JP3397579B2 - Sound field control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound field control device for controlling a sound field using electroacoustic equipment.

[0002]

2. Description of the Related Art Conventionally, an apparatus for controlling a sound field using electro-acoustic equipment is described in, for example, Japanese Patent Laid-Open No. 3-168175. FIG. 4 shows the configuration of a conventional sound field control device. In FIG. 4, 401 is a sound field, the sound field has a sound source 403, and a listener 406. Reference numeral 402 is a microphone, 404 is a reverberation characteristic control device, and 405 is a speaker.

Next, the operation of the above conventional example will be described.
In the sound field 401, the sound emitted from the sound source 403 is input to the microphone 402. The output of the microphone 402 is input to the reverberation characteristic control device 404, and reverberation is electrically added. The output of the reverberation characteristic control device 404 is emitted from the speaker 405 in the sound field 401. To the listener 406 in the sound field 401, the reverberation sound from the speaker 405 arrives together with the sound from the sound source 403.

In this way, even in the conventional sound field control device, the sound field control can be performed and the characteristics of the sound field can be changed.

[0005]

However, in the above-mentioned conventional sound field control device, when the sound radiated from the speaker is input to the microphone, a feedback loop is generated, and the feedback energy from the speaker to the microphone becomes large. There is a problem in that howling occurs when the timbre of the reverberant sound deteriorates and the return energy increases.

It is an object of the present invention to provide a sound field control device capable of suppressing howling and deterioration of tone color in such a sound field control system.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a sound field control device including a reverberation sound adding device and a phase inverter.
The reverberation adding device is installed in the sound field.
Reverberation is generated by adding reverberation to the sound from the microphone
And at least one speaker installed in the sound field
Reverberant sound is output to the
Phase reversal of the reverberation sound generated by the adder device
Inverted phase to at least one speaker installed
A sound field controller for outputting the reverberation, the arbitrary shape
With respect to the sound field, there is an effect that the sound field control can be performed while suppressing the occurrence of howling and the deterioration of the tone color only by the phase inverter .

According to a second aspect of the present invention, the sound is
The field is symmetrical, and the sound pickup microphone is symmetrical to the sound field.
It is installed on the axis and reverberant sound whose phase is inverted from that of the reverberant sound
The output speaker is symmetrical with respect to the axis of symmetry of the sound field.
The sound field control device according to claim 1, wherein when the number of microphones is one, only one phase of the speaker is inverted to suppress howling and deterioration of tone color. It has an effect that field control can be performed.

According to a third aspect of the present invention, the sound
The field is bilaterally symmetric, and the reverberation adding device is
Instead of the sound from the microphone, multiple
Adds reverberation to the mixed sound from the pickup microphone
Generating a reverberant sound, the plurality of sound collecting microphones
Arranged symmetrically with respect to the nominal axis, reversing the phase of the reverberation
The speaker that outputs the reverberant sound is
The sound field control device according to claim 1, wherein the sound field control device is arranged symmetrically with respect to each other , and in the case of a plurality of microphones, only how to invert one phase of the speaker causes occurrence of howling and deterioration of tone color. It has the effect that the sound field can be controlled while being suppressed.

[0010]

The invention according to claim 4 of the present invention is the above-mentioned
Of claims 1 to 3 with a FIR filter connected to one or more of the speaker that outputs the reverberant sound obtained by inverting the phase
A sound field control apparatus according to any one, has the effect of an arbitrary shape of the sound field, it is possible to perform the sound field control while suppressing generation or tone of deterioration of the howling only FIR filter.

[0012]

[0013]

According to a seventh aspect of the present invention, as means for outputting the phases of reverberant sounds output from adjacent speakers so that they are different from each other, a speaker that directly outputs the output of the reverberant sound adding device and a phase 7. The sound field control device according to claim 6, wherein there are two types of speakers for inverting and outputting, and the two types are arranged without being spatially biased, and a natural effect is obtained in the entire sound field only by inverting the phase. be able to.

The embodiment of the present invention will be described below with reference to FIG.
3 to FIG. 3 will be described.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention. In FIG. 1, 101 is a sound field, and the sound field has a sound source 103 and listeners 109, 1
I have 10. 102 is a microphone, 104 is a reverberation sound adding device, and 105 is a delay device. Reference numeral 106 is a phase inverter, and 107 and 108 are speakers. 111
Is a sound path from the speaker 107 to the listener 110, and 112 is a sound path from the speaker 108 to the listener 109. Further, 113 is an acoustic path from the speaker 107 to the microphone 102, and 114 is an acoustic path from the speaker 108 to the microphone 102. The sound field 101
Are symmetric about axis of symmetry 115, and microphone 102 is above the axis of symmetry. In addition, the speaker 107 and the speaker 10
8 is symmetrical with respect to the axis of symmetry 115.

Next, the operation of the first embodiment will be described. In FIG. 1, a sound source 1 in a sound field 101
The sound emitted from 03 is input to the microphone 102, converted into an electric signal, and input to the reverberation sound adding device 104. The reverberation sound adding device 104 electrically adds the reverberation sound.
The device for adding the reverberation sound may be a device using a combination of well-known IIR filters or a device using an FIR filter. Also, a combination of an IIR filter and an FIR filter may be used. The output of the reverberation sound adding device 104 is input to the delay device 105 and gives an appropriate delay to the reverberation sound so as to satisfy the well-known preceding sound effect. Delay device 105
Is branched into two, one of which is amplified and then output from the speaker 108 as it is. The other is inverted in phase by the phase inverter 106 and then amplified and output from the speaker 107. The phase inverter 106 is a DSP
Although it can be realized by signal processing using, etc., it can be easily realized by a device in which the positive and negative of the signal line are simply connected in reverse. The reverberant sounds output from the speakers 107 and 108 reach nearby listeners 110 and 109 to realize the effect of sound field control. The reverberant sound output from the speaker 107 is
Although the phase of the reverberant sound output from the speaker 108 is opposite, the difference in the sense of hearing is slight. The signal output from the speaker 107 reaches the microphone 102 via the acoustic path 113, and the signal output from the speaker 108 reaches the microphone 102 via the acoustic path 114.
Since the sound field 101 is symmetrical about the axis of symmetry 115, and the speakers 107 and 108 are also symmetrical about the axis of symmetry 115, the respective speakers 107 and 108 are connected to the microphone 10.
Since the signals that have reached 2 cancel each other out when they are combined, the signals from the speakers 107 and 108 that are actually input to the microphone 102 are few, and the energy of the speakers is 1
Compared with the case of only one, it becomes 10 dB or less. In this way, since the energy output when the signal output from the speaker is input to the microphone is reduced, it is possible to perform sound field control while suppressing howling and deterioration of tone color.

In the present embodiment, the case where one microphone 102 is provided on the axis of symmetry 115 has been described. However, even when a plurality of microphones are arranged symmetrically with respect to the axis of symmetry, the outputs of the microphones are mixed. Then, the same effect can be obtained. Further, in the present embodiment, the case where there is one speaker 108 to which the output of the delay device 105 is directly connected and one speaker 107 to which the output of the delay device 105 is inverted and connected is explained, but each signal is further branched. Even if two or more speakers are connected to each other, the same effect can be obtained as long as the speakers are located symmetrically with respect to the axis of symmetry.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention. In FIG. 2, 201 is a sound field, and there is a sound source 202 in the sound field.
There is 212. Reference numeral 203 is a microphone, 204 is a reverberation sound adding device, and 205 is a delay device. 206 is FI
R filters, and 207 and 208 are phase converters. 209 and 210 are speakers. 213 is an acoustic path from the speaker 209 to the listener 211,
Reference numeral 214 is an acoustic path from the speaker 210 to the listener 212. Further, 215 is a speaker 209 to a microphone 20.
3, and 216 is an acoustic path from the speaker 210 to the microphone 203. The shape of the sound field 201 is arbitrary, and the microphone 203 and the speakers 209, 21
The position of 0 is also arbitrary.

The operation of the second embodiment will be described next. In FIG. 2, the sound source 2 in the sound field 201
The sound emitted from 02 is input to the microphone 203, converted into an electric signal, and input to the reverberation sound adding device 204. The reverberation sound adding device 204 electrically adds the reverberation sound.
The device for adding the reverberation sound may be a device using a combination of well-known IIR filters or a device using an FIR filter. Also, a combination of an IIR filter and an FIR filter may be used. The output of the reverberation adding device 204 is input to the delay unit 205, and gives an appropriate delay to the reverberation to satisfy the well-known preceding sound effect. Delay device 205
Is branched into two, one of which is amplified by the phase converter 208 and is then output from the speaker 210. The other is amplified through the FIR filter 206 and the phase converter 207 and then output from the speaker 209. The phase converters 207 and 208 are set so that the phases of their respective outputs deviate from each other by 180 °. FIR filter 2
Reference numeral 06 denotes the position of the microphone 203, and determines the coefficient so that the signal from the speaker 209 and the signal from the speaker 210 cancel each other. The simplest device for determining the coefficient is a device that corrects only the time difference between the acoustic path 216 from the speaker 210 to the microphone 203 and the acoustic path 215 from the speaker 209 to the microphone 203. As a more accurate coefficient determination device, there is a known inverse filter processing device that determines a coefficient at which the signal from the speaker 209 and the signal from the speaker 210 cancel each other at the position of the microphone 203. Speaker 209,
The reverberation sound output from 210 is the listener 211,
At 212, the sound field control effect is realized. The signal output from the speaker 209 reaches the microphone 203 via the acoustic path 215, and the signal output from the speaker 210 reaches the microphone 203 via the acoustic path 216. As described above, the signals arriving at the microphone 203 from the respective speakers 209 and 210 cancel each other when they are combined, so that it is possible to perform sound field control while suppressing howling and deterioration of timbre.

(Third Embodiment) FIG. 3 shows a third embodiment of the present invention. In FIG. 3, reference numeral 301 denotes a sound field, and a sound source 304 exists in the sound field and listeners 321 and 3
There are 22. Reference numerals 302 and 303 are microphones, 305 is a reverberation sound adding device, and 306 to 309 are delay devices. Reference numerals 310 to 312 denote phase inverters, and 313 to 31.
Reference numerals 8 and 319 are speakers. Note that the sound field 301 is symmetric with respect to the symmetry axis 320, and the microphones 302 and 30
3 is symmetrical with respect to the axis of symmetry 320, and the speakers 313 and 314, 315, 316, 317 and 318 are also symmetrical with respect to the axis of symmetry 320.

The operation of the third embodiment will be described next. In FIG. 3, the sound source 3 in the sound field 301
The sound emitted from 04 is input to the microphones 302 and 303, converted into an electric signal, and the two signals are mixed and input to the reverberation sound adding device 305. Reverberation device 305
Then, reverberant sound is added electrically. The device for adding the reverberation sound may be a device using a combination of well-known IIR filters or a device using an FIR filter.
Also, a combination of an IIR filter and an FIR filter may be used. The output of the reverberation sound adding device 305 is branched and input to the delay devices 306 to 309, and an appropriate delay is given to the reverberation sound so as to satisfy the known preceding sound effect. Delay device 306
The outputs from ˜308 are respectively branched into two, one of which is amplified through the phase converters 310 to 312 and then output from the speakers 313, 316, and 317. The other is amplified and then output from the speakers 314, 315, 318. By arranging a speaker that outputs reverberant sound whose phase is inverted and a speaker that does not reverse phase spatially, there is a natural sound field control for the entire sound field 301 while suppressing howling and deterioration of timbre. It can be performed. Further, the output of the delay device 309 is output from the speaker 319 after being amplified. In this way, by mixing the speakers 313 to 318 whose outputs cancel each other out and the same speaker 319 as the conventional one, the sound field near the axis of symmetry 320 can be made closer to the nature.

[0023]

As described above, according to the present invention, the sound pickup microphone, the reverberation sound adding device, and the plurality of speakers are provided, and the reverberation sounds are output from the plurality of speakers. Since the outputs are made to cancel each other out, it is possible to perform sound field control while suppressing howling and deterioration of tone color.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a sound field control device according to a first embodiment of the present invention.

FIG. 2 is a schematic block diagram of a sound field control device according to a second embodiment of the present invention.

FIG. 3 is a schematic block diagram of a sound field control device according to a third embodiment of the present invention.

FIG. 4 is a schematic block diagram of a conventional sound field control device.

[Explanation of symbols]

101 sound field 102 microphone 103 sound source 104 Reverberation sound addition device 105 delay device 106 phase inverter 107 speaker 108 speakers 109 listener 110 listeners 111 sound path 112 sound path 113 sound path 114 sound path 115 axis of symmetry 201 sound field 202 microphone 203 sound source 204 Reverberation device 205 delay device 206 FIR filter 207 Phase converter 208 Phase converter 209 speaker 210 speaker 211 listeners 212 listener 213 Sound path 214 sound path 215 sound path 216 Sound path 301 sound field 302 microphone 303 microphone 304 sound source 305 Reverberation sound addition device 306 delay device 307 delay device 308 delay device 309 delay device 310 Phase Inverter 311 Phase Inverter 312 Phase Inverter 313 speaker 314 speaker 315 speaker 316 speaker 317 speaker 318 speaker 319 speaker 320 symmetry axis 321 listener 322 listener

─────────────────────────────────────────────────── ───Continued from the front page (56) References JP 61-169898 (JP, A) JP 3-54995 (JP, A) JP 4-277997 (JP, A) JP 6- 149276 (JP, A) JP 6-284493 (JP, A) JP 5-181489 (JP, A) JP 9-247787 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G10K 15/00 G10K 15/12 H04R 3/12 H04S 1/00

Claims (4)

(57) [Claims] 1. A reverberation sound adding device and a phase inverter
A sound field control device, wherein the reverberation sound adding device is a sound field control device.
Reverberation by adding reverberation to the sound from the sound pickup microphone installed in
At least one that produces a sound and is placed in said sound field
The reverberant sound is output to the speaker of the
The reverberation sound generated by the reverberation sound addition device is phase-inverted and
Phase to at least one speaker installed in the recording field
A sound field control device that outputs a reverberant sound that is inverted . 2. The sound field is bilaterally symmetric,
Iku is installed on the axis of symmetry of the sound field, and
A speaker that outputs reverberant sound with inverted phases is
The sound field control device according to claim 1, wherein the sound field control device is arranged symmetrically with respect to an axis of symmetry . 3. The sound field is symmetrical and the reverberant sound
The additional device replaces the sound from the sound pickup microphone with the sound field.
Mixed from multiple pickup microphones installed inside
Reverberation is added to the sound to generate a reverberation sound, and
Iku is placed symmetrically with respect to the symmetry axis of the sound field,
A speaker that outputs reverberant sound with its phase inverted from the reverberant sound.
Is arranged symmetrically with respect to the axis of symmetry of the sound field.
The sound field control device according to claim 1. 4. A sound field control according to any one of claims 1 to 3 with a FIR filter connected to one or more of the scan <br/> peak mosquito for outputting a reverberation obtained by inverting the phase apparatus.