JPS6035879B2 - Multi-channel stereo system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-channel stereo system, which allows the listener to hear substantially the same sound as the sound actually heard directly from the sound source with both eyes in the original sound field, even if the listener is in various directions during playback. The purpose of this invention is to provide a stereo system that allows you to listen to sound images, localization, etc.) through headphones.

Conventionally, as shown in Figure 1, a pseudo head (
A left ear signal LS and a right ear signal RS are generated by microphones 2 and 3 built-in and fixed to the positions of both ears of the dummy head) 1, respectively.
This binaural signal Ls,
There is a system in which the RS is outputted to headphones 6 of a listener 7 via amplifiers 4 and 5, respectively.

According to this method, the listener 7 can hear the same sound as when he or she is in the position of the pseudo head 1 in the original sound field, and as long as the listener stands still and listens, he or she can obtain a natural sound image, localization, and sense of presence. However, when listening to a real sound source, if the head is fixed, it is often difficult to judge the direction of the source, but when listening with this method, the same problem occurs when listener 7 holds the head fixed. If it is fixed, it has the disadvantage that it is difficult to accurately determine the direction of the sound source.

Further, since the listener 7 listens through the headphones 6, when the listener 7 moves his or her head, the sound image follows the head and moves, making it impossible to obtain a natural sound image and sense of presence. The present invention eliminates the above-mentioned drawbacks, and each embodiment thereof will be described with reference to FIG. 2 and the following figures.

In general, when listening to a sound source, if you keep your head fixed, it will be difficult to judge the direction of the sound source, as mentioned above, but as a way to eliminate this problem, you can rotate your head horizontally to listen to the sound source. Judging the position of is an extremely common practice in daily life. In other words, when the listener turns his or her head to the right, if the sound image moves to the left relative to the listener's head,
It can be determined that the sound source is in front, and if the sound image moves to the right with respect to the recipient's head, it can be determined that the sound source is in the rear. The system of the present invention focuses on the above-mentioned fact, and is configured so that the listener listening to the sound using headphones can determine the direction of the sound source by moving his or her head. b) A natural sound image can be obtained by eliminating the unnaturalness caused by the noise, that is, it is possible to hear substantially the same sound through the headphones as the sound that is actually heard from the sound source directly with both ears in the original sound field. This is what I did.

Figure 2 shows the first multi-channel stereo system according to the present invention.
A system diagram of an example is shown.

Now, as shown in FIG. 3, when the listener 7 is listening to the sound source 8 installed in the original sound field while facing in the direction 45o to the right with respect to the front (direction of arrow a), the sound source 8 is placed in the original sound field. left ear 10
G and L are the transfer characteristics from the sound source 8 to the right ear 10, G and R are the transfer characteristics from the sound source 8 to the right ear 10, and M is the signal supplied to the left ear 9 of the listener 7. The signals M and R supplied to the right ear 10' and the sound source 8 placed in the original sound field to the listener 7 as shown in FIG.
When listener is listening in the same position as in FIG. 3, facing left 45 o direction with respect to the front (direction of arrow a), the transfer characteristic from the sound source 8 to the left ear 9 of the listener 7 is G, and the sound source 8 is Let G2R be the transmission characteristic from 1 to the right ear 10, M station be the signal supplied to the left ear 9 of the listener 7, and M station be the signal supplied to the right ear 101. Here, as shown in FIG. 2, the signal extracted from the microphone 11 installed very close to the sound source 8 has the above-mentioned transfer characteristics G, L, G, R, G2L, G2R.
are supplied to circuits 12 to 15 having respective transmission characteristics, and signals M, MIR, and MIR are supplied to terminals 16 to 19, respectively.
They are taken out as M2L and M2R.

Note that the circuits 12 to 15 are constructed by appropriately combining a delay device, a phase shifter, a filter, and the like. In this case, if you listen to the signals taken out to terminals 16 and 17 with headphones (not shown), you can hear exactly the same sound as in the situation shown in Figure 3, and in the same way, the signals taken out to terminals 18 and 19 can be heard. If you listen to the signal with headphones (not shown), you can hear exactly the same sound as in the state shown in FIG. terminal 1
The signals M, R, and M stations taken out at stations 7 and 19 are connected to level control circuits 20 and 21, which are configured by variable resistors in a conversion circuit 56, respectively, and are increased or decreased according to the gain described later. The amount is increased or decreased as appropriate and supplied to the adder 24.

Similarly, signals M are output to terminals 16 and 18, respectively.
.
5. The signals extracted from adders 24 and 25 are supplied to headphones 26. Here, the sliders of the level control circuits 20 to 23 are configured to slide in conjunction with the movement of the listener's head, thereby providing level control. The gains in the direction of the listener's head in the level control circuits 20 and 22 are set as shown in line 1 in FIG. 5, and the gains in the level control circuits 21 and 23 in the direction of the listener's head are set as shown in FIG. It is set like straight line 0. FIG. 6 shows a schematic front view of one embodiment of a method for super-moving the sliders of the level control circuits 20 to 23 in accordance with the direction of rotation of the listener's 7 head.

In the figure, shafts 2 and 7 are fixed to the center of the headphones 26, and a universal joint 28 is fixed to the tip thereof. 29 is a spline shaft, one end of which is fixed to the universal joint 28, and the other end fixed to the universal joint 30'.

Reference numeral 31 denotes a shaft, and the above-mentioned bell compte is stored in a storage box 33 fixed to the ceiling 32.

The circuits 20 to 23 are connected to each other. Therefore, when the listener 7 faces a certain direction, the shaft 27 rotates accordingly.
This rotation is transmitted to the universal joint 28, the spline shaft 29, the universal joint 30, and the ball 31, and as the shaft 31 rotates, the level control circuit 20
~30 Numa movers are configured to work together. Therefore, according to the above configuration, when the listener 7 turns to the right direction 45o, the gains of the bell control circuits 20 and 22 become maximum, and the gain of the level control circuits 21 and 2 becomes maximum.
3 becomes the minimum, and listener 7's left ear 9 and right ear 1
The signals M, L and M, R are supplied as they are to the listener 7 in the original sound field as shown in Figure 3.
Substantially the same signal is supplied to the left ear 9 and the right ear 10' when the ear is turned to the right 45o direction.

Similarly, when the listener 7 turns to the left 45o direction, the gain of the bell control circuits 21 and 23 becomes maximum,
Moreover, the gains of the level control circuits 20 and 22 are minimized, and M2L is applied to the left ear 9 and right ear 10 of the listener 7, respectively.
and M2R are supplied as they are, and are substantially the same as the signals supplied to the left ear 9 and right ear 1 when the listener 7 turns to the left 45o direction in the original sound field as shown in FIG. The same signal is supplied. Also, when the listener 7 faces forward, the gains of the bell control circuits 20 to 23 are between the maximum and minimum, and the left ear 9 and the right ear 10' of the listener 7 are (re) and enjoyment (M・R+M
A signal is supplied to the left ear 9 and the right ear 10 when the listener 7 faces forward (in the direction of arrow a) in the original sound field as shown in FIG. 3 or 4. Substantially identical signals are provided.

Furthermore, even if the listener 7 faces in a direction within the range of 00 to 450 to the left or right from the front (direction of arrow a), the same direction as in the case of facing the front is reflected in the original sound field. Approximately equal signals are supplied to both ears when the earphones are connected. Therefore, when the listener 7 moves his head, the sound image moves left and right with respect to the listener's head, so the listener can easily judge the direction of the sound source. h) The unnatural sound of moving along with the head is eliminated, and a natural sound image and sense of presence can be obtained.

FIG. 7 shows the second multi-channel stereo system according to the present invention.
A system diagram of an example is shown.

In the figure, the same components as those in FIG. 2 are given the same reference numbers, and the explanation thereof will be omitted. In the figure, signals M, L, M, and R outputted to terminals 16 and 17, respectively, are supplied to level control circuits 34 and 36 in a conversion circuit 57, where they are appropriately increased or decreased according to the gain described later. Increased or decreased. terminal 1
The signals M2R and M2R outputted at 8 and 19, respectively, are supplied to level control circuits 35 and 37 in the conversion circuit 57, where they are appropriately attenuated by an amount of attenuation corresponding to the gain, which will be described later. Level control circuits 34, 35 and 36, 37
These signals are supplied to headphones 401 via adders 38 and 39, respectively. Here, the sliders of the level control circuits 34 to 37 are configured to move and slide according to the movement of the listener's head by using a device as shown in FIG. ，
The gain for the direction of the listener's head in 35 is 8th, respectively.
The gain in the direction of the listener's head in the level control circuits 36 and 37 is set as shown by the broken lines V and M in FIG. B, respectively. Here, for example, if the listener turns to the left in the 135o direction, the signals supplied to the right and left ears will be the same as when the listener turns to the right, if the ear shell 4 (auricle) is ignored. Since the signals supplied to the left and right ears can be considered to be substantially the same, as is clear from FIGS. If the user is supplied with a signal of 1350 degrees to the left, the setting is such that signals M, L and M, R are supplied to the right ear and left ear, respectively, when the user turns to the left 1350 direction. Therefore, according to the above-mentioned configuration, the level control circuits 34 to 37 can be controlled in accordance with the direction in which the listener faces within the range of oo to 360 degrees from the front in the same machine as that described in the first embodiment.
The gain of is varied to provide a signal that is substantially the same as that provided when in the original sound field.

Figure 9 shows the third example of the multi-channel stereo system according to the present invention.
A system diagram of an example is shown. In this figure, the same components as in FIGS. 2 and 7 are designated by the same reference numerals, and their explanations will be omitted.
Now, in FIG. 3 or 4, when the listener 7 tilts his head 900 degrees to the right or left while facing the direction shown in the figure, the distance from the sound source 8 to the upper ear of the listener 7 is The transfer characteristic is N, the signal supplied to the upper ear of the listener 7 is N, and the transfer characteristic from the sound source 8 to the lower ear of the listener 7 is N2. Let N2 be the signal supplied to the ear. Here, in the same manner as in the first embodiment or the second embodiment, the signal extracted from the microphone 11 installed very close to the sound source 8 is transmitted through a circuit having the above-mentioned transfer characteristic . 83, 84 and transfer characteristic G,
Circuits 12-1 having L, G, R, G2L, G2R
5 and are converted according to their respective transfer characteristics.

The signals taken out from the transfer characteristic circuits 12-15 are supplied to a conversion circuit 56 or 57, increased or decreased according to the horizontal head movement of the listener, and further supplied to level control circuits 85-88. On the other hand, the transfer characteristic circuit 83,
The signal taken out from 84 is the bell control circuit 8
9-92. Here, the sliders of the level control circuits 85 to 92 are configured to slide in conjunction with each other according to the inclination of the listener's head, and the gain in the level control circuits 85 and 88 is adjusted according to the inclination of the listener's head. is set as indicated by the broken line W in FIG. The gain is set as indicated by the broken line x in the figure, and the gain for the head tilt in the level control circuits 90 and 91 is set as indicated by the broken line X in the figure. The signals taken out from the level control circuits 85 to 92 are supplied to an adder 93 and further supplied to headphones 95. The sliders of the level control circuits 85 to 92 are arranged horizontally so as to slide according to the displacement angle of the universal joint 28 shown in FIG. 6, and detect the inclination of the listener's head.

Therefore, according to the above configuration, when a listener rotates his or her head horizontally or tilts his or her head to the left or right, the level control circuits 85 to 92 and the conversion circuit 56 or 57 adjust according to the movement of the head. The amount of increase or decrease in the level control circuit changes, and a signal corresponding to the movement of the head is supplied to the headphones.

Therefore, a more natural sound image can be obtained than in the case of only the first embodiment or the second embodiment. FIG. 11 shows the first or second embodiment of the multi-channel stereo system according to the present invention, and the
505 (Showa issue dated September 4) shows a system diagram of an embodiment that is a rough combination of one embodiment of the multi-channel stereo system proposed in No. 505 (Showa issue, September 4). In the figure, Samurai Isoaki 50 is shown surrounded by a dashed line.
- In the multi-channel stereo system circuit 45 proposed in No. 106505, the signals M・L, M・R, M2L, and M2 respectively input to the terminals 46 to 49 are supplied to the conversion circuit 50, and the transfer characteristics will be described later. is converted by the conversion circuit 5.
Signals SP, SP2 are applied to the output terminals 5 1 to 5 4 of 0, respectively.
, SP3, and SP4. Signal SP,,S
P2, SP3, and SP4 are supplied to speakers 41 to 44 installed at the four corners of the square, respectively, and signals are supplied from the speakers 41 to 44 to the listener located in the center. At this time, as shown in FIG. 12, when the listener 7 is facing the right direction 45o (direction of the speaker 43) with respect to the front (arrow a direction), the signal supplied to the left ear 9 of the listener 7 E,L
, the signals supplied to the right ear of the listener 7 are E, R, and the transmission characteristics from each speaker to the left ear 9 and right ear 10 are b, .
, b2, b, 3, b4, Q, , b42, b43, A4, the signals E, L and E, R become as follows.

Further, as shown in FIG. 13, when the listener 7 is facing left 450 (direction of the speaker 41) with respect to the front (direction of arrow a), the signal Esa supplied to the left ear 9 of the listener 7 is , the signal supplied to the right ear of listener 7 is the E bulb, and the transmission characteristics from each speaker to the left ear 9 and right ear 10 are b2,,Q2.
, b23, b24, wide, wide 2, wide 3, wide 4,
The signals E2L and E2R are as follows.

Therefore, if we combine the equations 0} and 2} into one, the signal E
．． However, L, E2L, E2R, E・R are as follows.

Therefore, the conversion circuit 50 is configured so that its output signal SP·, SP2
, SP3, and SP4, where B1 is an inverse matrix of B, the signals E, L, and E
2, E2R, E, R are as follows by substituting formula {4) into Ori-shiki,
However, B. E-1 becomes an identity matrix.

Therefore, in the reproduction sound field where the speakers 41 to 44 are arranged, when the listener 7 faces the direction shown in FIG. 12 or 13, the signals supplied to both ears are as shown in FIG. 3 or 4. This signal is substantially the same as the signal supplied to both ears of the listener 7 in the original sound field shown in the figure. On the other hand, the signal SP. taken out to the terminals 51 to 54 of the conversion circuit 50. ~S
P4 is supplied to the conversion circuit 55, and the signals M, L, M, R
, M2L, M2R.

Signals M, L, M, R, M taken out from the conversion circuit 55
The signal M2R is supplied to the conversion circuit 56 shown in FIG. 2 or the conversion circuit 57 shown in FIG. The signal is converted into a signal and supplied to the headphones 58. FIG. 14 shows one embodiment of a concrete circuit of the conversion circuit 55.

The signal conversion method in this conversion circuit 55 regards each of the four speakers 41 to 44 as one sound source, and converts the signals SP and -SP4 applied to each of the speakers 41 to 44 into a signal that was installed very close to the source in the past. Assuming that the signal is taken out from a microphone, we combine four sets of circuits corresponding to transfer characteristic circuits 12 to 15 in Figure 2 for the four signals for speakers to form a signal E, and then E2L, E2R, E, and R. It's something you get. In the figure, 59 to 74 are b, . The circuits 75 to 78 are adders having the characteristics .about.b44. Signals SP3 and S are applied to terminals 51 to 54 of the circuit configured as shown in the figure, respectively.
P. , SP2, SP4, the output terminals 79-8
2, signals E, L, E, E2R, E, and R are taken out. Note that the signals E, taken out to the output terminals 79 to 82,
L, E2L, E2R, E, and R are M2 and can be regarded as M2R, M, and R, respectively, according to the above formula [51]. Therefore, according to the above-described configuration, the signals SP, ~SP4 can be listened to through the speakers 41 ~ 44 or through the headphones 58 by playing back the disc or the like on which the signals SP, ~SP4 are recorded using the stereo device. , moreover, the signal supplied to both ears when a listener in the reproduction sound field faces a certain direction is substantially the same signal as the signal supplied to both ears when facing in that direction in the original sound field. becomes. Note that if the signals applied to the terminals 51 to 54 in FIG. In the reproduction sound field where the listener is placed, the listener can hear the same sound as the sound that is supplied to both ears when facing in that direction.

Similarly, if you input a monaural speaker signal, a 2-channel stereo speaker signal, or a multi-channel speaker signal and convert it into the 4-channel headphone signal of the present invention, you can hear the same sound as when listening through speakers. You can listen.

In this case, the conversion circuit has two sets of transfer characteristic circuits 12 to 15 in FIG. 2 when inputting a monaural signal, and two sets of circuits corresponding to transfer characteristic circuits 12 to 15 in FIG. 2 when inputting a 2-channel stereo signal. Furthermore, if multi-channel signals are input, circuits corresponding to the transfer characteristic circuits 12 to 15 in FIG. 2 are combined as many as the number of input channels. , FIG. 15 shows the first embodiment or the second embodiment of the multi-channel stereo system according to the present invention and the above-mentioned Showa 5th King 9.
A system diagram of another embodiment is shown, which is a rough combination of one embodiment of the multi-channel stereo system proposed on May 4th.

In the same figure, the same components as in FIG. 11 are given the same reference numerals.
The explanation will be omitted. In this embodiment, as is clear from FIG.
. Others are 11th
Since it is similar to the embodiment shown in the figure, its explanation will be omitted. Further, in FIG. 15, the description of the transfer characteristic circuit connected before the terminals 46 to 49 is also omitted. In addition,
In the above embodiment, the case where it is applied to 4 channels and 6 channels has been explained, but it can be similarly applied to other multi-channels. In order to correctly reproduce the original sound field signal to both ears, 2N channels may be used.

In addition, in the first and second embodiments described above, the case where the listener faced the 45 o direction to the right and the 45 o direction to the left was explained, but in the case of 4-channel stereo, no matter which two directions the listener plays, the original sound It is possible to obtain a signal approximately equal to the field. Furthermore, in the above embodiment, the case where the signal of one sound source is reproduced has been explained, but when dealing with a large number of sound sources, the conversion circuit 5 of FIG. 2 is used for each sound source.
6 is provided (in this case, transfer characteristic circuits 12 to 12) are provided.
The transfer characteristics of each circuit corresponding to 15 are appropriately set according to the position of each sound source), and the signals from each transfer characteristic circuit may be mixed and then supplied to the conversion circuit 56.

Furthermore, in a method that can faithfully reproduce the sound when the listener faces 45 o left and right, even when the listener faces in the front direction, almost the same signal as when facing the front in the original sound field is supplied, so the original sound can be reproduced faithfully. The number of channels does not necessarily have to be an even number in order to obtain a signal substantially equal to the signal in the field.

In addition to the mechanical device shown in Figure 6, another method for detecting the head movement of the listener is to place a light source at a predetermined position in the playback sound field, and direct the direction of the light from the light source to the headphones. A method of detection using a fixed photodetector, or
There is a method in which a device that generates magnetic lines of force in a specific direction is placed in the playback sound field, and the direction of the lines of magnetic force is detected using a magnetic field detection device fixed to the headphones. A method of detecting a rotation angle, etc. may also be used.

As mentioned above, the multi-channel stereo system according to the present invention is essentially based on the blue signal that reaches each listener's ears from the source when the listener faces different directions relative to the sound source in the original sound field. A plurality of transfer characteristic circuits with fixed characteristics obtain multiple electrical signals equivalent to , and detect the movement of the listener's head from the reference direction in the playback sound field to obtain an electrical signal corresponding to the amount of movement. a detection means; a level control circuit for increasing or decreasing the respective signals from the transmission characteristic circuit according to the output signal of the detection means; and a level control circuit that mixes the signals from the level control circuit for each channel and outputs the signals to the listener's headphones. By adjusting the level control circuit in a required manner, the signals from the plurality of transfer characteristic circuits are mixed at a predetermined ratio for each channel, so that the listener can hear the original sound during playback. Since the configuration allows the listener to hear substantially the same sound through the headphones as when listening directly to the sound from the sound source with both ears in the field, even if the listener faces various directions during playback, the sound in the original sound field remains the same. You can hear a sound that is almost the same as the sound that is supplied to both ears when you are facing the same direction. Therefore, when the listener moves his or her head, the sound image moves from side to side with respect to the listener's head, so the position of the sound source is affected. can be easily determined, therefore,
This eliminates the unnatural sound image that sticks to your head when you move your head, which was the case in the past, and allows you to obtain a natural sound image, localization, and sense of presence. By increasing or decreasing the gain according to the movement of the listener and supplying the headphones to the headphones, the listener can hear the same sound that is supplied to both ears when the listener is facing the same direction in the playback field where the speakers are placed. Similarly, it is possible to obtain a natural sound image, localization, and sense of presence, and there is no need for complicated compensation such as adjusting the delay time of a transfer characteristic circuit composed of delay devices and filters, and it is possible to obtain a natural sound image, localization, and presence. Since the configuration is such that the signals from the characteristic circuits are mixed at a predetermined ratio and supplied to the listener's headphones, the configuration for adjusting the characteristics is extremely simple, and this allows the delay and frequency characteristics to be adjusted, although indirectly. It has features such as sufficient compensation and adjustment, and therefore an extremely simple overall configuration.

[Brief explanation of drawings]

Figure 1 is a system diagram of an example of a conventional binaural system.
The figure is a system diagram of the first embodiment of the multi-channel stereo system according to the present invention, Figures 3 and 4 are diagrams for explaining the principle of the system of the present invention, and Figure 5 is the attenuation shown in Figure 2. FIG. 6 is a schematic front view for explaining the method of detecting head movement in the method of the present invention, and FIG. 7 is a system diagram of the second embodiment of the multi-channel stereo method according to the present invention. , FIG. 8 is a gain characteristic diagram of the attenuator shown in FIG. 7, FIG. 9 is a system diagram of the third embodiment of the multi-channel stereo system according to the present invention, and FIG. 10 is a diagram of the attenuator shown in FIG. Gain characteristic diagram,
FIG. 11 shows an embodiment in which the first or second embodiment of the system of the present invention is combined with an embodiment of the multi-channel stereo system previously proposed by the applicant in Japanese Patent Application No. 1065/1983. An example system diagram, Figures 12 and 13 are diagrams for explaining the principle of the multi-channel stereo system shown in Figure 11, and Figure 14 is an example of a specific circuit of the conversion circuit shown in Figure 11. The circuit diagram of FIG. 15 is the first or second circuit diagram of the method of the present invention.
FIG. 2 is a system diagram of another embodiment that combines the embodiment and one embodiment of the multi-channel stereo system previously proposed by the present applicant. 7...listener, 8...sound source, 9...
... Left ear, 10 ... Right ear, 11 ... Microphone, 12 - 15, 83, 84 ... Transfer characteristic circuit, 16 - 16, 46 - 49, 51 - 54...
・Terminal, 20-23, 34-37, 85-92...
...Attenuator, 24, 25, 38, 39, 93, 94・
...Adder, 26, 40, 58, 95...Headphone, 41-44...Speaker, 45...Multi-channel stereo system circuit proposed earlier by the applicant,
50, 55, 56, 57... Conversion circuit. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 15 Figure 14

Claims (1)

[Claims] 1. Specific fixation for obtaining a plurality of electrical signals that are substantially equivalent to the sound signals that reach the listener's ears from the sound source when the listener faces different directions relative to the sound source in the original sound field. a plurality of transfer characteristic circuits, a detecting means for detecting the movement of the listener's head from the reference direction in the reproduced sound field and obtaining an electric signal corresponding to the amount of movement; The level control circuit comprises a level control circuit that increases or decreases the signal according to the output signal of the detection means, and a means for mixing the signals from the level control circuit for each channel and supplying the mixture to the listener's headphone. By adjusting the circuits in a desired manner, the signals from the plurality of transfer characteristic circuits are mixed at a predetermined ratio for each channel, so that the listener can actually hear the sound from the sound source directly in the original sound field during playback. A multi-channel stereo system characterized by being configured so that substantially the same sound as heard with both ears can be heard through headphones.