WO1997038553A1

WO1997038553A1 - Acoustic system

Info

Publication number: WO1997038553A1
Application number: PCT/JP1996/000939
Authority: WO
Inventors: Hitoshi Ishiwata
Original assignee: City Promotion Network Co., Ltd.
Priority date: 1996-04-05
Filing date: 1996-04-05
Publication date: 1997-10-16
Also published as: EP0848572A1

Abstract

A microphone having a substantially spherical structure (1). A first microphone element (2a) is provided at the left end portion of the structure (1) and has a directivity in at least two directions; and a second microphone element (2b) is provided at the right end portion of the structure (1) and has a directivity in at least two directions.

Description

Specification

, System, stem

Technical field

The present invention relates to a microphone device for collecting a sound from which a reproduced sound rich in a three-dimensional effect and a sense of reality can be obtained, a method for processing a pop sound, and a recording medium on which the sound processed by the device and the method is recorded. About the broadcasting method.冃 Keigi i'w

In recent years, from the aspect of virtual reality, there has been a growing demand for more realistic sound reproduction. Conventionally, a stereo method has been proposed as a technique for obtaining realistic sound reproduction.

In this stereo system, the sound source is collected by a microphone L and a microphone R as shown in FIG. Then, the sound of the microphone R and the sound of the microphone R are respectively transmitted by the independent transmission system and the transmission system R, and are reproduced from the speaker R and the speaker R, respectively. As a technology other than the stereo method, a quadrature nick method has been proposed as a technique for obtaining a realistic sound reproduction.

FIG. 12 is a diagram for explaining the quadratic method.

As shown in Fig. 12, the recording method of the quadrature nick system is a microphone FZF! Located at the front right of the sound source. , Forward left The microphone FZ located at the rear is picked up from four microphones, the microphone RZR located at the rear right and the microphone RZL located at the rear left, to collect four channels.

Then, the sounds recorded by the four microphones are transmitted independently by the four transmission channels, respectively, and are reproduced from the four speakers geometrically arranged with the four microphones. It can provide a very realistic sound field.

However, in the above-mentioned stereo system, the sound field is not accurately localized, and there is a limit in reproducing a sound field full of a sense of reality.

In addition, the above quadraphonic method is based on the premise that four channels are collected and four channels are reproduced, but the localization of the sound field is limited.

Furthermore, if the four-channel sound collected by the quadratic method described above is combined into two channels and reproduced by two speakers, that is, in a stereo method, the reproduced sound has no more realistic feeling.

Therefore, the conventional stereo system or quadraphonic system could not reproduce realistic sound.

Furthermore, the current broadcasting system is generally stereo broadcasting, and there has been no branching technique that can provide realistic sound reproduction even when broadcasting using this stereoscopic broadcasting.

Then, an object of the present invention is to solve the above-mentioned problems. It is another object of the present invention to provide a microphone device capable of localizing a sound field to obtain a realistically reproduced sound, and a method and system for processing collected sound.

It is another object of the present invention to provide a recording medium and a broadcast method capable of localizing a sound field to obtain a realistically reproduced sound. Disclosure of the invention

An object of the present invention is to provide a substantially spherical structure, a first microfin element disposed at a left end of the structure and having directivity in at least two directions, and a right end of the structure. And a second microphone element having directivity in at least two directions.

The substantially spherical shape in the present invention is not limited to a spherical shape in a mathematical sense, but also includes a shape that can be virtually regarded as a sphere, and other shapes close to an ellipsoid. The substantially spherical structure preferably has a diameter of 10 to 5 Ocm. More preferably, the diameter is 10 to 40 cm, still more preferably, the diameter is〗 0 to 30 cm, and most preferably, the diameter is 15 to 20 cm.

In other words, if the approximately spherical structure is about the same as or slightly larger than the microphone element to which it is attached, the distance between each microphone element becomes short, which makes it difficult to obtain a rarely rich reproduction sound. . Conversely, if the substantially spherical structure becomes too large, the distance between each microphone element becomes large, and each microphone element can pick up sound from the same sound source as one. hard.

Further, it is preferable that the substantially spherical structure is made of a material having fine pores. In other words, the substantially spherical structure may have a solid structure.However, a structure made of a material having fine pores such as porous ceramics such as pumice or a foamed resin material is more preferable. A playback sound rich in three-dimensional effect was obtained.

In addition, a substantially spherical structure is provided in a substantially spherical skin, and inside the skin. It is even better if the composite structure has a sound absorbing material inserted therein. Further, it is preferable that the first microphone element and the second microphone element are stereo microphone elements.

If the microphone element is detachable by providing an arrangement part for disposing the microphone element on the above-mentioned substantially spherical structure, it is convenient when moving.

An object of the present invention is to provide a two-channel type first microphone element having directivity in at least two directions at a left end of a substantially spherical structure, and having directivity in at least two directions at a right end. Using a microphone device provided with a second microphone element of a two-channel type, the front channel of the first microphone element is connected to the first channel and the rear channel of the first microphone element. The channel is the second channel, the front channel of the second microchannel element is the third channel, and the rear channel of the second microchannel element is the fourth channel. A step of providing sound and an output means corresponding to each channel, and a step of reproducing the sound collected by four channels on four channels.

The sound reproduction method is characterized by having the following.

In other words, it is preferable that the microphone device reproduces the sound on four channels, and if the sound is reproduced in the same place as the place where the sound was collected, the sound is three-dimensional enough to give an illusion of being at the sound collecting place. Can be played.

An object of the present invention is to provide a two-channel type first microphone element having directivity in at least two directions at a left end of a substantially spherical structure, and having directivity in at least two directions at a right end. Having 2 channels Using a microphone device provided with a second microphone element of the type, the front channel of the first microphone element is used as the first channel, and the rear channel of the first microphone element is used. A second channel, a front channel of the second microphone element as a third channel, a rear channel of the second microphone element as a fourth channel, and sound collecting on four channels. Performing a predetermined frequency correction on the signal of the second channel and the signal of the fourth channel;

Synthesizing the second channel signal and the frequency-corrected second channel signal;

Synthesizing the signal of the third channel and the signal of the fourth channel whose frequency has been acquired;

V o achieved by the method of processing collected sounds characterized by having

The step of performing the frequency correction includes the second channel (the channel located at the rear left) and the fourth channel (the channel located at the rear right) of the four-channel sound signals collected by the microphone device. It is preferable to correct the frequency so that when the signal is plotted with the sound pressure plotted on the vertical axis and the frequency plotted on the horizontal axis, undulation occurs in the high frequency range. This can be considered as follows. The important thing in the characteristics of human hearing is the judgment of the sound before and after.However, even though the ears are located on the left and right sides of the head, it is possible to judge the positional relationship between the front and rear, because By change. The sound from the front is guided to the external auditory meatus by the complicated structure of the pinna, while the sound from the rear is a shield of the pinna, which seems to have a unique swell at high frequencies. For this reason, as shown in Fig. 4, a large drop of about 9 dB from 5 ◦ 0 to 110 Hz and a valley of about 2 dB With a peak of about 3 dB and attenuated from 400 Hz to 16000 Hz to the sound signals of the second and fourth channels. By performing the above-described correction, a reproduced sound full of a sense of standing can be obtained. It should be noted that the frequency correction is not limited to the frequency characteristics shown in FIG.

Further, it is preferable that the substantially spherical structure has a diameter of 10 to 50 cm.

The object of the present invention is to provide a two-channel type first microphone element having directivity in at least two directions at a left end of a substantially spherical structure, and having directivity in at least two directions at a right end. Using a microphone device provided with a second microphone element of a two-channel type, the front channel of the first microphone element is set to the first channel, and the rear channel of the first microphone element is set. A channel of the second microphone element, a front channel of the second microphone element as a third channel, and a rear channel of the second microphone element as a fourth channel, and collecting sound in four channels. Performing a predetermined frequency correction on the signal of the second channel and the signal of the fourth channel;

A first synthesizing step of synthesizing the signal of the first channel and the frequency-corrected signal of the second channel;

A second synthesizing step of synthesizing the third channel signal and the frequency-corrected fourth channel signal; A first difference signal generation step of subtracting the signal generated in the second synthesis step from the signal generated in the first synthesis step to generate a difference signal; A second difference signal generating step of subtracting the signal generated in the first synthesizing step from the signal thus generated to generate a difference signal; and a difference signal generated in the first difference signal generating step. A second delay step of delaying a predetermined time and generating a plurality of difference signals having different delay times from each other;

A second delaying step of sequentially delaying the difference signal generated in the second difference signal generation step for a predetermined time to generate a plurality of difference signals having different delay times from each other;

A third synthesis step of synthesizing the signal generated in the first synthesis step, the difference signal generated in the first difference signal generation step, and the plurality of difference signals generated in the first delay step When,

A fourth combining step of combining the signal generated in the second combining step, the difference signal generated in the second difference signal generating step, and the plurality of difference signals generated in the second delay step When

The method of processing collected sounds is characterized by having. This processing method is particularly suitable for the case where the sound collected by the microphone device is reproduced by a stereo-type (2-channel) reproducing device, that is, only two speakers.

The delay time of the delay step is preferably 0.5 to 1.0 msec. In particular, the delay step may be a step of generating two difference signals of 0.5 msec and 1.0 msec. preferable.

The third synthesizing step is a step of calculating a total volume of the difference signal generated in the first difference signal generating step and a plurality of difference signals generated in the first i! 5 process. The difference signal generated in the first difference signal generation step and the plurality of difference signals generated in the first delay step are adjusted so that the volume level does not become larger than the volume level of the signal generated in the first synthesis step. Combining the difference signals and the signal generated in the first combining step.

In the fourth synthesis step, the total volume of the difference signal generated in the second difference signal generation step and the plurality of difference signals generated in the second delay step is calculated. The difference signal generated in the second difference signal generation step, the plurality of difference signals generated in the second delay step, and the second synthesis step are controlled so as not to exceed the volume level of the generated signal. Preferably, it is a step of synthesizing the generated signals.

More preferably, when the volume level of the signal obtained in the first synthesis step is set to 1, the difference signal generated in the first difference signal generation step and a plurality of difference signals generated in the first delay step are obtained. If the total volume level of the signal and the signal are combined at 0.3 to 0.8 and the volume level of the signal generated in the second synthesis step is set to 1, the signal is generated in the second difference signal generation step. The sum of the generated difference signals and the plurality of difference signals generated in the second delay process is combined at a volume level of 0.3 to 0.8.

Particularly preferred is a ratio of about 0.6, ie a volume level ratio of the signal generated in the synthesis process to the difference signal and to a plurality of delayed difference signals is 1: 0.6.

Further, if the sound processed by the above-described processing method is recorded on a recording medium, a stereoscopic sound can be easily enjoyed by a stereo-type playback device. Furthermore, even if the sound processed by the above-described processing method is broadcast in a stereo system, the sound will be full of a three-dimensional effect and a sense of reality.

The object of the present invention is that the left front is the first channel and the left rear is the second channel. A channel conversion system that converts the sound collected from four channels into two channels, with the third channel on the right front and the fourth channel on the rear,

Frequency correction means for performing a predetermined frequency correction on the signal of the second channel and the signal of the fourth channel;

First synthesizing means for synthesizing the first channel signal and the frequency-corrected second channel signal;

Second synthesizing means for synthesizing the third channel signal and the frequency-corrected fourth channel signal;

In addition, the above-mentioned frequency correction means performs the sound pressure on the vertical axis and the frequency on the horizontal axis for the signal of the second channel and the signal of the fourth channel. It is preferable that the means be a means for correcting the frequency so that undulation occurs in a high frequency range when plotting is performed by using the following method.

In particular, the frequency correction means has a large drop of about 9 dB from 500 to 110 Hz and a peak of about 3 dB from 2000 to 300 Hz. It is preferable that the frequency characteristic is attenuated from 400 Hz to 160 Hz to the signals of the second channel and the fourth channel.

An object of the present invention is a sound signal processing system for processing a sound signal,

First difference signal generating means for subtracting the second channel signal from the first channel signal to generate a difference signal;

Subtract the first channel signal from the second channel signal and get the difference signal Second difference signal generating means for generating

A second delay means for sequentially delaying the difference signal generated by the first difference signal generation means for a predetermined time to generate a plurality of difference signals having different delay times from each other;

Second delay means for sequentially delaying the difference signal generated by the second difference signal generation means for a predetermined time, and generating a plurality of difference signals having different delay times from each other;

First combining means for combining the second channel signal, the difference signal generated by the first difference signal generating means, and a plurality of difference signals generated by the first delay means;

Second combining means for combining the second channel signal, the difference signal generated by the second difference signal generating means, and the plurality of difference signals generated by the second delay means;

This is achieved by a sound signal processing system characterized by having.

It is preferable that the delay time of the first and second delay means is 0.5 to 1.0 Omsec.

Further, the first synthesizing means is such that the total volume level of the difference signal generated by the first difference signal generating means and the plurality of difference signals generated by the first itt means is the first level. The difference signal generated by the first difference signal generation means, the plurality of difference signals generated by the first delay means, and the first channel signal are set so as not to become larger than the level of each channel signal. Configured to combine,

The second synthesizing unit is configured to set a sum of the difference signal generated by the second difference signal generating unit and the plurality of difference signals generated by the second delay unit to a second channel. Larger than signal volume level It is preferable that the difference signal generated by the second difference signal generation means, the plurality of difference signals generated by the second delay means, and the second channel signal be combined so as not to be lost. More preferably, when the volume level of the first channel signal is set to 1 in the first combining means, the difference signal generated by the first difference signal generating means and the first delay means are generated. And the sum of the volume levels of the plurality of difference signals is 0.3 to 0.8, and the second synthesizing means sets the volume level of the second channel signal to 1. In this case, the total volume level of the difference signal generated by the second difference signal generation means and the plurality of difference signals generated by the second delay means is combined in a range of 0.3 to 0.8. It is preferable to configure. Particularly preferred is 0.6. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a microphone device A according to the present invention,

FIG. 2 is a plan view of a microphone device A according to the present invention, and FIG. 3 is a block diagram of a channel conversion system.

Figure 4 is a frequency characteristic diagram.

FIG. 5 is a block diagram of the sound processing system 100,

Fig. 6 is a diagram for explaining the operation of the sound processing system 100, Fig. 7 is a diagram for explaining the operation of the sound processing system 100, and Fig. 8 is a microphone device for collecting four channels. This is a diagram for explaining the case where playback is performed on 4 channels.

Fig. 9 is a diagram for explaining the case where four channels of sound are collected by a microphone device, this sound is converted to two channels by a channel conversion system, and reproduced by a headphone. FIG. 10 is a diagram for explaining a case where sound is collected using a microphone device and this sound is processed by a channel conversion system and a sound processing system.

Fig. 11 is a diagram for explaining the conventional technology.

FIG. 12 is a diagram for explaining a conventional technique. BEST MODE FOR CARRYING OUT THE INVENTION

First, the microphone device of the present invention will be described. FIGS. 1 and 2 show a microphone device A according to the present invention. FIG. 1 is a perspective view, and FIG. 2 is a plan view.

In each figure, 1 is a sphere having a diameter of 18 cm. The inside of the sphere 1 is made of urethane foam resin, and the outside is made of FRP so as to surround the urethane foam resin. That is, the sphere 1 is composed of a skin FRP formed in the sphere and a urethane foam resin put in the inside thereof.

2a and 2b are stereotype microphone elements. As shown in the figure, the microphone elements 2a and 2b are arranged such that their bases are detachably embedded at both left and right ends of the sphere 1. As can be seen from FIG. 2, the microphone elements 2a and 2b are so arranged that the front left sound and the rear left sound can be picked up by the microphone element 2a. Thus, the sound on the front right and the sound on the rear right can be picked up.

Next, a description will be given of a channel conversion system that converts the sound collected from four channels into two channels using the above-described microphone device A.

FIG. 3 is a block diagram of the channel conversion system. The microphone Of the two channels (stereo) of the headphone element 2a, the channel that picks up the sound on the front left is the first channel FZL, and the channel that picks up the sound on the rear left is the second channel RZL. Of the two channels (stereo) of the microphone element 2b, the channel that picks up the right front sound is the third channel FZR, and the channel that picks up the right rear sound is the fourth channel RZR.

3 1 is an equalizer. The equalizer 31 receives the signal of the second channel RZL and the signal of the fourth channel R / R, and receives the signal of the second channel R / L and the signal of the fourth channel RZR. Are given the characteristics shown in Fig. 4 to perform frequency correction. That is, the sound of the second channel RZL and the sound of the fourth channel RZR have a large drop of about 9 dB at 500 to 110 Hz, and a valley of 2000 to 300,000. It is corrected so that it has a peak of about 3 dB toward 0 Hz and has a characteristic of attenuating from 400 Hz to 1600 Hz.

3 2 is a second synthesizer that synthesizes the sound of the second channel F / L and the corrected sound of the second channel R / L, and converts it into one channel.

3 3 is a second synthesizer that synthesizes the sound of the third channel FZR and the captured sound of the fourth channel RZR and converts it into one channel. Convert the result to two channels.

This channel conversion system is particularly effective when listening to headphones. Next, a description will be given of a sound processing system for processing a two-channel signal to reproduce a sound with a more three-dimensional effect.

FIG. 5 is a block diagram of the sound processing system 100.

5 1 is a first difference signal generation circuit. The difference signal generation circuit 51 is a circuit that subtracts the signal of the second channel from the signal of the first channel to generate a difference signal. That is, a matrix signal is generated.

52 is a second difference signal generation circuit. This difference signal generation circuit 52 is a circuit that subtracts the signal of the first channel from the signal of the second channel to generate a difference signal. That is, a matrix signal is generated.

5 3 to 5 3 _n are first delay circuits. Each delay circuit 5 3 ι ~ 5 3. , Different thigh times (0.5 msec to 1.0 msec) are set, and the output signal of the difference signal generation circuit 51 is delayed by the set delay time. For example, assuming that a delay time of 0.5 msec is set in the delay circuit 53, the output signal of the difference signal generating circuit〗 is output after being delayed by 0.5 msec in the delay circuit 53. You.

5 4 to 5 _4π are the second delay circuits. The delay circuits 5 4 ~ 5 4 _eta different times in (0. 5 msec~ 1. 0 msec ) is Bok set, delays the output signal of the differential signal generating circuit 5 2 only set Bok delay time. For example, assuming that a delay time of 0.5 msec is set in the delay circuit 54, the output signal of the difference signal generation circuit 52 is output after being delayed by 0.5 msec in the delay circuit 54. You.

55 is the first synthesizer. The synthesizer 55 includes a signal of the first channel, an output signal of the difference signal generation circuit 51, and delay circuits 53 to 53. The output signals of are synthesized. Note that the combiner 55 generates a difference signal generation circuit 51 when the volume level of the signal of the first channel is set to 1 at the time of synthesis. And the delay circuits 53 to 53 _n are combined so that the total level becomes 0.3 to 0.8.

Reference numeral 56 denotes a second synthesizer. This synthesizer 56 is a signal of the second channel, the output signal of the difference signal generation circuit 52; The output signals of are synthesized. Incidentally, when the synthesizer 5 6 synthesis, when the VOLUME level of the second channel signal is 1, the difference signal generating circuit 5 and second output signal and the delay circuit 5 4, the output signal of ~ 5 4 _n Combined so that the total volume is between 0.3 and 0.8.

Next, the operation of the system configured as described above will be described. Here, the delay circuits are referred to as a delay circuit 53, a delay circuit 53 ₂ , a delay circuit 54, and a delay circuit 54 _2, and are set to the delay circuit 53 and the delay circuit 54. 0. 5 msec delay time, the delay circuit 5 3 ₂ and the delay circuit 5 4 ₂ delay time set Bok 1. to 0 msec. The distribution ratio of the volume levels of the synthesizers 55, 56 is as follows. When the volume level of the channel signal is set to 1, the output signal of the difference signal generation circuit and the output signal of the delay circuit are output. The total volume level is ◦.

6 and 7 are diagrams for explaining the operation of the system. In the figure, 6 ◦ is a listener, 61 is a speaker arranged on the left side from the listener 60, and 62 is a speaker arranged on the right side from the listener 60. A signal output from the synthesizer 55 is generated from the speaker 61, and a signal output from the synthesizer 56 is reproduced from the speaker 62.

If the sound reproduced from the speaker 61 is all input to the left ear of the listener 60, and the sound reproduced from the speaker 62 is all input to the right ear of the listener 60, a sound with a very three-dimensional effect is obtained. Place. However, in reality, the sound reproduced from the speaker 61 is not only the left ear of the listener 60 but also a little delayed due to the influence of the human head, and is unnecessary sound for the right ear of the listener 60. Is entered. Similarly, the sound reproduced from the speaker 62 is input as unnecessary sound not only to the right ear of the listener 60 but also to the left ear of the listener 60 with a slight delay due to the influence of the human head. .

Therefore, in this system, the sound that cancels unnecessary sounds from the left and right speakers is superimposed on the originally required sound and output. This will be specifically described below.

From the speaker 61, a sound 61a (first channel signal) which is originally required and a sound 6〗 b (difference signal) which cancels unnecessary sound are output. Note that an unnecessary sound input to the right ear of the listener 60 is assumed to be 6〗 c.

The speaker 62 outputs an originally required sound 62a (second channel signal) and a sound 62b (difference signal) for canceling unnecessary sound. An unnecessary sound that is input to the left ear of the listener 60 is referred to as 62 c.

First, as shown in FIG. 6, let us consider a case where the listener 60 exists in the center of the speakers 61 and 62.

At this time, not only the sound 61a but also the sound 62c is input to the left ear of the listener 60. Therefore, the sound 62c is canceled by the delayed sound 61b (delay time 0.5 ms). Similarly, not only the sound 62a but also the sound 61c is input to the right ear of the listener 60. Therefore, the sound 61c is canceled by the delayed sound 62b (delay time 0.5 msec).

Next, as shown in FIG. 7, consider the case where the listener 60 is located near the speaker 60.

At this time, not only the sound 61a but also the sound 62c is input to the left ear of the listener 60. Therefore, the sound 6 1b (delay time 1.0 msec). Similarly, not only the sound 62a but also the sound 61c is input to the right ear of the listener 60. Therefore, the sound 61c is canceled by the sound 62b (the difference signal and the delay time is 0) which is not delayed.

It should be noted that the case where the listener 60 is present near the speaker 62 can be understood in the same way as in the above-described case.

Next, a description will be given of a result obtained by collecting sound using the above-described microphone device and processing the sound by a channel conversion system and a sound processing system.

First, a case in which four channels of sound are collected by the above-described microphone device and reproduced by four channels will be described.

FIG. 8 is a diagram for explaining a case where four channels of sound are collected by a microphone device and reproduced on four channels.

In room 81, microphone device A is placed in the center, a drum is placed on the front left, a piano is placed on the front right, a guitar is placed on the back left, and a bass is placed on the back right.

Next, in a room 82 similar to room 81, a speaker 83 is arranged on the front left, a speaker 84 is arranged on the front right, a speaker 85 is arranged on the rear left, and a speaker 86 is arranged on the rear right. Listeners were asked to listen.

Then, around the listener 87, a drum sound was heard from the front left, a piano sound was heard from the front right, a guitar sound was heard from the back left, and a bass sound was heard from the back right. As a result, it was found that when the sound collected using this microphone device was reproduced on four channels, the sound field was localized and a sound with a very three-dimensional effect could be reproduced.

Next, four-channel sound is collected by the microphone device described above, and this sound is converted to two channels by the channel conversion system, and the sound is converted by the headphones. The case of reproduction will be described.

FIG. 9 is a diagram for explaining a case in which four channels of sound are collected by the microphone device A, the sound is converted into two channels by the channel conversion system, and reproduced by the headphone.

Here, of the two channels (stereo) of the microphone element 2a, the channel that picks up the sound on the left front is the second channel FZ, and the channel that picks up the sound on the rear left is the second channel RZL. Of the two channels (stereo) of the microphone element 2b, the channel that picks up the right front sound is the third channel FZR, and the channel that picks up the right rear sound is the fourth channel RZR. Then, as shown in FIG. 9, the microphone device A was set at the center of the drum, piano, guitar, and bass, and sound collection was started.

Among the sounds collected via the microphone device A, the sound of the second channel RZL and the sound of the fourth channel RZR are input to the equalizer 31.

The equalizer 31 gives the sound shown in FIG. 4 to the sound of the second channel RZL and the sound of the fourth channel RZR to correct the frequency. The sound of the second channel RZL is synthesized by the synthesizer 32 with the first channel FZL. The sound of the fourth channel RZR is synthesized by the synthesizer 33 with the third channel FZR.

Then, I heard the sound converted from 4 channels to 2 channels on Headphones 91.

Then, a sound field full of immersiveness that was incomparable to the sound reproduced by the conventional stereo system was reproduced. That is, around the listener 92, a drum sound can be heard from the front left, a piano sound can be heard from the front right, and a rear sound can be heard. I heard a guitar sound from the left, and a bass sound from the rear right.

In other words, unlike listening with a headphone, unlike listening with a speaker, no unnecessary sound is generated, so it was found that a sound field with a sufficient three-dimensional effect can be reproduced only by performing frequency correction. .

Finally, a case where sound is collected using a microphone device and this sound is processed by a channel conversion system and a sound processing system will be described.

FIG. 10 is a diagram for explaining a case where sound is collected using a microphone device and the sound is processed by a channel conversion system and a sound processing system.

In this case, as described above, four channels of sound were collected by the microphone device A, and this sound was converted to two channels by the channel conversion system, and then further processed by the sound processing system 100. Here, the delay delay circuit circuit 5 3 ,, delay circuit 5 3 _2, the delay circuit 5 4, and a delay circuit 5 4 _2, the delay circuit 5 3, and the delay circuit 5 4, delay time set me the 0. 5 msec, the delay time set Bok to the delay circuit 5 3 ₂ ¾ beauty delay circuit 5 4 ₂ 1. 0 msec. The volume ratio of the synthesizers 55, 56 * The distribution ratio of the level is the volume of the channel signal. When the level is 1, the sum of the output signal of the difference signal generation circuit and the output signal of the delay circuit is given. Has a volume level of 0.6.

Then, reproduction was performed by the speaker 101 and the speaker 102. As a result, a sound field similar to that heard on the headphones was reproduced. That is, around the listener 103, a drum sound was heard from the front left, a piano sound was heard from the front right, a guitar sound was heard from the back left, and a bass sound was heard from the back left.

Considering the above results, this microphone device has four channels. The best results can be obtained when playing back with headphones, but if it is assumed that headphones will be used for listening, frequency correction and conversion to two channels can be done with less effort using the conventional stereo method. It was found that a sound field that could not be reproduced was reproduced.

It was also found that even with normal stereo playback (playback with two speakers), an excellent three-dimensional sound field was reproduced not only in front of the listener but also in the rear.

Furthermore, when the sound processed in the manner described above was recorded on a tape and played back, a sound field with a sense of reality that was not different from the above-described effect was reproduced.

In the above example, the collected sound was processed and then recorded on a 2-channel (2-track) tape recorder, but the collected sound was recorded once on a 4-channel (4-track) tape recorder. It may be processed later and recorded on a 2-channel (2-track) tape recorder.

Also, the recording medium is not limited to magnetic tape, but may be a record or CD.

Furthermore, when the sound processed as described above was broadcast on FM broadcast radio waves, a sound full of three-dimensionality and presence that could not be obtained by FM broadcast was flowing from a stereo type radio.

When broadcasting, not only FM broadcasting, but also stereo broadcasting (2-channel) broadcasting such as AM stereo broadcasting can reproduce a sound field full of presence.

Industrial applicability

As described above, according to the present invention, a sound full of a three-dimensional effect and a sense of realism can be obtained even in 2-channel or 4-channel reproduction. Therefore, it is a useful technology in the acoustic field.

Claims

The scope of the claims

1. A substantially spherical structure,

A first microphone element disposed at the left end of the structure and having directivity in at least two directions;

A second microfiber element disposed at the right end of the structure and having directivity in at least two directions;

A microphone device comprising:

2. The microphone device according to claim 1, wherein the substantially spherical structure has a diameter of about 0 to 50 cm.

3. The microphone device according to claim 1, wherein the substantially spherical structure is made of a material having fine pores.

4. The microphone according to claim 1, wherein the substantially spherical structure is a composite structure having a substantially spherical skin and a sound absorbing material placed inside the skin. apparatus.

5. The microphone device according to claim 1, wherein the first microphone element and the second microphone element are stereotype microphone elements.

6. A substantially spherical structure,

A first microphone element having directivity in at least two directions at left and right ends of the substantially spherical structure, and an arrangement section in which a second microphone element is arranged.

A microphone device comprising:

7. The microphone device according to claim 6, wherein the substantially spherical structure has a diameter of about 0 to 50 cm.

8. The microfiber device according to claim 6, wherein the substantially spherical structure is made of a material having fine pores.

9. The microfiber according to claim 6, wherein the substantially spherical structure is a composite structure having a substantially spherical skin and a sound absorbing material placed inside the skin. Equipment.

10. A two-channel type first microphone element having directivity in at least two directions at the left end of the substantially spherical structure, and having directivity in at least two directions at the right end 2 Using a microphone device provided with a second microphone element of a channel type, the front channel of the first microphone element is set to the first channel, and the rear channel of the first microphone element is set to the second channel. Channel, the front channel of the second microphone element is the third channel, the rear channel of the second microphone element is the fourth channel, and sound is collected by four channels; Providing output means corresponding to each channel, reproducing the sound collected on four channels on four channels, and

A sound reproducing method comprising:

11. The sound reproducing method according to claim 10, wherein the reproducing step is a step of reproducing the sound at a place similar to a place where the sound is collected.

1 2. At least two sides at the left end of the substantially spherical structure A microphone device comprising a two-channel type first microphone element having directivity in two directions, and a two-channel type second microphone element having directivity in at least two directions at the right end. The front channel of the first microphone element is the first channel, the rear channel of the first microphone element is the second channel, and the front channel of the second microphone element is the A third channel, a rear channel of the second microphone element as a fourth channel, and collecting sound on four channels; and a step of collecting the second channel signal and the fourth channel signal. Performing a predetermined frequency correction,

Synthesizing the third channel signal and the frequency-corrected fourth channel signal;

A method for processing collected sounds, the method comprising:

13. The method for processing collected sound according to claim 2, wherein the substantially spherical structure has a diameter of 10 to 50 cm.

1 4. The frequency correction process consists of plotting the sound pressure on the vertical axis and the frequency on the horizontal axis for the signal of the second channel and the signal of the fourth channel. 13. The method for processing a collected sound according to claim 12, wherein the step is a step of correcting the frequency so that undulations occur.

1 5. The frequency correction process involves a large drop of about 9 dB from 500 to 110 Hz, and a 200 to 300 Hz A correction that gives a frequency characteristic of about 3 dB to z and attenuates from 400 Hz to 1600 H2 to the signals of the second and fourth channels. 15. The method for processing a collected sound according to claim 14, wherein:

16. The first microphone element of the two-channel type having directivity in at least two directions at the left end of the substantially spherical structure, and the two-channel type having directivity in at least two directions at the end of the structure Using a microphone device provided with a second microphone element of a type, a front channel of the first microphone element is a first channel, and a rear channel of the first microphone element is a second channel. A step of collecting sound by four channels, wherein a front channel of the second micro-channel element is a third channel and a rear channel of the second micro-channel element is a fourth channel; Performing a predetermined frequency correction on the signal of the second channel and the signal of the fourth channel;

A second synthesizing step of synthesizing the signal of the first channel and the frequency-corrected signal of the second channel;

A second synthesizing step of synthesizing the third channel signal and the frequency-corrected fourth channel signal;

A first difference signal generation step of subtracting the signal generated in the second synthesis step from the signal generated in the first synthesis step to generate a difference signal; A second difference signal generating step of subtracting the signal generated in the first synthesizing step from the generated signal to generate a difference signal; and a difference signal generated in the first difference signal generating step. A first delay that delays a predetermined time and generates a plurality of difference signals having different delay times from each other. Rolling process,

A method for processing collected sounds, the method comprising:

1 7. The step of performing frequency correction is performed by plotting the sound pressure on the vertical axis and the frequency on the horizontal axis for the signal of the second channel and the signal of the fourth channel. 17. The method for processing a collected sound according to claim 16, wherein the step is a step of correcting the frequency so that undulation occurs.

1 8. The frequency correction process consists of a large drop of about 9 dB from 500 to 110 Hz, and a peak of about 3 dB from 200 to 300 Hz. Wherein the frequency characteristic is attenuated from 400 Hz to 160 00 H2 to the signals of the second channel and the fourth channel. Item 18. The method for processing collected sounds according to Item 17.

19. The method for processing collected sound according to claim 16, wherein the substantially spherical structure has a diameter of 10 to 50 cm.

20. The method for processing a collected sound according to claim 16, wherein the delay time is 0.5 to 1.0 msec.

21. The second delay step is a step of generating two difference signals having a delay time of 0.5 msec and a delay time of 1.0 msec, and the second delay step is a step of generating a delay time of 0.5 msec. 20. The method for processing a collected sound according to claim 20, wherein the method is a step of generating two difference signals having a delay time of 5 msec and a delay time of〗 msec.

2 2. In the third synthesis step, the volume level of the sum of the difference signal generated in the first difference signal generation step and the plurality of difference signals generated in the first delay step is the second level. The difference signal generated in the first difference signal generation step, the plurality of difference signals generated in the first delay step, and the This is a step of synthesizing the signal generated in the synthesizing step of 1,

In the fourth combining step, the sum of the difference signal generated in the second difference signal generating step and the plurality of difference signals generated in the second delay step is determined by the second combining step. The difference signal generated in the second difference signal generation step, the plurality of difference signals generated in the second delay step, and the second synthesis so as not to be greater than the volume level of the signal generated in the step. 17. The method for processing a collected sound according to claim 16, wherein the method is a step of synthesizing the signals generated in the step.

2 3. In the third synthesis step, when the signal level of the signal generated in the first synthesis step is set to 1, the difference signal generated in the first difference signal generation step and the first delay This is a process in which the total volume level of a plurality of difference signals generated in the process is 0.3 to 0.8. In the fourth synthesis step, when the volume * level of the signal generated in the second synthesis step is set to 1, the difference signal generated in the second difference signal generation step and the difference signal generated in the second delay step are generated. 22. The process of claim 22, wherein the total sound level of the plurality of difference signals obtained is a step of synthesizing at a level of 0.3 to 0.8. Method.

24. A recording medium characterized by recording a sound processed by the microphone device or the sound processing method according to any one of claims 1 to 23. .

25. A broadcasting method characterized by broadcasting sound processed by the microphone device or the sound processing method according to any one of claims 1 to 23.

2 6. Channel that converts the sound collected from 4 channels to 2 channels, with the left front as the second channel, the left rear as the second channel, the front as the third channel, and the right rear as the fourth channel. With the conversion,

A second combining unit that combines the signal of the first channel and the signal of the second channel whose frequency has been corrected,

A channel conversion system comprising:

27. The frequency correction means swells in the high frequency range when the sound pressure is plotted on the vertical axis and the frequency is plotted on the horizontal axis for the signal of the second channel and the signal of the fourth channel. Frequency correction so that 27. The channel conversion system according to claim 26, wherein the channel conversion system is a means.

2 8. The frequency correction means has a large drop of about 9 dB from 500 to 110 Hz, and about 3 dB from 2000 to 300 Hz. The second channel and the fourth channel are provided with frequency characteristics that are attenuated from 400 Hz to 16000 Hz. 28. The channel conversion system according to claim 27, wherein:

2 9. A sound signal processing system for processing a sound signal, comprising: first difference signal generating means for subtracting a second channel signal from a first channel signal to generate a difference signal;

Second difference signal generating means for subtracting the second channel signal from the second channel signal to generate a difference signal;

First delay means for sequentially delaying the difference signal generated by the first difference signal generation means for a predetermined time, and generating a plurality of difference signals having different delay times from each other;

First combining means for combining the first channel signal, the difference signal generated by the first difference signal generating means, and a plurality of difference signals generated by the first delay means,

Second combining means for combining the second channel signal, the difference signal generated by the second difference signal generating means and the plurality of difference signals generated by the second delay means; A sound signal processing system characterized by having.

30. The sound signal processing system according to claim 29, wherein the delay time of the first and second delay means is 0.5 to 1.0 msec.

3 1. The first synthesizing means sets the first volume level of the difference signal generated by the first difference signal generating means and the plurality of difference signals generated by the first delay means to a first level. The difference signal generated by the first difference signal generation means, the plurality of difference signals generated by the first delay means, and the first channel signal are set so as not to be larger than the channel level of the channel signal. It is configured to combine

The second synthesizing unit is configured to calculate a total volume level of the difference signal generated by the second difference signal generating unit and the plurality of difference signals generated by the second delay unit, as a second channel signal. The difference signal generated by the second difference signal generation means, the plurality of difference signals generated by the second delay means, and the second channel signal are combined so as not to be larger than the volume level. The sound signal processing system according to claim 29, wherein the sound signal processing system is configured as follows.

3 2. The first synthesizing means, when the level of the first channel signal is set to 1, is ^^ by the fifth signal means and the difference signal generated by the first difference signal generating means. The sum of the plurality of difference signals and the total volume level is configured to be 0.3 to 0.8. The second synthesizing means sets the volume level of the second channel signal. In the case of 1, the volume level of the sum of the difference signal generated by the second difference signal generation means and the plurality of difference signals generated by the second delay means is set. 31. The sound signal processing system according to claim 31, wherein the sound signal is configured to be synthesized in a range of 0.3 to 0.8.