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DESCRIPTION JPS53138301
Description or title of the invention
Generation method of 4-channel stereophonic sound signal
The two-channel stereophonic sound recording / reproduction method has been put to practical
use, in which two-channel stereophonic sound reproduction is performed using two reproduction
sound sources (speakers) arranged at predetermined intervals. EndPage: 20 years after 20 years
already! Also, it has been a long time since the so-called CD-4 system 4 channel stereophonic
sound recording and reproduction system developed by the applicant company and other 4
channel stereophonic sound reproduction systems were put into practical use Is well known as
σ), but a standard for the arrangement of four speakers has not yet been established with regard
to three-dimensional sound reproduction of four channels, and the program source for which
program creators are making is the object of production The fact is that program sources are
being produced on the assumption that speakers are placed in such a way that their intended 4channel reproduction effect can be best exhibited in relation to the type and content of the
program. Each of FIGS. 1 (a) to 1 (el) is representative of an arrangement of four loudspeaker
arrangements to 84 conventionally attempted in various 4-channel stereophonic sound
reproduction systems. It is explanatory drawing which illustrated sidetones of things, Comprising:
The code ¦ symbol M in each figure shows a listener. 1 (a) and 4 ('b) show the arrangement of the
speakers arranged in front of the listener M in four speakers S.about.84 (generally abbreviated as
4-.smallcircle. 1 (e) and 4 (d) show that two speakers S are arranged in front of the listener M
and the side of the listener y or the side of the listener y It is a speaker arrangement (generally
abbreviated as 2, 2 FT) of the form where two speakers 63I 84 are arranged in front of the side
(Fig. 1 111 (Fig. 1111 shows two each in front and back of listener M) The speaker arrangement
(generally abbreviated as 2-2SD) of the type in which the speakers Blr 82 * 83 s 84 are arranged
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is shown. By the way, conventionally, in various 4-channel stereophonic sound systems, a signal
'f: used for 2 channel stereophonic sound reproduction is given to a 2-channel stereophonic
sound reproduction device to thereby perform 2-channel stereophonic sound reproduction. Also,
consideration is often given to the signal form so that it can be used at the time of 2-channel
stereophonic sound reproduction without any loss of information content contained in 4-channel
stereophonic signals. A signal in the form of the sum of two sets of two predetermined twochannel signals in the four-channel stereophonic sound signal is provided by the two-channel
stereophonic sound reproducing apparatus.
An example thereof is to be used for two-channel stereophonic sound reproduction. Even if twochannel stereophonic sound reproduction is performed by the two-channel stereophonic sound
reproduction device without causing any loss of information content in the four-channel
stereophonic sound signal as described above, the two-channel stereograms The mode of
localization of the sound image obtained by sound reproduction is completely different from that
intended by the producer of the program source for 4-channel stereophonic sound reproduction
in preparation for the program source, and it has been said conventionally The four channel
stereophonic sound-compatible with the two-channel stereophonic sound reproduction that has
just come to such an expression, focusing only on the point that there is no loss in the signal
content. However, with regard to the aspect of the localization of the sound image etc., there is
no compatibility except in special cases. The following is a specific example of this point. That is,
for example, FIG. 1 (FIG. 1) shows an example of the arrangement of four speakers used for
producing a 4-channel channel stereo sound by the producer of the 4-channel channel stereo
sound reproduction program source. d) With the 2-2FT speaker arrangement as illustrated in
mind, the listener M in the 4-channel stereophonic sound reproduction moves from the left side
to the front left side and the front right side to the right side In the case where a 4-channel
stereophonic sound signal is configured to receive a sound image and this 4-channel
stereophonic sound signal is provided to a 2-channel stereophonic sound reproduction
apparatus, the 4-channel stereophonic sound signal is A signal in the form of the sum of the left
side channel signal and the left front channel signal 'is supplied to the left front speaker in the
two-channel stereophonic sound reproducing apparatus. A signal in the form of the sum of the
right front channel signal and the right side channel signal in the 4-channel stereophonic sound
signal is supplied to the right front speaker in the 2-channel stereophonic sound reproducing
apparatus to reproduce the 2-channel stereophonic sound. EndPage: The movement of the sound
image perceived by the listener who is reproducing the program source for four-channel
stereophonic sound reproduction described above by means of EndPage: 32 channel
stereophonic sound is stopped for a while at the position of the left front speaker. The sound
image was moving at position 1 on the right front of the speaker and stopped there for a while.
This is completely different from the sound image movement mode as described above intended
by the creator of the program source.
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As described above, the four-channel stereophonic signal that is conventionally considered to be
compatible with two-channel stereophonic sound reproduction lacks the compatibility regarding
sound image localization, and this point is a four-channel stereophonic program source. In
addition to being a major cause of difficulties in the production of program sources for the
creators of this project, there is also one problem in the implementation of 4-channel
stereophonic sound broadcasting that is being planned recently. It is being discussed. The
present invention is a sound image localization in a method based on the recognition mechanism
of sound image localization of human beings, that is, basically the condition when the listener is
listening to the sound from the real sound source according to the concept of pinaural. Solves the
above-mentioned problems by generating a 4-channel stereo acoustic signal that can be given to
the both ears of a listener who is performing 2-channel stereo sound reproduction by a 2channel stereo sound reproduction device using a 2-channel stereo sound reproduction device.
Hereinafter, the contents will be specifically described with reference to the attached drawings.
First, a recipient who has a normal hearing hears the direction of a sound source (real sound
source) that is present at a specific position (direction) in space, the difference in the signal level
of the sound signal (both-ears signal) given to both ears Sound pressure difference) or phase
difference (time difference), which is given to the left and right ears of the listener by sound
waves emitted from a plurality of reproduction sound sources (speakers) The signal level
difference and the phase difference (time difference) in the acoustic signal are the signals in the
acoustic signal respectively given to the left and right ears of the listener by the sound wave
emitted from the real sound source present at a specific position in space. In the case where the
level difference and the phase difference (time difference) are exactly the same, the listener who
is listening to the sound waves emitted from the plurality of reproduction sound sources is
present at a specific position in the above-mentioned space. It emits from the real sound source
to The sound level is localized at any spatial position other than the reproduced sound source
actually emitting the sound wave, if the signal level difference and the time difference in the
binaural signal are appropriately set since it can be perceived as being With regard to the
localization of a sound image, it is possible to use a signal having no localization information as
an original signal, and from the original signal, a plurality of signals 1ki having different signal
levels and phases, according to K When driving a plurality of speakers arranged in a space, a
binaural signal given to the listener is the same as a binaural signal to be obtained as an output
signal using a pinaural signal generator when a sound source is assumed to be present. Image
localization method (Japanese Patent Application Laid-Open No. 50-43002) in which a plurality
of the above-mentioned plurality of signals are made so as to obtain a stable signal Japanese
Patent Application Sho .DELTA.l-20098), the signal conversion Soryou (Japanese Patent
Application No. Sho 51-21313), many other proposals have been made.
Then, these sound image localization devices use signals having no localization information (for
example, so-called monaural signals, certain h are individual channel signals in multi-channel
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stereophonic sound signals, etc.) as input signals for busy, and When the outgoing signal from it
is respectively supplied to a plurality of speakers arranged in a predetermined arrangement
manner in space, the sound waves emitted from the plurality of speakers are generated in the
listener's both ears The listener feels the localization of the sound image as in the case where the
sound source corresponding to the input signal is actually present at a specific position (or
direction) in the space intended to localize the sound image by the acoustic signal. Sound signal
localization configured as being capable of outputting the above-mentioned output signal having
signal content that can be As long as it has the function as described above, any configuration
may be used depending on the configuration. However, Japanese Patent Application No. 15120098 proposed by the applicant company as this sound image localization apparatus, It is
advantageous to use a device to which a technique such as Japanese Patent Application No. 51EndPage: 42 or 3L3 is applied, since the sound image localization apparatus can be configured
with a simple configuration. FIG. 2 is a block diagram of an example of the configuration of the
sound signal localization apparatus S-O proposed in Japanese Patent Application No. 51-20098
related to the application of the applicant company, and in FIG. It is an input terminal of the
signal which does not have information (a monaural signal or individual channel signal of multi
channel stereophonic sound signal), and the signal which does not have localization information
in the input terminal 1 to the block as an input signal When added. If the sound source day
corresponding to the input signal is present at a specific position in the space intended to localize
the sound image, then a pinaural signal generator (for example, the position of the left ear and
the right ear of the artificial head) Using the structure of individually attached microphones), it is
possible to obtain as output signals Ls and Rs from the pinaural signal Le similar to the pinaural
signal to be obtained as the output signal, Rsft output terminal 2 lightning 3 The first signal
conversion device configured as described above, SX, (a second signal to which the pinaural
signal Ls, 'BJa output from the first signal conversion device described above is applied to the
input terminal 4.5 The second signal conversion device EIX2 is a conversion device, and the
output terminals Lep and Rsp output from the output terminals 6 and 7 are empty so as to form
a reproduction sound field. When supplied to a plurality of speakers 8.9 (the case where two
speakers are used in FIG. 2 'is illustrated in FIG. 2) disposed in the interior, the listener M may
hear through the space from the speakers. Sound signal (Binaural signal) XAgRe given to both
ears of the audio signal is in the form of a signal such that crosstalk to be generated in the
reproduction sound field has been canceled in advance so as to become the above-mentioned
pinaural signal Signal conversion characteristics.
Next, the above-described signal conversion characteristics to be included in the first signal
conversion device α □ and the second signal conversion device α2 described above will be
described. FIG. 3 shows the transfer characteristic Ehx between the sound source B and the
listener M when the sound source S is present in the direction of the left front θ degree of the
listener M, assuming that the angle M is the front of the listener M. 8f and the listener M's
binaural signals Lel and Re ', and the listener M's binaural signal Shi Re' in the case of FIG. , Sn, it
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is expressed as the following α) equation. (] = S · [,] ... (1) Re 'The output signal fLs of the first
signal conversion device 5XXL. Assuming that Rs, this output signal u, Rs is identical to the
listener M [provided with binaural signals Le 'and Re' based on the actual sound source S as
shown in FIG. 3 described above, ie, (Ib) In the case of (-), the following equation (2) is
established, and the signal conversion characteristic of the first signal conversion circuit SX,
which can produce such an output signal, is 1, while the second Output signal 1 bp of the signal
conversion device α 2 of In order for the binaural signal Le, Re to be supplied to the listener MK
to be supplied to the speaker 8.9 when Rsp is the same as the output signal 'Ls, R8 from the first
signal conversion device SX □ described above, It is necessary that the output signals Lap and
Rsp in a state in which crosstalk to be generated in the reproduction sound field configured using
the speakers 8 and 9 is canceled in advance are individually provided to the speakers 8.9iC. Now,
the output signal Ti3p from the second signal converter. The transmission characteristics
between the left ear and the right ear of the listener M in the playback sound field formed by the
speakers 8 and 9 supplied with Rsp and the speakers 9 and 8 are respectively the left of the
listener M through the speaker 8 With the ear 1 ... a through the speaker 9 with the right ear 1 of
the listener M ... through the speaker 8 with the right ear 1 of the listener M ... b through the
speaker 9 with the left ear 1 of the listener M Assuming that the transmission characteristic A of
the reproduction sound field described above is expressed as A = (a) (3) above (3), both of the
transmission characteristics are given to the listener M. The ear signals Le and Re and the output
signal Tpp of the second signal conversion device BX2 supplied to the speakers 8 and 9. There is
the following relationship with Rsp. (R,) = A (尊) ··· (4) However, binaural signals Le and Re 4 f
equal to the output signals LEI and Rs to the first signal conversion device, and the listener M in
the reproduction sound field In order to give both ears, the output signal J1, ep, Rsp from the
second signal EndPage: 5 converter needs to be made as shown by the following equation (5).
cLsp) == T, Al (ゝ) (5) 5pRfl (where T is a delay) Thus, the above sound image localization
apparatus intends an input signal not including localization information, Noinal signal r
representing a sound image localized in an arbitrary direction. A plurality of binaural signals 1e
and Re having the same signal form as the four signal signals Ls and Rs produced by the first
signal conversion device f3X1 for equal conversion and the first signal conversion device SX1
described above are plural This signal is given to the speaker by modifying the signal line Ls, RfIf
so as to cancel the crosstalk occurring in the reproduction sound field in advance so as to be
given to the listener in the reproduction sound field formed by using the speakers Since the
second signal conversion device SX2 for producing the signals Lsp and Rsp is connected in
cascade, each signal conversion device can be easily configured by a simple filter, a delay circuit,
a calo calculator, etc. Conversion can be performed at once through the entire frequency band
that is the target of signal conversion, so if the output signal to the fidelity signal conversion
device is given to headphones and listened with a simple configuration, PINO When you are Lal
reproducing b Migihitsuji advantage is the also obtained. And, as already stated, it is the first
signal conversion device, and in the example shown in the figure, the physical properties Sn, Sf
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between the real sound source S and the listener M's ears are referred to (see FIG. 3). . The
transfer characteristic 8 n represents the transfer characteristic between the sound source S and
the ear closer to the sound source S in the listener M, and the transfer characteristic S f is far
from the sound source S and the sound source S in the listener M Of the circuit 10 having the
same characteristics 8n'l as the transfer characteristic an) and the characteristics of the ratio of
the transfer characteristics 8n and Sf, that is, the difference physical property between the two
ears in It is constituted by the n circuit 11 provided. The circuit 10 described above is configured
by a filter as a circuit whose frequency response characteristic changes in accordance with θ to
be set, and the circuit 1m described above also has frequency response characteristics and
frequency versus time difference characteristics in accordance with θ to be set As a circuit
which changes in, it is comprised by combination of a filter and a delay circuit. The input signal
not having localization information supplied to the input terminal l passes through the circuit 10
having a 5 n Ivf property in the first signal conversion device 85, and the output terminal 2 heno
(one ear signal of the The output of the circuit lO described above is output as the left ear signal
L8 in the illustrated example, and the output of the circuit lO described above passes through the
circuit 11 having 4 characteristics n to the output terminal 3 / the inoural signal And the other
ear signal (shown as a right ear signal in the illustrated case).
The above two signals Rs output to the output terminal 23 of the above-described first signal
conversion device 8X are, for the existing sound source S, a pinaural signal obtained when using
a pinaural signal generator and It is the same, and if the headphone is connected to the terminal
2.3 and it listens, stereo reproduction by a pinaural signal can be performed. The output signals'
m, Rs from the first signal conversion device described above are applied to the input terminal
number 5 of the second signal conversion device EIX2. M2 signal converter 8x2Il'i, as already
described, its output terminals 6. When the output signals Lep and Rsp from '7 are respectively
supplied to the individual speakers to form a reproduced sound field, the binaural signals Le and
Re to be supplied to the listener M in the reproduced sound are the second mentioned above. An
output signal L8p of a signal form in which crosstalk generated in the reproduction sound field is
eliminated in advance so that input signals r and Rθ of the signal conversion device SX2 have
the same signal form as the input signal r and Rθ. A signal conversion device capable of
converting to Np, that is, has characteristics as indicated by T-A in the above-mentioned equation
(5). The following equation is obtained by rewriting equation (5) showing the relationship
between the input and output signals of the second signal conversion unit & SX2. EndPage: 6 The
second signal conversion device SX2 shown in the example shown in the figure is constructed by
specifically circuitizing the equations (5a) and (5b) described above, and 12a and 12b are
buffers. The amplifiers 13a and 14a and 131) and 141) are circuits configured to havecharacteristics by respective ones or by a filter and a delay circuit, 15a and 15b are inverters, 6
at 16 b Ia adders, 17 a and 1 l. '7tln each one by filter and delay circuit. Using the signal Is, Rs
applied to the input terminals 4, 5, the output signal Lsp of the required signal form. It is
converted to Rsp. The second signal conversion device 8x2 is not limited to the configuration as
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shown in the example shown in the drawing, and, for example, even if all the ones as shown in
Japanese Patent Application No. 50-'75209 are used. Good. The sound image localization
apparatus of the second illustration shown above has the output terminal 6. of the second signal
conversion device Sx2. If an output signal of 2-channel system is obtained from F, and the output
signal is given to a speaker arranged so that a 2-channel stereo sound field can be released, both
channels of listener M can be obtained by 2-channel system. It can give a signal. FIG. 4 is a fourchannel stereophonic sound signal of the present invention, and in this FIG. 4, 2ON 23 is each
channel signal LF, RF in the original four-channel stereophonic sound signal.
The input terminals of the IIB 9 RB, and the housings 24 to 27 are the output terminals of the
modified 4-channel signal 騙, R−1 □, R main, and are originals individually input to the abovedescribed input terminal buttons 昂Each channel signal of the four-channel stereophonic sound
signal, such as RF, IJB, and RB, is individually provided with sound image localization circuits 8IO
□, S02. S Engineering 03. It is individually applied to each input terminal 1'1'1021103I "04 in
S04. Each sound image localization circuit 8 described above may be configured according to the
construction principle described with reference to FIG. 2 described above, for example. The input
terminals 1 ° □ to 104 and the output terminals 6 ° 1 to 6 ° 7 ° □ 0 to 04 in each of the
sound image localization circuits 8 in 0 □ to S 4 in FIG. The suffixes 01 to 04 are added to input
terminals and output terminals corresponding to the input terminal l and the output terminal 6.7
at 0, and they are symbols represented so that the correspondence relationship becomes clear.
The signal gift 19% 1 individually output from the output terminal 6 ° P 2 O 3 in the above
sound image localization circuit S O O 11 town 02 is added by the adders ADD, P and output to
the output terminal U in the modified 4-channel stereo acoustic signal The signal 栴 + Rw, which
is output as the 禄 channel signal − and is individually output from the sound image localization
circuit EEIIO 95 I 02 K output terminal 701 + 702, is added by the adder ADD rf and is added to
the output terminal 26. It is output as an Rp channel signal RFh in a stereophonic sound signal.
In addition, the signals LB1 individually output from the output terminals 6 ° 3 and 6 4 in the
sound image localization circuit 8 and the steps 3 and 4 04, respectively. Bll is added by the
adder ADD1 or the like, and output to the output terminal 26 as a rice channel signal に お け る
in the modified four-channel stereophonic sound signal, and the signal localization circuit S. 03.
RBr individually output from the output terminal +7 CB ′ 704 in S 04 is added to the adder
node by 1 and output to the output terminal 27 as the RB channel signal I lb in the modified 4channel stereo acoustic signal . Thus, transmission of a known 4-channel signal to each channel
signal of the modified 4-channel stereo acoustic signal individually output from the output
terminals 24 to 27 to the 4-channel stereo acoustic signal transformer The signal is transmitted
or recorded / reproduced through a system or a recording / reproducing system, and used as a
signal for 4-channel stereophonic sound reproduction or used as a signal for 2-channel
stereophonic sound reproduction.
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In FIG. 4, modified four-channel stereophonic signals individually output from the output
terminals 24 to 21y of the four-channel stereophonic signal transforming device FX are divided
into two sets of sum signals -1 in the mad v-lux circuit MX. And the difference EndPage: 7 signals
Ldl−. And the sum of the above two sets! The difference signals have signal configurations as
shown in the following equations (6) to (9), respectively. -One employment eleven ... (6)% = "pa" R
扼 ... (-1) Multiple = 嘔-騙 ... (8) "a = Rya-R ca ..., (9) Two sets of sum / difference signals shown in
the above equations (6) to (9), ie, two sets of sum signals -9 and two sets of difference signals -9etc. Although transmission, recording and reproduction are performed by the system, R selfrecording reproduction system, an embodiment of the transmission, recording and reproduction
may be appropriately selected and used among known means. For example, when the above four
sum and difference signals are intended to be recorded and reproduced by the disk record, the
four sum and difference signals may be recorded while being compressed according to the socalled CD 鴫 method developed by the applicant company. Well, when transmitting by broadcast
waves, for example, it may be broadcasted according to a so-called 4-channel stereophonic sound
system known as the so-called Darren system. Note that the generated 4-channel stereophonic
sound signal is transmitted, In the case of recording and reproduction, the sum of signal
configurations as shown in the above-mentioned equations (6) to (9). It is not required to be
converted into a signal, that is to say, when a 4-channel stereophonic sound signal is reproduced
by a 2-channel stereophonic sound reproduction device, the signal supplied to the 2-channel
stereophonic sound reproduction device is It may be in the form of two sets of sum signals, for
example, each channel signal -t "BatRFa'R" in a modified four-channel stereophonic signal
adjacent track on a magnetic tape or other recording medium Even if it has been made to record
two sets of sum signals in the form of (IjFa "%) # (" z "'Bl) at the time of reproduction, it is
sufficient. In FIG. 4, a partial US shown in the right side of the figure shows that the two sum
signals -1Ra by the modified four-channel stereophonic signal obtained by the No. channel
stereophonic sound signal generation method of the present invention are two-channel
stereophonic playback device. When given as one input signal, what localization of sound image
can be given to a listener M who is at a predetermined place with respect to two speakers 8.9
and faces a predetermined direction? The sum signal 、, and the range of localization of the
sound image that can be given to the listener M by the sum signal 飄 will be described below.
In FIG. 4, a sum signal having a signal configuration like the equation (6) given to the input
terminal 18 in the two-channel stereophonic sound reproducing apparatus is amplified by the
amplifier Masuda and then supplied to the speaker 8. The sum signal 有 す る having a signal
configuration as shown in the equation (7) given to the input terminal 19 is supplied to the
speaker 9 after being amplified by the amplifier 29. The 4-channel stereo [9-channel equalchannel signal layer and the RF channel signal RFa output from the output terminal 4.25 in the
4-channel stereo-acoustic signal transformer FX are the original 4 channels supplied to the input
terminal 20. Equal channel signal layer of stereophonic sound signal and RF channel signal R,
etc., sound image localization circuit EI 工 0 □. １３Ｉ０２． The position of the sound image
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formed by the above-described signal%-% being supplied to the speakers 8 and 9 is the abovementioned sound-. According to the setting method of the signal conversion characteristic of the
image localization circuit B-O-B-B-O 02, a range of about 180'ji at the one-side near the one side
of the listener M to the one-side near the other side of the listener M It can be made at any
intended position within. In addition, one channel signal 楡 of the modified four-channel stereo
acoustic signal and the RB channel signal RBa output from the output terminal 26.2'7 in the fourchannel stereo acoustic signal transformer Fx are supplied to the input terminal 22.23.顯 channel
signal of the original 4-channel stereophonic sound signal and city channel signal RB are
modified by circuits such as sound signal localization circuits S-C03 and S-C04, and adders ˜ b,
Ar5rv and b, The position of the sound image formed by supplying the above-mentioned signal
− ′ ′ lh to the speaker 8.9 depends on the setting method of the signal conversion physical
property of the sound image localization circuit 5IO 3 ° 6 04 mentioned above, the listener M It
is possible to have an intended EndPage: 8 within the approximate range of about X8 in the
category of about 1 from just beside one side of the side to the just beside side of the other side
of the listener M. Therefore, in the case where the program source based on the original fourchannel three-dimensional audio signal is produced on the assumption of 4-0 format or 2-2FT
format as an arrangement of four speakers at the time of reproduction, By setting the signal
conversion characteristics of each sound image localization circuit in the 4-channel stereophonic
sound signal transformation apparatus FX, localization of the sound image as intended by the
creator of the program source as obtained by using four speakers is% 22 channel sound It can
also be perceived by the listener who uses the playback device, and a program source based on
the original four-channel stereophonic sound signal is produced on the assumption that the
arrangement of four speakers at the time of playback is the 2 + 28D format. Even if the fourchannel three-dimensional acoustic signal deformation device FX Aspect of sound image
localization by a program source produced assuming four loudspeakers of 2-2SD format by
setting of signal conversion characteristics of the image localization circuit Sound image by four
loudspeakers of 2-2FT format Sound localization as if the four signals were localized at each apex
angle of the area of the quadrangular shape arbitrarily set forward of the listener, as in the
localization mode of As a mode, the listener can be made to sense.
Thus, the 4-channel stereophonic sound signal obtained by the 4-channel stereophonic sound
signal generation method of the present invention is a signal in the form of the sum of two
predetermined two successive channel signals in it. With respect to the two speakers in the twochannel stereophonic sound reproducing apparatus when supplied as a two-channel signal to the
standing sound reproducer, to the listener pointing in a predetermined direction at a
predetermined position in the original four-channel stereophonic signal The sound images
corresponding to the respective channel signals can be heard as being localized at different
positions, and according to the non-invention method, all the problems described above are well
resolved. It should be noted that each channel signal of the four-channel stereophonic sound
signal generated by the method of the present invention is required in space by an arrangement
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mode adapted to four-channel stereophonic sound reproduction by the original channel
stereophonic sound signal. When four-channel stereophonic sound reproduction is performed by
supplying to four speakers arranged in the above, the localization of the sound signal
corresponding to each channel signal is slightly shifted from the position of each speaker. The
state of three-dimensional sound reproduction is not significantly deteriorated, and the
conventional four-channel three-dimensional sound reproduction apparatus can perform fourchannel three-dimensional sound reproduction without any difficulty. FIG. 5 shows that the
sound image corresponding to the signal of channel + Rp in the original 4-channel stereophonic
sound signal is localized at the positions of the two speakers 8 and 9 in the 2-channel
stereophonic sound reproducing apparatus. This is an example of a case where sound images
corresponding to the signals of the other two channel rice and RB in the original four-channel
stereophonic sound signal are localized outside the two speakers 8.9, respectively. FIG. 6 shows
that in the positions of the two speakers 8 and 9 in the two-channel stereophonic sound
reproducing apparatus, one channel in the four-channel stereophonic sound signal and signals
corresponding to the stationary channel are localized, respectively. The other two channels in the
four-channel stereophonic sound signal etc. = signal and the corresponding signal are between
the two speakers 8, 90 respectively In a position which is an example of a case that is adapted to
be localized, respectively. As described above, in the case where sound images corresponding to
specific channel signals are localized to the positions of the two VCs 3 and 8 at the time of 2channel stereophonic sound reproduction, the above-described in the 4-channel stereophonic
sound signal transformation circuit FX is performed. Each sound image localization circuit to be
provided corresponding to each specific individual channel signal is significantly simplified in its
configuration, and no adder is required, as shown in FIGS. 5 and 6. If it is 9, it is not good.
That is, in FIG. , The sound localization circuit S O □ given to the input terminal l. A very simple
configuration, in which the connection between the output terminal 6 ° and the output terminal
6 is made by a conductive EndPage: 9 line (the output terminal 7 ° is not connected to the
circuit and is in a non-signal state) The sound image localization circuit S 02 02 02 where the RF
channel signal R 2 is given to the input terminal 1 2 2 is also its input terminal l. (2) and the
output terminal 7 ° 2 are connected by a conductor only (output terminal MA. Circuits are not
connected to □ and no signal is provided), and the adders ADD,..., ADD, f are omitted. Similarly,
the sound image localization circuit S in FIG. As for the S 04, they have an extremely simple
configuration in which the input terminal 1 3 and the output terminal 603 are connected by a
conducting wire (in the case of the sound image localization circuit 8 9 03), and the input
terminal l . It has a very simple construction (in the case of the sound image localization circuit 8
or 04) in which only the connection between the terminal 4 and the output terminal +704 can be
made by a conductor (in the case of the sound image localization circuit 8), and the adders
M5D1ADD, ADD, わ are omitted. Further, in the above-described four-channel three-dimensional
sound signal deforming device Fx of the sixth illustration, the equal channel in the original fourchannel three-dimensional sound signal is realized by the circuit such as the sound image
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localization circuit S.sub.011S. Signal conversion is performed so that sound images respectively
corresponding to the signal portion and the channel signal RF are localized at different positions
between the two speakers 8 and 9 in the two-channel stereophonic sound reproducing
apparatus. However, as described above, as a sound localization circuit for localizing a sound
image between two speakers, a simple configuration in which only in-phase crosstalk is simply
provided is sufficiently practical. In the example shown in FIG. 7, the rice o ′ ′ B channel signal
in the original 4-channel stereo acoustic signal is moved to a position slightly outside the position
of the two speakers 8 and 9 in the 2-channel stereo sound reproducing apparatus. In the case
where the corresponding sound image is localized respectively, and the sound image
corresponding to the signal of the IIF of the original 4-channel stereo acoustic signal and the RF
channel is localized at different positions between the two speakers 8t9. Indicates In general,
when a sound image is produced by processing a virtual image outside the position of one
speaker, the more the difference between the position of the sound image and the position of the
speaker, the more the difference signal component. When the listener moves his head in the hall,
topological discomfort increases.
Therefore, in order to reduce such unpleasantness, each different sound image is localized at a
position slightly outside the position of the two speakers, and each position of the two speakers
is In the case where the sound images are localized, the distances between the positions at which
the four sound images are localized become unequal, so the sound images intended to move at a
constant speed are also unequal speeds. There is a problem that it is expressed as a moving
sound image. However, as in the example shown in FIG. 7, when the four signals corresponding
to each channel signal in the original four-channel stereophonic sound signal are localized, it is
apparent that the above-mentioned problems do not occur. In such a point, it is meaningful to
use the aspect of sound image localization shown in FIG. In addition, as a sound image
localization circuit for localizing the sound image to the position slightly outward of the speaker,
a simple configuration having a simple reverse phase crosstalk can be used. The sound image
localization circuit used in the practice of the present invention is, for example, one in which the
distance at the position 1 at which the sound image is localized is also variable as shown in, for
example, Japanese Patent Application No. 51-27313. It may be. In the description above, the
movement of the sound image in two-channel stereophonic sound reproduction by the twochannel stereophonic sound reproduction device is perceived as listener pressure as-→) → → →
RB, RB-+ RF → job →- In the case described above, if the movement of the message is to the
listener, the order is → 顯 → RB-+ RF, RF-+ RB-+ T. → You may set the constant of the sound
image localization circuit so that it will be in such a state, if you want it to feel like 坏. As is
apparent from the details described above, the four-channel stereophonic signal generation
method of the present invention is in the form of a signal of the sum of two sets of
predetermined two successive channel signals in a four-channel stereophonic signal. A listener
who faces a predetermined direction at a predetermined position as a four-channel stereophonic
signal EndPage: 10 to be used listens to the sound waves emitted from the two reproduction
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sound sources. A sound image localization circuit is provided for each channel signal in the
original four-channel stereophonic signal so that the sound image corresponding to each channel
signal in the original four-channel stereophonic signal can be heard as localized at different
positions. Because it is the one that has been subjected to signal modification and elimination, the
4-channel stereophonic sound signal according to 1 non-invention system is 2 channels. If the
signal supplied to the two-channel stereophonic sound reproduction device is in the form of a% 2
set of sum signals when being reproduced by the three-dimensional stereophonic sound
reproduction device, each channel signal in the original four-channel stereophonic sound signal
With respect to a listener who is facing a predetermined direction at a predetermined position
with respect to two speakers in a two-channel stereophonic sound reproducing apparatus, the
corresponding sound signals are respectively near one side of one side of the listener to near
another side of one side 1 Can be localized at any of the intended positions within the range of
about 18 leaves, and thus all the problems already described are well solved by the present
invention scheme.
In addition, even if each channel signal of the four-channel stereophonic sound signal generated
by the method of the present invention is supplied to four speakers arranged as required in the
space to perform four-channel stereophonic sound reproduction, it is impossible. It is possible to
perform no four-channel stereophonic sound reproduction, and it is possible to significantly
facilitate the creation of programming in the four-channel stereophonic sound system by
adopting the present invention system. １
Figure 1 also (Figure 説明 鴫 (は is an explanatory view of the arrangement of the re-main sound
source (speaker) in the four-channel stereophonic sound main system, Figure 2 is a block
diagram of an example of the sound image localization circuit FIG. 3 is an explanatory view of a
transfer characteristic between an existing sound source and a listener, and FIG. 4 to FIG. 7 are
block diagrams of the system of the present invention, respectively. S-O, B-O 01-8 IO 4 ... Sound
image localization circuit, F x -4 channel 3D sound signal transformation circuit% α □ · · I signal
conversion device, SX 2 · · Second signal conversion device, ADD, f, jl ,. D to bt, b, · Adder, B, 9. S
□ ˜ S4 ・ ・ Speaker, M · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · １１
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JPS5823491

JPS52124301

JPS5957089

JPS53135302

JP2015119248

JPS4952603

JPS5148001

Document 1001845

JPS49120202

JPS51134102