sj-2, Sa-3 to Sj-3) are reproduced as reproduction speakers 8a-1 to 8j-1, 8a-2 to 8j-2, 8a-3. 8j-3 is configured to be supplied to each reproduction speaker 8 having the same subscript.
Note that the reproduction signal generation device in this case also supplies the audio signal S reproduced by the audio reproduction unit 6 to the dry sound output speaker 9 in a branched manner, similarly to the reproduction signal generation device 15. Composed.

As can be understood from the configuration of such a reproduction signal generation apparatus, each reproduction speaker 8-1 arranged on the upper horizontal plane 10-1 is connected to the closed curved surface 10 from above the closed curved surface 10 in the measurement environment 1. A reproduction signal that has been subjected to arithmetic processing based on the transfer functions (Ha-1 to Hj-1) obtained for the voice input in the inner direction is output. In other words, according to this, from each reproduction speaker 8-1 arranged on the upper horizontal plane 10-1, the wave front of the sound input from the upper side of the closed curved surface 10 to the inner side of the closed curved surface 10 in the measurement environment 1 is obtained. This is equivalent to outputting the continuation toward the inside of the closed curved surface 10 in the reproduction environment 11.
Similarly, each reproduction speaker 8-2 arranged on the middle horizontal plane 10-2 and each reproduction speaker 8-3 arranged on the lower horizontal plane 10-3 have the closed curved surface 10 in the measurement environment 1 respectively. The continuation of the wave front of the sound input from the middle to the inside of the closed curved surface 10 and the continuation of the wave front of the sound input from the bottom to the inside of the closed curved surface 10 are output toward the inside of the closed curved surface 10 in the reproduction environment 11. The operation corresponding to that is obtained.
As a result, the listener in the closed curved surface 10 in the reproduction environment 11 can similarly give a reverberation feeling and a sense of localization of the sound image peculiar to the measurement environment 1 and can further perceive sound from the vertical direction. .

Further, according to such a sound field reproduction method, the listener can perceive the sound from the vertical direction at any listening position within the closed curved surface 10. In this respect, according to the above sound field reproduction, it is possible to make the listener perceive the vertical feeling of the sound in a wider range than when virtual sound is generated and the sound from the vertical direction is perceived.
In addition, such a sense of up and down sound is based on a reproduction signal generated based on an actually measured transfer function, and in this respect, a more realistic sound field reproduction can be realized than in the case of using virtual sound. There is also a merit.

It should be noted here that for confirmation, the sound field reproduction method as the third embodiment does not surround the listener directly above the speaker. It is difficult to localize a relatively small sound image in the ceiling direction.
However, since it is assumed that the sound field reproduction as exemplified in the embodiment is applied to performance in a hall or the like, the localization of the sound image in this case is as follows for the closed curved surface 10. Some think that it would be sufficient if it was possible for something in the horizontal direction.
In addition, when applied to other than that, generally, the sound image to be localized in the overhead direction of the human is, for example, the reverberation of the room, or rain, wind, thunder etc. Or it is often distributed and weak in directivity. In that sense, it can be said that even when it is assumed that the upper direction of the listener is not covered with the speaker as in the method of the third embodiment, a sufficient sense of localization in the upward direction can be provided in practice.

In addition, when the sound is set to give a sense of orientation only for the sound image set in the horizontal direction, such as for the purpose of reproducing the performance in the hall exemplified above, the upper horizontal plane 10-1 is viewed from above. It is also possible to use the reverberation effect for the lower horizontal plane 10-3 so as to give only the reverberation effect from below. In other words, the sound image localization feeling in the upward direction and the sound image localization feeling in the downward direction are not given.
In this case, the non-directional measurement microphone 4 and the reproduction speaker 8 are used as the measurement microphones 4 and the reproduction speakers 8 arranged on the upper horizontal plane 10-1 and the lower horizontal plane 10-3. You can also That is, in the measurement environment 1, a transfer function is generated based on the result of measurement with an omnidirectional microphone on the upper horizontal plane 10-1 and the lower horizontal plane 10-3. In the reproduction environment 11, reproduced signals obtained by performing arithmetic processing on the audio signal S based on these transfer functions are respectively transmitted from an omnidirectional speaker on the upper horizontal plane 10-1 and an omnidirectional speaker on the lower horizontal plane 10-3. Output.
Here, according to the omnidirectional microphone, the reverberation component in the measurement environment 1 can be captured more widely than when the unidirectional microphone is used. That is, as the transfer function, more spatial information in the measurement environment 1 can be taken in. Therefore, if a reproduced signal that is calculated based on this transfer function is output from the omnidirectional speaker as described above, Many reverberation effects can be given.

In the third embodiment, the case where a three-level horizontal plane is defined as a plurality of horizontal planes in the closed curved surface 10 is illustrated, but the horizontal plane may be two levels.
When there are two horizontal planes, one can be used as a horizontal plane for obtaining a reverberation and sound image localization in the measurement environment 1 as in the prior art, and the other is a horizontal plane for perceiving sound from above. Or a horizontal plane for perceiving sound from below. That is, according to this, the sound from at least the upper direction or the lower direction can be perceived.
Alternatively, if only the upper horizontal plane 10-1 and the lower horizontal plane 10-3 are defined, sounds from both the upper and lower sides can be perceived. However, in this case, since there is no horizontal plane corresponding to the middle horizontal plane 10-2, the sense of localization of the sound image is diminished.

Also, the horizontal plane can be more than three steps.
Here, as a method for reproducing the sound field as described in the embodiment, theoretically, a spherical surface is defined as the closed curved surface 10, and the continuation of the wave front is reproduced by an infinite number of horizontal planes on the spherical surface. Thus, an ideal sound field can be reproduced. According to this, ideally, the number of steps in the horizontal plane is increased as much as possible, and the continuation of the wavefront is reproduced at a plurality of points on a larger number of horizontal planes. It is possible to increase the fidelity. According to this, the fidelity of the sound field reproduction can be further increased by increasing the number of horizontal plane steps from three.

In the third embodiment, the measurement microphone and the reproduction speaker are arranged so as to be in the same row in the vertical direction in each horizontal plane, but need not necessarily be in the same row. For example, the measurement microphone and the reproduction speaker are arranged in the same row only in relation to the upper horizontal plane 10-1 and the lower horizontal plane 10-3, or all of the upper horizontal plane 10-1, the middle horizontal plane 10-2, and the lower horizontal plane 10-3. It can also be said that the arrangement position of the measurement microphone and reproduction speaker in the vertical direction is shifted.
Even when the measurement microphones 4 and the reproduction speakers 8 are arranged in the same row, the same effects as in the case of the same row can be obtained even when the measurement microphones 4 and the reproduction speakers 8 are arranged in the same row. Can do.

  In the third embodiment, the number of measurement microphones 4 and reproduction speakers 8 arranged on each horizontal plane is the same. However, the number of measurement microphones 4 and reproduction speakers 8 arranged on each horizontal plane is as follows. The number is not necessarily the same. Even in this case, by arranging the measurement microphones 4 and the reproduction speakers 8 so as to have a geometrically equivalent arrangement relationship, it is possible to obtain the same effect as when the number is the same.

  In the third embodiment, a cylindrical shape is defined as the closed curved surface 10. For example, a rectangular parallelepiped, a cube, and a shape by a polygonal column whose horizontal plane is a hexagon or an octagon are defined. You can also.

As mentioned above, although embodiment of this invention was described, as this invention, it should not be limited to each embodiment described so far.
For example, the number of measurement microphones 4 and the number of reproduction speakers 8 illustrated in the embodiments are merely examples, and the present invention is not limited to this.

Further, as described in the second embodiment, in the case where a plurality of virtual sound image positions are assumed, the embodiment exemplifies only the case where the number of measurement speakers 3 and the number of sound sources to be localized are the same. That is, for example, when there are four sound sources to be localized, vocal, drum, guitar, and keyboard, the vocal is localized to Position 1, the drum is positioned to Position 2, the guitar is positioned to Position 3, and the keyboard is localized to Position 4. Only the case where there is a one-to-one relationship between the number of power sources to be sounded and the number of measurement speakers 3 arranged is illustrated.
However, it is considered that it is not preferable to measure the transfer function for each position using many measurement speakers 3 when many sound sources are localized, for example, from the viewpoint of shortening the measurement time.

Therefore, the sound field reproduction of the embodiment can be avoided by adopting a method as a modified example as shown in FIGS.
13 and 14 show, as an example, a technique for reducing the number of measurement speakers 3 (Position) used for measurement to two when the number of sound sources to be localized is four.
First, as shown in FIG. 13A, in the case of four sound sources that should be localized in this case, for example, the above vocal, drum, guitar, and keyboard, recording is performed for each of these four players. The four audio signals (in this order, audio signals S1, S2, S3, and S4) are downmixed into audio signals to be output from the required two Positions. In the example of this figure, an example of narrowing down to Position 3 and Position 4 is shown, and the sound sources of Position 1 and Position 2 are mixed with the sound source of Position 3 and the sound source of Position 4, respectively.
At this time, the audio signal mixed on the Position 3 side is referred to as an audio signal S1234-3. Similarly, an audio signal mixed on the Position 4 side is referred to as an audio signal S1234-4.
Here, for the sake of confirmation, as a downmix in this case, when the audio signal S1234-3 and the audio signal S1234-4 generated thereby are output from Position3 and Position4, respectively, Position1 The sound source corresponding to is sounded by being localized at Position 1, and the sound source corresponding to Position 2 is sounded by being localized at Position 2.

In this way, the four sound sources from Position 1 to Position 4 are downmixed to those to be output from Position 3 and Position 4, and accordingly, measurement in the measurement environment 1 in this case is shown in FIG. ), The measurement speaker 3-3 and the measurement speaker 3-4 arranged in these Position 3 and Position 4 can be used.
As a result of the measurement shown in FIG. 13 (b), transfer functions Ha-3 to Hp-3 corresponding to Position 3 to each measurement microphone 4 (ap) and Position 4 to each measurement microphone 4 (a to Transfer functions Ha-4 to Hp-4 corresponding to p) are obtained.

In the reproduction environment 11 in this case, as shown in FIG. 14, the dry sound output speaker 9-3 and the dry sound output speaker 9 are respectively provided at positions corresponding to Position 3 and Position 4 in the measurement environment 1. -4. Also in this case, the reproduction speakers 8 (ap) are arranged so as to be geometrically equivalent to the measurement speakers 4 (ap) in the measurement environment 1.
After that, the sound signal S1234-3 generated by the downmix is output from the dry sound output speaker 9-3, and the sound signal S1234-4 is output from the dry sound output speaker 9-4.
In addition, the reproduction speakers 8a to 8p output the reproduction signal SH to which the corresponding subscript (alphabet) is attached among the reproduction signals SHa-34 to SHp-34.
In this case, the reproduction signals SHa-34 to SHp-34 are reproductions generated by processing the audio signal S1234-3 based on the transfer functions Ha-3 to Hp-3 obtained by the measurement of FIG. The signals SHa-3 to SHp-3 and the reproduced signals SHa-3 to SHp-3 generated by calculating the audio signal S1234-4 based on the transfer functions Ha-4 to Hp-4 are respectively of the same subscript. This is a signal generated by adding the attached ones.

Here, as described above, the downmix corresponds to Position1 when the audio signal S1234-3 and the audio signal S1234-4 generated thereby are output from Position3 and Position4, respectively. The sound source is localized and heard at Position 1, and the sound source corresponding to Position 2 is heard and localized at Position 2.
According to this, the sound field reproduction shown in FIG. 14 is performed, and localization is performed at the positions of Position 3 and Position 4, so that each sound source is also localized at Position 1 and Position 2 (not shown). be able to.
That is, as a result, the same result as that obtained when the number of sound sources and the number of measurement speakers 3 are set to 1: 1 as in the second embodiment can be obtained.

  In the above description, in this case, the dry sound output speaker 9 is also limited to 9-3 and 9-4, and the audio signal S1234-3 and S1234-4 generated by downmixing them are output. However, four dry sound output speakers 9 9-1 to 9-4 are arranged according to the number of sound sources to be localized, and the sound of each sound source (audio signal S1, audio) It is also possible to output the signal S2, the audio signal S3, and the audio signal S4).

In the embodiments described so far, particularly when the reproduction environment 11 is narrow in space, the distance from the measurement speaker 3 arranged in the measurement environment 1 to the closed curved surface 10 is the same. A case where the dry sound output speaker 9 cannot be arranged on the closed curved surface 10 in the reproduction environment 11 is also conceivable.
At this time, the direct sound component in the reproduction signal SH has a delay time corresponding to the distance from the measurement speaker 3 to each measurement microphone 4 in the measurement environment 1. If the distance from the closed curved surface 10 to the dry sound output speaker 9 in the reproduction environment 11 and the distance from the measurement speaker 3 to the closed curved surface 10 in the measurement environment 1 do not match, the reproduction output from the reproduction speaker 8 is performed. There is a risk that the sound and the dry sound output from the dry sound output speaker 9 will be shifted, making it impossible to perform proper sound field reproduction.

Therefore, when the distance between the two cannot be matched as described above, a configuration in which a delay compensation circuit 25 as shown in FIG. 15 is added may be employed.
FIG. 15 shows a configuration in which a delay compensation circuit 25 is added to the reproduction signal generation device 15 in the case of the first embodiment shown in FIG. 5 as an example.
As shown in FIG. 15, the delay compensation circuit 15 includes a supply line for the audio signal S branched from the sound reproduction unit 6 to the dry sound output speaker 9 and each calculation unit 7, and is supplied to each calculation unit 7. Provided to be inserted only in the line. That is, in this case, the configuration corresponds to the case where the distance between the closed curved surface 10 and the dry sound output speaker 9 in the reproduction environment 11 is shorter, and the reproduction signal is delayed in accordance with the distance error accordingly. It is composed.
As a result, the difference between the reproduced sound and the dry sound due to the distance error as described above can be eliminated, and an appropriate sound field reproduction can be performed.

  It should be noted that, in this way, as a method for compensating for the error between the distance of the measurement speaker 3 and the distance of the dry sound output speaker 9 with respect to the closed curved surface 10 by delay, both distances are the same as in each embodiment. Thus, a result equivalent to the case where the arrangement method is adopted is obtained. Therefore, in this sense, both methods can be regarded as equivalent.

  Of course, when the distance error is opposite to the above example (that is, when the output from the dry sound output speaker 9 is slower), the delay compensation circuit 25 is connected to the audio signal S to the dry sound output speaker 9. What is necessary is just to comprise so that it may insert only with respect to the supply line side.

In each embodiment, the description by illustration is omitted, but the sound field reproduction method of each embodiment is not limited to the use of merely reproducing the sound field, but is a sound synchronized with the image such as so-called film live. It can be applied to the usage to reproduce. In this case, a screen (display) is disposed between the dry sound output speaker 9 and the closed curved surface 10 (reproduction speakers 8a to 8p), and an image synchronized with the reproduced sound is displayed there.
According to such a configuration, the virtual sound image position matches the position of the sound source (singer, performer, etc.) projected on the screen, so that the listener (viewer) can perceive a clearer sense of localization. Can do.

It is a schematic diagram for demonstrating a measurement environment. It is the block diagram shown about the basic composition of the reproduction system of the reproduction sound in a reproduction environment. It is a schematic diagram for demonstrating reproduction environment. It is the figure which showed typically the sound field reproduction operation | movement in the reproduction environment in the case of reproducing the sound field as 1st Embodiment. It is the block diagram shown about the structure of the reproduction signal production | generation apparatus (audio | voice signal processing apparatus) of 1st Embodiment. It is the figure which showed typically about the measurement in the measurement environment in the case of performing the sound field reproduction as 2nd Embodiment. It is the block diagram shown about the structure of the reproduction signal production | generation apparatus of 2nd Embodiment. It is the figure which showed typically about the sound field reproduction operation in the reproduction environment in the case of performing the sound field reproduction as 2nd Embodiment. It is the figure which showed typically about the measurement operation in the measurement environment in the case of performing the sound field reproduction as 3rd Embodiment. It is sectional drawing when the closed curved surface in the measurement environment in the case of 3rd Embodiment is cut | disconnected in the vertical direction. It is the perspective view which showed the image of the sound field boundary in the case of 3rd Embodiment. It is the figure which showed typically about the reproduction environment in the case of performing the sound field reproduction as 3rd Embodiment. It is a figure for demonstrating mainly the measurement operation in the downmix of a sound source and a measurement environment as a figure for demonstrating the modification of embodiment. It is a figure for demonstrating mainly the sound field reproduction operation | movement in a reproduction environment as a figure for demonstrating the modification of embodiment. It is the block diagram shown about the structure of the reproduction signal production | generation apparatus of the other modification of embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Measurement environment, 2 Measurement signal reproduction | regeneration parts, 3 Measurement speakers, 4 Measurement microphones, 15, 20 Reproduction signal generators, 6 Audio reproduction parts, 7 Arithmetic parts, 8 Reproduction speakers, 9 Dry sound output speakers, 10 Closed surface, 10-1 Upper horizontal plane, 10-2 Middle horizontal plane, 10-3 Lower horizontal plane, 11 Reproduction environment, 21 Adder

Claims (8)

A pronunciation process for generating the sound from the required pronunciation position outside the closed curved surface;
A transfer function generating step for generating a transfer function for the sound reaching each of the plurality of positions from the sound generation position based on the result of measuring the sound generated in the sound generation step for each of the plurality of positions on the closed curved surface; ,
A reproduction audio signal generation step for performing a calculation process based on the transfer function generated in the transfer function generation step on the input audio signal to obtain a reproduction audio signal corresponding to each of the plurality of positions;
A reproduction audio output step of outputting the reproduction audio signal generated in the reproduction audio signal generation step from a plurality of first speakers arranged so as to have a geometrically equivalent positional relationship with the plurality of positions; ,
Dry sound that outputs the sound signal from the second speaker arranged for the plurality of first speakers so as to have the same positional relationship as the sound generation position with respect to the closed curved surface without being subjected to the arithmetic processing. An output process;
A sound field reproduction method characterized by comprising: The pronunciation process includes
Sounds from each of a plurality of pronunciation positions outside the closed curved surface,
The transfer function generation step includes:
For voices reaching each of the plurality of positions from each of the plurality of sound generation positions based on a result of measuring sounds from the plurality of sound generation positions sounded in the sound generation step for each of the plurality of positions on the closed curved surface. Generate a transfer function of
In the reproduction audio signal generation step,
The plurality of sound signals corresponding to each of the plurality of sound generation positions are input, and the sound signals for each sound generation position are subjected to arithmetic processing based on the transfer function generated in the transfer function generation step, thereby For each sound generation position, a reproduction audio signal corresponding to each of the plurality of positions is obtained,
In the reproduction audio output step,
A plurality of reproduction audio signals corresponding to each of the plurality of positions obtained by the reproduction audio signal generation step for each sound generation position are arranged so as to have a geometrically equivalent positional relationship with the plurality of positions. Each of the outputs from the first speaker,
The dry sound output step includes
Audio signals corresponding to the respective sound generation positions are respectively output from the plurality of second speakers arranged with respect to the plurality of first speakers so as to have the same positional relationship as that of the plurality of sound generation positions with respect to the closed curved surface. Output without performing the arithmetic processing,
The sound field reproduction method according to claim 1, wherein: The pronunciation process includes
Sound is produced from the pronunciation position outside the closed surface by a solid,
The transfer function generation step includes:
Each of the plurality of positions on the horizontal plane from the sounding position based on the result of measuring the sound produced in the sounding step for each of a plurality of positions on the outer circumference of each of the plurality of horizontal planes in the closed curved surface. Generate a transfer function for the speech that reaches
In the reproduction audio signal generation step,
The input audio signal is subjected to a calculation process based on the transfer function generated in the transfer function generation step, and a reproduction audio signal corresponding to each of the plurality of positions on the horizontal plane is obtained.
In the reproduction audio output step,
The reproduction audio signals generated in the reproduction audio signal generation step are respectively output from the plurality of first speakers arranged so as to have a geometrically equivalent positional relationship with the plurality of positions on the respective horizontal planes. To be,
The sound field reproduction method according to claim 1, wherein: In the transfer function generation step,
The sound produced in the sound production step is measured using a unidirectional microphone directed from the horizontal plane center to the outside in the normal direction,
In the reproduction audio output step,
As the plurality of speakers, the reproduction audio signal is output by a unidirectional speaker arranged to be opposite to the direction of each of the unidirectional microphones arranged in the sound generation step.
The sound field reproduction method according to claim 3, wherein:   The sound field reproduction method according to claim 3, wherein the horizontal plane has three or more steps. Furthermore, it should be output from the first speaker in accordance with an error between the distance to the sound generation position with respect to the closed curved surface and the distance to the second speaker with respect to the closed curved surface where the plurality of first speakers are arranged. A delay time adjusting step of adjusting a delay time of the audio signal for reproduction or the audio signal to be output from the second speaker;
The sound field reproduction method according to claim 1, wherein: A transfer function for the sound that arrives at each of the plurality of positions from the sound generation position, generated based on the result of measuring the sound generated from the required sound generation position outside the closed surface for each of a plurality of positions on the closed surface A plurality of reproduction audio signals corresponding to each of the plurality of positions generated by performing arithmetic processing on the audio signal based on the plurality of positions so as to have a geometrically equivalent positional relationship with the plurality of positions. An audio output process for reproduction output from each of the first speakers;
A dry output unit that outputs the audio signal from the second speakers arranged for the plurality of first speakers so as to have the same positional relationship as the sound generation position with respect to the closed curved surface without performing the arithmetic processing. Audio output process;
An audio signal processing method comprising: A transfer function for the sound that arrives at each of the plurality of positions from the sound generation position, generated based on the result of measuring the sound generated from the required sound generation position outside the closed surface for each of a plurality of positions on the closed surface A plurality of reproduction audio signals corresponding to each of the plurality of positions generated by performing arithmetic processing on the audio signal based on the plurality of positions so as to have a geometrically equivalent positional relationship with the plurality of positions. Reproduction audio output means for outputting from each of the first speakers,
A dry output unit that outputs the audio signal from the second speakers arranged for the plurality of first speakers so as to have the same positional relationship as the sound generation position with respect to the closed curved surface without performing the arithmetic processing. Audio output means;
An audio signal processing device comprising:

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