JPH06233394A - Surround signal processing unit - Google Patents

Abstract

PURPOSE:To obtain the surround signal processing unit from which a stereophonic effect similar to the surround reproduction system employing both one system of a surround use signal for a rear use and/or one system of a surround signal for a center use is obtained by using only a speaker arranged in front of a listener. CONSTITUTION:The processing unit is provided with a signal conversion circuit 13 converting a rear channel signal S into a space localizing signal to localize the signal at an intended position in space, one of the output Ls and an inverse signal of the other output Rs are fed to one of the channel signal L by adders 17, 19 and an output Rs and an inverse of output Ls are fed to other channel signal R by adders 18, 20. The respective signals are given to speakers SP1, SP2 arranged on the left and right sides in front of a listener M for the reproduction. Thus, rear speakers SP3, SP4 arranged substantially on the left and right sides in the rear of the listener are made useless to obtain a surround stereophonic effect. Similar processing is applied to a center channel signal C. When the sound image localization position is symmetrical to the left and right positions, number of filters consisted of the conversion circuit 13 is halved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound image localization apparatus for reproducing an acoustic signal by a speaker, and more particularly to a surround signal processing apparatus for surround reproduction surrounding a listener.

[0002]

2. Description of the Related Art Conventionally, in order to reproduce stereophonic sound capable of obtaining a sound field or sound image localization from the listener's position to the rear, two speakers in front of a stereo arrangement and a speaker in rear of a surround are arranged. Minimum of 1 or 2 in total 3
A speaker is required, and surround playback and high-definition 3-1 that use one surround signal
When reproducing up to the center channel as in the system, one or two speakers are further required as a center speaker, and an amplifier and a cable for the reproduced channel are required.

That is, the speaker settings required for surround reproduction are, for example, as shown in FIG. 8, L and R channel speaker sets located on the left and right in front of the listener M, and SL located on the left and right behind. And rear speaker set for SR channel surround,
Alternatively, in addition to this, a C-channel center speaker in the front center part was required.

However, in a general home, it is difficult to arrange the rear speaker and the center speaker in terms of space and cost. Therefore, as an actual speaker set, as shown in FIG. In this case, it is not possible to obtain a sufficient surround effect by only providing speaker sets for L and R channels located on the left and right in front of M. In particular, the surround playback system that uses a monaural 1-channel surround signal is characterized by expressing the sound field behind the listener and the movement of the sound image. In the conventional technology, a rear speaker must be installed. The effect could not be demonstrated.

[0005]

As described above, in the prior art, in the surround reproduction system using the rear surround signal, it is necessary to install the rear speaker in the rear of the listener, There is a problem that it is not possible to obtain the same stereophonic effect as in the original surround reproduction by reproducing only the speaker. In addition, it was necessary to install a speaker in the center in front of the listener for the surround sound signal of one system for the center.

The present invention has been made in order to solve the above-mentioned problems in the conventional example, and one system for rear which originally requires a rear speaker set even if reproduction is performed only by the front left and right speakers. It is an object of the present invention to obtain a surround signal processing device capable of obtaining a stereophonic effect similar to that of surround reproduction using the surround signal. Similarly, even if the sound is reproduced only by the left and right front speakers, a surround sound effect similar to that of the surround reproduction using the center surround signal, which originally requires the front center speaker, can be obtained. It is also an object to obtain a signal processing device.

[0007]

In order to achieve the above object, according to the present invention, for two speakers in front of a listener at a predetermined position, the original L and R of 2-channel stereo are provided.
In addition to each channel signal of, the sound image localization signal obtained by converting the signal of the rear channel is given,
Alternatively, two pairs of speakers are provided in front, and only one pair of original L and R channel signals is provided to one pair.
The above sound image localization signals are applied to the other pair. By performing such sound image localization, it is possible to perform surround reproduction as if a sound is heard from the rear even if the rear speaker behind the listener does not actually exist. In order to obtain the desired sound image localization signal by converting the rear channels, the transfer characteristics of the respective spaces from the pair of speakers that are actually arranged to the left and right ears of the listener and the rear side where the sound image is localized The calculation is performed using the transfer characteristics of the respective spaces from the speaker placed at one of the two predetermined positions during measurement only to the left and right ears of the listener. That is, a filter operation using a convolver (convolution operation processing circuit) or the like is performed.

In the case of a surround signal having a center channel signal in addition to the rear channel signal, the center channel signal is converted to obtain a sound image localization signal for sound image localization in the front center, and the left and right front speakers are provided. Can be given to. Also in this case, the original L and R channel signals and the signal obtained by converting the rear channel signal can be added and reproduced, or reproduced by another pair of speakers to which only the signal obtained by converting the rear channel signal is given. You may Further, in the case of a surround signal having no rear channel signal but only a center channel signal, the same conversion can be performed.

Further, if the rearward sound image localization position is symmetrical, only one filter is required in the signal conversion circuit for obtaining the sound image localization signal, and by using the inverted phase signal obtained by inverting the output signal. The same effect as when two filters are used can be obtained. Also in the case of the sound image localization position at the front center, the same sound image localization signal may be given to the left and right speakers at the center of the front of the listener, so that one filter in the signal conversion circuit can be used.

That is, according to the present invention, there is provided a surround signal processing device which responds to a three-channel signal of a two-channel stereo left channel signal, a right channel signal, and a rear channel signal for obtaining a surround sound effect. A spatial localization signal for the left channel for localizing one component of a sound reproduced from a pair of speakers actually arranged to the front and right of the listener at a predetermined position to two predetermined symmetrical positions behind the listener. And in order to obtain a spatial localization signal for the right channel, the transfer characteristics of each space from the pair of speakers that are actually arranged to the left and right ears of the listener and the measurement at one of the predetermined rear positions. The rear channel signal is converted by using the transfer characteristics of each space from the speaker arranged only in the left side to the left and right ears of the listener. A signal conversion circuit, a means for adding the left channel spatial localization signal and an inverted signal of the right channel spatial localization signal to the left channel signal, the right channel spatial localization signal and the left channel spatial localization signal And a means for adding an inverted signal of the right channel signal to the right channel signal.

Further, according to the present invention, in order to improve the left channel signal of the two-channel stereo, the right channel signal, the rear channel signal for obtaining the surround sound effect, and the sound localization of the center of the two-channel stereo. The surround signal processing device which responds to the four-channel signal of the center channel signal of the above, and which outputs one component of the sound reproduced from the pair of speakers actually arranged to the left and right in front of the listener at a predetermined position to the rear of the listener. In order to obtain the first spatial localization signal for the left channel and the first spatial localization signal for the right channel for respectively locating at two predetermined positions which are bilaterally symmetric, the listener's The transmission characteristics of each space up to the left and right ears, and the reception from the speaker placed at one of the predetermined rear positions only during measurement. A first signal conversion circuit for converting the rear channel signal using the transfer characteristics of the respective spaces to the left and right ears of the listener, and one component of the sound reproduced from the pair of speakers at the front center of the listener. In order to obtain a second spatial localization signal for the left channel and a second spatial localization signal for the right channel for localizing at a predetermined position, respectively, from the pair of speakers actually arranged to the left and right ears of the listener. Converting the center channel signal by using transfer characteristics of each space and transfer characteristics of each space from a speaker arranged at a predetermined position in the front center only at the time of measurement to the left and right ears of the listener A two-signal conversion circuit, a first spatial localization signal for the left channel, a second spatial localization signal for the left channel, and an inverted signal of the first spatial localization signal for the right channel. Means for adding to the left channel signal, means for adding the first spatial localization signal for the right channel, the second spatial localization signal for the right channel, and an inverted signal of the first spatial localization signal for the left channel to the right channel signal , A surround signal processing device is provided.

Further, according to the present invention, there is provided a surround signal processing device which responds to a 3-channel signal of a 2-channel stereo left channel signal, a right channel signal and a rear channel signal for obtaining a surround sound effect. , A spatial localization for the left channel for localizing one component of the sound reproduced from a pair of speakers actually arranged to the front and right of the listener at a predetermined position to two predetermined symmetrical positions behind the listener In order to obtain a difference signal between the signal and the spatial localization signal for the right channel, the transfer characteristics of each space from the pair of speakers that are actually arranged to the left and right ears of the listener and the two rear predetermined values. The rear channel using the transfer characteristics of the space from the speaker placed in one of the positions only at the time of measurement to the left and right ears of the listener. Signal conversion circuit for converting the difference signal, means for adding the difference signal to one of the left channel signal and the right channel signal, and an inverted signal of the difference signal to the other of the left channel signal and the right channel signal. A surround signal processing device is provided which has an adding means.

Further, according to the present invention, in order to improve the left channel signal of the two-channel stereo, the right channel signal, the rear channel signal for obtaining a surround sound effect, and the sound image localization at the center of the two-channel stereo. The surround signal processing device which responds to the four-channel signal of the center channel signal of the above, and which outputs one component of the sound reproduced from the pair of speakers actually arranged to the left and right in front of the listener at a predetermined position to the rear of the listener. In order to obtain a difference signal between the first spatial localization signal for the left channel and the first spatial localization signal for the right channel for localizing at two predetermined symmetrical positions, the pair of speakers actually arranged is used to obtain the difference signal. The transfer characteristics of the respective spaces to the left and right ears of the listener and the spin placed at one of the two predetermined positions behind the speaker only at the time of measurement. A first signal conversion circuit for converting the rear channel signal by using transfer characteristics of respective spaces from the mosquito to the left and right ears of the listener, and one component of the sound reproduced from the pair of speakers. Transfer characteristics of respective spaces from the pair of speakers actually arranged to the left and right ears of the listener in order to obtain a second spatial localization signal to be localized at predetermined positions in the front center of the listener. A second signal conversion circuit for converting the center channel signal using a transfer characteristic of each space from a speaker arranged at a predetermined position in the front center only during measurement to the left and right ears of the listener; Means for adding a signal and the second spatial localization signal to one of the left channel signal and the right channel signal; and an inverted signal of the difference signal as the second spatial localization signal. And means for applying to the other of the left channel signal and the right channel signal,
There is provided a surround signal processing device having:

Further, according to the present invention, when the left channel signal and the right channel signal of the two-channel stereo are reproduced from the first pair of speakers which are actually arranged on the left and right in front of the listener at a predetermined position. A surround signal processing device that responds to a 1-channel signal that is a rear channel signal for obtaining a surround sound effect by a signal reproduced from a second pair of speakers that are actually arranged on the left and right sides of the listener. In order to obtain a spatial localization signal for the left channel and a spatial localization signal for the right channel for respectively locating the sound reproduced from the second pair of speakers at two symmetrical left and right predetermined positions behind the listener. , A transfer characteristic of each space from the second pair of speakers actually arranged to the left and right ears of the listener,
A signal conversion circuit for converting the rear channel signal by using the transfer characteristics of the respective spaces from the speaker placed at one of the predetermined rear positions only at the time of measurement to the left and right ears of the listener, and the left channel A surround signal processing device comprising: a means for adding a space localization signal for a right channel to an inverted signal of the spatial localization signal for right channel; and a means for adding the spatial localization signal for a right channel to an inverted signal of the spatial localization signal for left channel. Provided.

Further, according to the present invention, when the left channel signal and the right channel signal of the two-channel stereo are reproduced from the first pair of speakers which are actually arranged on the left and right in front of the listener at the predetermined position. In addition, a rear channel signal for obtaining a surround sound effect by a signal reproduced from a second pair of speakers actually arranged on the left and right sides of the listener and a sound image localization at the center of the 2-channel stereo are improved. A surround signal processing device for responding to a 2-channel signal of a center channel signal for
A first spatial localization signal for the left channel and a first spatial localization for the right channel for localizing one component of the sound reproduced from the second pair of speakers to two predetermined symmetrical positions behind the listener. In order to obtain a signal, the transfer characteristics of each space from the second pair of speakers that are actually arranged to the left and right ears of the listener and one of the rear predetermined positions are arranged only at the time of measurement. A first signal conversion circuit for converting the rear channel signal using the transmission characteristics of the respective spaces from the speaker to the left and right ears of the listener, and one of the sounds reproduced from the second pair of speakers. In order to obtain the second spatial localization signal for the left channel and the second spatial localization signal for the right channel for localizing the components to predetermined positions in the front center of the listener, respectively The transfer characteristics of the respective spaces from the pair of speakers to the left and right ears of the listener, and the characteristics of the respective spaces from the speaker placed at a predetermined position in the center of the front only at the time of measurement to the left and right ears of the listener. A second signal conversion circuit for converting the center channel signal using transfer characteristics, a first spatial localization signal for the left channel and a second spatial localization signal for the left channel of the first spatial localization signal for the right channel. A surround signal processing device comprising: means for adding to an inverted signal; and means for adding the first spatial localization signal for the right channel and the second spatial localization signal for the right channel to an inverted signal of the first spatial localization signal for the left channel. Will be provided.

Further, according to the present invention, when the left channel signal and the right channel signal of the two-channel stereo are reproduced from the first pair of speakers which are actually arranged on the left and right in front of the listener at a predetermined position. A surround signal processing device that responds to a 1-channel signal that is a rear channel signal for obtaining a surround sound effect by a signal reproduced from a second pair of speakers that are actually arranged on the left and right sides of the listener. And a difference signal between the left-channel spatial localization signal and the right-channel spatial localization signal for localizing the sound reproduced from the second pair of speakers to two predetermined symmetrical positions behind the listener. In order to obtain the transfer characteristics of each space from the second pair of speakers actually arranged to the left and right ears of the listener, A signal conversion circuit for converting the rear channel signal using the transfer characteristics of the respective spaces from the speaker placed only at one of two predetermined positions only at the time of measurement to the left and right ears of the listener, and the difference signal A surround signal processing device having means for obtaining an inverted signal is provided.

Further, according to the present invention, when the two-channel stereo left channel signal and the right channel signal are reproduced from the first pair of speakers which are actually arranged to the front and left of the listener at the predetermined position. In addition, a rear channel signal for obtaining a surround sound effect by a signal reproduced from a second pair of speakers actually arranged on the left and right sides of the listener and a sound image localization at the center of the 2-channel stereo are improved. A surround signal processing device for responding to a 2-channel signal of a center channel signal for
Difference between the first spatial localization signal for the left channel and the first spatial localization signal for the right channel for localizing the sound reproduced from the second pair of speakers to two predetermined symmetrical positions behind the listener. In order to obtain a signal, the transfer characteristics of each space from the second pair of speakers that are actually arranged to the left and right ears of the listener, and only when measuring at one of the two rear predetermined positions. And a sound reproduced from the second pair of speakers, the first signal conversion circuit converting the rear channel signal by using the transmission characteristics of the respective spaces from the speaker disposed in the above to the left and right ears of the listener. In order to obtain a second spatial localization signal for localizing one component at a predetermined position in the front center of the listener,
The transfer characteristics of the respective spaces from the second pair of speakers that are actually arranged to the left and right ears of the listener, and the speaker that is arranged at a predetermined position in the center of the front side only during measurement. Second signal conversion circuit for converting the center channel signal using the transfer characteristics of the respective spaces to the left and right ears, means for adding the difference signal to the second spatial localization signal, and inversion of the difference signal Means for adding a signal to the second spatial localization signal, the surround signal processing device being provided.

According to the present invention, the surround signal responding to the left channel signal of the 2-channel stereo, the right channel signal, and the 3-channel signal of the center channel signal for improving the central sound image localization of the 2-channel stereo. A left-channel space for processing a component of a sound reproduced from a pair of speakers that are actually arranged to the left and right in front of the listener at a predetermined position at a predetermined position in the front center of the listener. In order to obtain a localization signal and a spatial localization signal for the right channel, the transfer characteristics of each space from the pair of speakers that are actually arranged to the left and right ears of the listener and the measurement at a predetermined position in the front center The center channel signal using the transfer characteristics of each space from the speaker placed only at the time to the left and right ears of the listener. A surround signal processing device having a signal conversion circuit for converting a signal, a means for adding the left channel spatial localization signal to the left channel signal, and a means for adding the right channel spatial localization signal to the right channel signal. Provided

Further, according to the present invention, when the left channel signal and the right channel signal of the two-channel stereo are reproduced from the first pair of speakers which are actually arranged on the left and right in front of the listener at a predetermined position. A surround signal processing device responsive to a center channel signal for improving the sound image localization at the center of the two-channel stereo by a signal reproduced from a second pair of speakers that are actually arranged to the front and left of the listener. Therefore, in order to obtain a spatial localization signal for the left channel and a spatial localization signal for the right channel for respectively locating the sound reproduced from the second pair of speakers at predetermined positions in the front center of the listener, And a transfer characteristic of each space from the second pair of loudspeakers arranged to the left and right ears of the listener and a predetermined position at the front center. Surround signal processing apparatus having a signal conversion circuit for converting said center channel signal using the transmission characteristic of each of the space from the speaker disposed only on time to the left and right ears of the listener is provided.

[0020]

In the surround signal processing device according to the first to fourth aspects of the present invention, the signal conversion circuit converts the rear channel signal into a spatial localization signal for localizing it to an intended position in space, and a stereo signal and the spatial localization. By adding the signal and reproducing from the left and right speakers in front of the listener, the stereophonic effect of the surround reproduction system using the surround signal of one system can be obtained only by the front speaker set without the rear speaker set. be able to. Further, the surround signal processing device according to claims 5 to 8 is different from claim 1 in that a speaker set dedicated to the spatial localization signal is provided separately from the normal speaker set. That is, it is possible to independently adjust the listening angle of a speaker to a listener by obtaining a spatial localization signal reproduced from another set of speakers different from a set of speakers reproducing a 2-channel stereo signal. ing.

Further, in the surround signal processing device according to claims 2, 4, 6, and 8, in addition to the conversion of the rear channel signal, the center channel signal is converted into a spatial localization signal for reproduction at the central position of the stereo arranged speaker. Since the spatial localization signals are added by the adding means and reproduced from the left and right front speakers, the sound image in the front center becomes clear without blurring, and when reproduced together with the video image, from the screen You can get the feeling that the sound is coming out.

In the surround signal processing device according to any one of claims 1 to 4, the spatial localization signals are added to the stereo signals of two channels, and the added output is reproduced from a set of speakers arranged in front of the listener. Therefore, only one speaker set is required, and the cost can be reduced.

Further, in the surround signal processing device according to any one of claims 1 to 8, the conversion circuit reproduces the rear channel signal at symmetrical positions on the left and right rear sides of the listener and in opposite phases, and two spatial localization signals of opposite phases. With this configuration, the sound image localization position can be fixed to the rear position of the listener without any discomfort.

Further, in the surround signal reproducing device according to the third, fourth, and seventh and eighth aspects, the one or two conversion circuits are configured to convert the spatial localization signal of the symmetrical image localization position. The stereo arrangement of the speakers and the sound image localization position can be made symmetrical, and the filtering process in the conversion circuit can be halved.

Further, in the surround reproducing apparatus according to the ninth and tenth aspects, the center channel signal is converted into a spatial localization signal so as to be reproduced at the central position of the stereo arrangement speaker, and the spatial localization signal is added to the two-channel stereo signal or Since the sound is played from the left and right speakers in the front without adding, the sound image in the front center becomes clear without blurring, and when playing with the video image, you can get the feeling that sound is coming out of the screen. it can.

[0026]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining the concept of the present invention. In the figure, as an example of 4 channels, 1 receives stereo signals L and R of 2 channels, a center channel signal C for improving stereo central localization, and a rear channel signal S for obtaining a surround stereophonic effect. hand,
A surround signal processing device for converting the rear channel signal S and the center channel signal C into a spatial localization signal for locating each to a desired position in space for performing surround reproduction surrounding the listener M. The stereo signal L,
By reproducing R and the spatial localization signal from the speakers SP1 and SP2 arranged in front of and to the left of the listener M, the rear speakers SP3 and SP4 and listener M to be originally arranged to the rear and left and right of the listener M are required. This eliminates the need for the center speaker SP5 arranged in the front center part of the, and obtains a surround stereophonic effect. The center channel signal C
In the case where there is no case, only the rear channel signal S is processed, but such an aspect is also included in the present invention. On the other hand, it is possible to process only the center channel signal C without the rear channel signal S.

FIG. 2 is a diagram for explaining the principle of the present invention in which a sound image is localized at an intended position in a space surrounding the listener M by the two speakers SP1 and SP2 in the stereo arrangement described above. The principle of the present invention will be described in detail with reference to FIG. In the figure, the transfer characteristics (frequency response of impulse response) from the left speaker SP1 to the left and right ears of the listener M are now h1L, h1R, and the right speaker SP2.
To the left and right ears of the listener M are designated as h2L and h2R. In addition, the transfer characteristic to the left and right ears of the listener M when the actual speaker is placed at the target localization position x is pL.
Let x and pRx. Here, each transfer characteristic is measured by arranging a speaker and a human head or a dummy head and a microphone at both binaural positions in an anechoic space and subjected to appropriate waveform processing.

Next, the signal conversion circuit 1 whose transfer characteristic is represented by cfLx and cfRx at the source X of the acoustic signal to be localized.
The signals obtained through A and 1B are speaker SPs, respectively.
Consider playing with 1 and SP2. At this time, letting the signals obtained in the left and right ears of the listener M be eL and eR, eL = h1L.cfLx.X + h2L.cfRx.X (1a) eR = h1R.cfLx.X + h2R.cfRx.X.・ It becomes (1b).

On the other hand, the signals obtained at the left and right ears of the listener M when the source X is reproduced from the target localization position are dL and d.
If R, then dL = pLx · X (2a) and dR = pRx · X (2b).

Now, if the signals obtained in the left and right ears of the listener M by the reproduction of the speakers SP1 and SP2 match the signals when the source is reproduced from the target position, the listener M has the speaker at the target position. The sound image will be recognized as if it were. That is, the conditions eL = dL, eR = dR
Then, when X is eliminated from the formulas (1a), (1b), (2b), and (2b), h1L · cfLx + h2L · cfRx = pLx ... (3a) h1R · cfLx + h2R · cfRx = pRx ... (3b) ).

From equations (3a) and (3b), cfLx,
When cfRx is calculated, cfLx = (h2R.pLx-h2L.pRx) / H ... (4a) cfRx = (-h1R.pLx + h1L.pRx) / H ... (4b) However, H = h1L.h2R- h2L ・ h1R (4c)

Therefore, the signal conversion circuits 1A having the transfer characteristics cfLx and cfRx calculated by the equations (4a) to (4c),
If the signal to be localized is processed using 1B (hereinafter referred to as a cancel filter for the position x), the sound image at the target position x can be localized.

Although various concrete methods of realizing the cancel filter can be considered, the present invention shows two methods of realizing using a finite impulse response (hereinafter referred to as FIR) digital filter. Conventionally,
Although there is an example in which similar processing is realized by an analog circuit, it is difficult to perform accurate phase processing, and it is costly to obtain a sufficient effect. The present invention introduces digital processing to obtain a clear effect.

FIG. 3 shows that the signal conversion circuits 1A and 1B having the transfer characteristics cfLx and cfRx, which are obtained by the equations (4a) to (4c), are realized by a single FIR filter process. CfLx, cfRx according to the number of
Is prepared in advance and prepared as a ROM, and its filter coefficient is controlled by using a controller and a ROM storing the coefficient.

FIG. 4 shows a case where the equations (4a) to (4c) are realized by a plurality of FIR filters, and when it is necessary to prepare a plurality of relationships between the speakers SP1 and SP2 and the listener M, for example, The signal conversion circuit 1C relating to the filter coefficients (pLx, pRx) and the filter coefficients (h1L, h1R, h2L, h)
2R) is separated from the signal conversion circuit 1D according to
The filter coefficient (pLx, pRx) is variably controlled with respect to the filter coefficient (h1L, h1R, h2L, h2R) to reduce the capacity of the ROM to be prepared. Note that 2 and 3 indicate adders.

Next, an embodiment of the entire signal conversion circuit according to the present invention will be described. Example 1. FIG. 5 shows the overall configuration of the signal conversion circuit according to the first embodiment. In FIG. 5, reference numeral 10 denotes a left and right total signal Lt in a form in which audio information obtained by adding the center channel signal C at the front center and the surround channel signal S at the rear to the left and right channel signals L and R in front of the listener M is mixed. Denoted at 11 and Rt is a decoder for separating the signals into original four-channel signals, and 11 is an amplitude adjusting and reflected sound adding circuit for these signals.

Reference numeral 12 is an FIR digital filter (convolver) as a signal conversion circuit for converting the center channel signal C into the spatial localization signals Lc and Rc of the front localization so as to reproduce the center channel signal C at the center position of the stereo arrangement speaker, and 13 is the surround. Spatial localization signal Ls for inputting the channel signal S and reproducing in opposite phases at the left and right symmetrical positions of the listener M
In the FIR digital filter (convolver) as a signal conversion circuit for converting into Rs and Rs, the filter coefficient and the adjustment value of the amplitude adjustment / reflected sound adding circuit 11 are made variable by using the controller 14A and the ROM 14B. Also, 15 and 16 are inverters, and 17 to 20.
Are adders, 21 and 22 are switches, and 23 to 26 are output terminals.

In the configuration shown in FIG. 5, the 2-channel stereo signals L and R output from the decoder 10 are output.
And a center channel signal C of 1 channel and a surround (rear) channel signal S of 1 channel,
The FIR digital filters 12 and 13 process the center channel signal C so that the center channel signal C is reproduced at the center position of the stereo-arranged speakers and the surround channel signal S is reproduced at the symmetrical positions on the left and right rear sides of the listener M in reverse phase (see FIG. 7) The stereo signals L and R and the spatial localization signals Lc, Rc, Ls and Rs are added by adders 17 to 20.

By connecting the switches 21 and 22 to the upper side in the figure, two speakers (not shown) arranged in front of the listener M connected to the output terminals 23 to 26 and the listener M similarly. From the two speakers dedicated to the spatial localization signal arranged in front, the stereo signal L
And R, spatial localization signals Lc + Ls-Rs, Rc + Rs-
Ls is reproduced, and the switch 21
And 22 are connected to the lower side in the figure, the output terminal 25
From the two speakers in front of the listener M connected to the speakers 26 and 26, the added signal L + Lc + Ls of the stereo signal and the spatial localization signal
-Rs, R + Rc + Rs-Ls are reproduced.

Example 2. FIG. 6 is an overall configuration diagram of a signal conversion circuit according to the second embodiment corresponding to the first embodiment, which simplifies the filtering process in the sound image localization process. 6, parts that are the same as those in FIG. 5 are given the same reference numerals, and descriptions thereof will be omitted. 27 and 28 are FI of Example 1
FI corresponding to the R digital filters 12 and 13 respectively
R digital filter, 29 is an inverter, 30 to 3
2 indicates an adder.

In the above configuration, as shown in FIG. 7, the FIR digital filter 12 is set to L when the L and R speakers are symmetrically arranged and the sound image localization positions are also symmetrically symmetrical left and right. The filter coefficient of R may be the same, and the coefficient of the center speaker is the same for L and R (Lc = Rc), which can be realized by one filter.

On the other hand, the coefficient of the FIR digital filter 28 for realizing the rear speaker by Ls-Rs can be realized by one filter by taking the difference between the L coefficient and the R coefficient in time series. In FIG. 7, α and θ are the opening angle of the front speaker with respect to the listener M and the opening angle of the sound image position corresponding to the rear speaker. Therefore, by arranging the speaker and the sound image localization position symmetrically, it is possible to realize half the filtering process.

According to the second embodiment, as in the case of the first embodiment, the switches 21 and 22 are connected in the upper direction in the drawing to forward the listener M connected to the output terminals 23 to 26. The stereo signals L and R, the spatial localization signals Lc + Ls-Rs, and Rc + Rs-Ls are respectively output from two speakers (not shown) that are disposed and two speakers dedicated to the spatial localization signal that are similarly disposed in front of the listener M.
And the switches 21 and 2
2 is connected to the lower side in the figure, the output terminals 25 and 2
From the two loudspeakers in front of the listener M connected to 6, the added signal of the stereo signal and the spatial localization signal L + Lc + Ls-R
s, R + Rc + Rs-Ls.

By the method described in each of the above-mentioned embodiments, it is possible to obtain a stereophonic effect which cannot be obtained without using the rear speaker set by using only the front speaker. When performing surround reproduction, it is necessary to adjust the output level of each speaker by a test tone in advance. However, in the L and R speaker reproduction according to the above-described embodiment, the L and R speakers should be arranged at optimum positions. This eliminates the need for adjusting the output levels of the center and surround signals.

In the example of FIG. 7, the rear channel signal is localized in the opposite phase to the rear left and right of the listener M. Generally, in surround playback using one rear surround signal, the rear channel plays back rear left and right in-phase signals from the speaker, but when using sound image localization, the in-phase component at the rear left and right symmetrical positions is located in the head or forward. It tends to be localized, in which case the surround effect cannot be fully exerted.

Therefore, although this problem is solved by using the phase shift or the single delay, the rear channel signals are localized in the left and right opposite phases as a simple method in the above embodiment. By this method, the localization becomes easy to be fixed to the rear position, and a sufficient effect can be obtained. Originally, in a 4-channel matrix surround or the like, a monaural component (LR) is reproduced backward in left and right phases, and there is almost no discomfort due to the backward monaural signal being in reverse phase.

Further, in each of the above embodiments, as shown in FIGS. 5 and 6, the position of the spatial localization is made variable by making the coefficient of the FIR digital filter in the signal conversion circuit variable by using the controller and the ROM. Selecting a coefficient that maximizes the effect from the positional relationship between the speaker that reproduces the spatial localization signal and the listener M, and selecting a coefficient that most closely matches the transfer characteristics of the listener M's head. Etc. are possible.

When the L and R signals are reproduced from the two front speakers, and the spatial localization signal is reproduced from the two front speakers different from the speakers, the speaker dedicated to the spatial localization signal is reproduced. Better effects can be obtained by optimizing the arrangement and characteristics. For example, even when the speakers are not separate cabinets, so-called in-speakers in the same cabinet reproduce the spatial localization signal, and the opening angle and the like can be independently adjusted for optimization.

As shown in FIGS. 5 and 6, when the center channel is reproduced, in the normal reproduction not according to the above embodiment,
Originally, since the display device is placed at the position where the center speaker is placed, the center speaker has to be placed from the left and right ends of the display to the top and bottom of the display, or one of the top and the bottom. At this time, in the former case, the sound image is similar to that in normal stereo reproduction, and it is said that the clarity of the sound image is slightly lowered as compared with the case where a speaker is actually arranged at a required sound image position. In the latter case, there is a gap between the required sound image position and the speaker position. On the other hand, in the present invention, the center channel perfectly simulates the speaker at that position, so that the position of the obtained sound image is accurate and the quality of the sound image is more clear.

Furthermore, according to each of the above embodiments, the cost of the speaker set (speakers, amplifiers, terminals, cables, etc.) can be reduced, and a good surround effect can be obtained.

[0051]

As described above, according to the present invention, one or both of the rear channel signal and the center channel signal are converted into a spatial localization signal that localizes the spatial channel to an intended position, and the stereo signal and the spatial signal are converted. Since the localization signal and the speaker are reproduced from the speaker in front of the listener, a surround reproduction stereoscopic system that uses one rear surround signal even if only the speaker set in front of the listener is unnecessary An effect that a sound effect can be obtained is exhibited. In particular, in the present invention, the spatial localization signals to be given to the left and right speakers, which are formed from the rear channel signals, have opposite phases to each other, so that the sound image is easily fixed at the rear position, and a sufficient surround effect can be obtained. Further, by processing the center channel signal in the same manner and localizing it in front of the listener, it is possible to improve the realism of the sound image in image reproduction and the like.

According to the present invention, the spatial localization signal is reproduced from one set of speakers different from the one set of speakers reproducing the two-channel stereo signals. Therefore, it is possible to independently adjust and optimize the opening angles of the other set of speakers dedicated to the spatial localization signal, and it is possible to obtain a good surround effect.

According to the first to fourth aspects, the spatial localization signal is added to the two-channel stereo signal by the adding means, and the added output is output from the set of speakers arranged in front of the listener. Since the reproduction is performed, there is an effect that the cost of the speaker set can be reduced.

According to the second, fourth, sixth and eighth aspects, the center channel signal in addition to the rear channel signal is converted into a spatial localization signal for localizing to the front center of the listener. As a result, a clear sound image can be obtained at the front center position of the listener, and a more favorable surround effect can be obtained.

Further, according to the structure described in claims 3, 4, 7, and 8, the conversion circuit is configured to convert the spatial localization signal at the symmetrical sound image localization position into a speaker and a sound image in a stereo arrangement. The localization position is made symmetrical and the filtering process can be halved.

According to the ninth aspect of the invention, the center channel signal is converted into a spatial localization signal for localizing in the front center of the listener. A sound image can be obtained, and an excellent surround effect can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a concept of a surround signal reproducing device of the present invention.

FIG. 2 is a configuration diagram illustrating the principle of a surround playback device of the present invention.

FIG. 3 is a specific content explanatory diagram of a cancel filter that realizes the signal conversion circuit of FIG.

FIG. 4 is a specific content explanatory view of another example of the cancel filter that realizes the signal conversion circuit of FIG. 2 different from FIG. 3;

FIG. 5 is a configuration diagram of a signal conversion circuit according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram of a signal conversion circuit according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram of a sound image localization position, which is used for the description of FIGS. 5 and 6;

FIG. 8 is an explanatory diagram of a speaker setting during surround reproduction of a conventional example and a speaker setting in an actual home.

[Explanation of symbols]

1 Surround signal processing device 1A, 1B, 1C, 1D Signal conversion circuit 2, 3, 17-20, 30-32 Adder 10 Decoder 11 Amplitude adjustment and reflected sound addition circuit 12, 13, 27, 28 Signal conversion circuit (FIR) Digital filter) 14A controller 14B ROM 15, 16, 29 Inverter 21, 22 Switch 23-26 Output terminal C Center channel signal L Left channel signal Lc, Rc, Ls, Rs Spatial localization signal Lt, Rt Left and right total signal M Listener R Right channel signal S Rear channel signal SP1 to SP5 Speaker X Source signal x Target sound image localization position

Claims (10)

[Claims] 1. A surround signal processing device which responds to a three-channel signal of a left-channel signal of a two-channel stereo, a right-channel signal, and a rear-channel signal for obtaining a surround sound effect, the listener being at a predetermined position. Space for left channel and space for right channel for respectively locating one component of sound reproduced from a pair of speakers actually arranged in front of and to the left of the listener to two symmetrical positions behind the listener. In order to obtain a localization signal, the transmission characteristics of each space from the pair of speakers that are actually arranged to the left and right ears of the listener and the speaker that is arranged at one of the predetermined rear positions only at the time of measurement. To the left and right ears of the listener, and a signal conversion circuit for converting the rear channel signal using the transfer characteristics of the respective spaces, Means for adding a spatial localization signal for the left channel and an inverted signal of the spatial localization signal for the right channel to the left channel signal, the spatial localization signal for the right channel and an inverted signal of the spatial localization signal for the left channel A surround signal processing device comprising: means for adding to a channel signal. 2. A left channel signal of a 2-channel stereo, a right channel signal, a rear channel signal for obtaining a surround sound effect, and a center channel signal for improving the sound image localization at the center of the 2-channel stereo. A surround signal processing device which responds to a channel signal, wherein one component of a sound reproduced from a pair of speakers actually arranged in front of and to the left of a listener at a predetermined position is provided with two symmetrical left and right components behind the listener. In order to obtain the first spatial localization signal for the left channel and the first spatial localization signal for the right channel for respectively localizing the position, each from the pair of speakers actually arranged to the left and right ears of the listener. And the transmission characteristics of the space between the speaker placed at one of the predetermined rear positions only during measurement and the left and right ears of the listener A first signal conversion circuit for converting the rear channel signal using the transfer characteristics of each space, and for localizing one component of the sound reproduced from the pair of speakers to a predetermined position in the front center of the listener. In order to obtain the second spatial localization signal for the left channel and the second spatial localization signal for the right channel, the transfer characteristics of the respective spaces from the pair of speakers actually arranged to the left and right ears of the listener. A second signal conversion circuit that converts the center channel signal by using transfer characteristics of a space from a speaker arranged at a predetermined position in the front center only at the time of measurement to the left and right ears of the listener, The first spatial localization signal for the left channel, the second spatial localization signal for the left channel, and the inverted signal of the first spatial localization signal for the right channel are the left channel signal. And a means for adding the first spatial localization signal for the right channel, the second spatial localization signal for the right channel, and an inverted signal of the first spatial localization signal for the left channel to the right channel signal. Signal processing device. 3. A surround signal processing device which responds to a three-channel signal of a two-channel stereo left channel signal, a right channel signal, and a rear channel signal for obtaining a surround sound effect, wherein a listener at a predetermined position. Space for left channel and space for right channel for respectively locating one component of sound reproduced from a pair of speakers actually arranged in front of and to the left of the listener to two symmetrical positions behind the listener. In order to obtain the difference signal of the localization signal, the transfer characteristics of each space from the pair of speakers actually arranged to the left and right ears of the listener and the measurement at one of the two rear predetermined positions. A signal for converting the rear channel signal by using the transfer characteristics of each space from the speaker arranged only to the left and right ears of the listener. A conversion circuit, means for adding the difference signal to one of the left channel signal and the right channel signal, and means for adding an inverted signal of the difference signal to the other of the left channel signal and the right channel signal, Surround signal processing device having. 4. A left channel signal of a 2-channel stereo, a right channel signal, a rear channel signal for obtaining a surround sound effect, and a center channel signal for improving the sound image localization at the center of the 2-channel stereo. A surround signal processing device which responds to a channel signal, wherein one component of a sound reproduced from a pair of speakers actually arranged in front of and to the left of a listener at a predetermined position is provided with two symmetrical left and right components behind the listener. In order to obtain a difference signal between the first spatial localization signal for the left channel and the first spatial localization signal for the right channel for localizing each position, the left and right ears of the listener from the pair of speakers actually arranged. To the listener from the transmission characteristics of each space up to and from the speaker placed only at the time of measurement at one of the two rear predetermined positions A first signal conversion circuit for converting the rear channel signal using transfer characteristics of respective spaces up to the left and right ears, and a predetermined position in the front center of the listener for one component of sound reproduced from the pair of speakers. Second for each to be localized
In order to obtain a spatial localization signal, transfer characteristics of each space from the pair of speakers that are actually arranged to the left and right ears of the listener and a speaker that is arranged at a predetermined position in the front center only at the time of measurement. To the left and right ears of the listener, and a second signal conversion circuit for converting the center channel signal using the transfer characteristics of the respective spaces; and the left channel signal for the difference signal and the second spatial localization signal. Surround signal processing, and means for adding to one of the right channel signal, and means for adding an inverted signal of the difference signal to the other of the left channel signal and the right channel signal, and the second spatial localization signal. apparatus. 5. When a left channel signal and a right channel signal of 2-channel stereo are reproduced from a pair of first speakers which are actually arranged on the left and right in front of the listener at a predetermined position, the listener's This is a rear channel signal for obtaining a surround sound effect by a signal reproduced from a second pair of speakers actually arranged on the front left and right sides.
A surround signal processing device responsive to a channel signal, wherein a spatial localization signal for a left channel for localizing a sound reproduced from the second pair of speakers to two predetermined symmetrical positions behind a listener. And a transfer characteristic of each space from the second pair of speakers actually arranged to the left and right ears of the listener in order to obtain a space localization signal for the right channel, and one of the rear predetermined positions. A signal conversion circuit for converting the rear channel signal using the transfer characteristics of the respective spaces from the speaker placed only during measurement to the left and right ears of the listener, and the left channel spatial localization signal to the right Means for adding to the inverted signal of the channel spatial localization signal, and adding the right channel spatial localization signal to the inverted signal of the left channel spatial localization signal Surround signal processing apparatus having a means. 6. When a left channel signal and a right channel signal of 2-channel stereo are reproduced from a pair of first speakers which are actually arranged in front of and on the left and right of a listener at a predetermined position, the listener's A rear channel signal for obtaining a surround sound effect by a signal reproduced from a second pair of speakers actually arranged to the front and left and a center channel signal for improving the sound image localization at the center of the 2-channel stereo. A surround signal processing device which responds to a two-channel signal, wherein a left channel for localizing one component of a sound reproduced from the second pair of speakers to two predetermined symmetrical positions behind a listener. Second pair of speakers that are actually arranged to obtain a first spatial localization signal for right channel and a first spatial localization signal for right channel To the listener's left and right ears, and the transfer characteristics of the respective spaces from the speaker placed at one of the predetermined rear positions only at the time of measurement to the listener's left and right ears. A first signal conversion circuit for converting the rear channel signal by using, and a left channel for localizing one component of the sound reproduced from the second pair of speakers to a predetermined position in the front center of the listener. Transfer characteristics of respective spaces from the second pair of speakers actually arranged to the left and right ears of the listener in order to obtain the second spatial localization signal and the second spatial localization signal for the right channel, A second signal for converting the center channel signal by using the transfer characteristics of the respective spaces from the speaker placed at the predetermined position in the front center only at the time of measurement to the left and right ears of the listener. A conversion circuit, means for adding the first spatial localization signal for the left channel and the second spatial localization signal for the left channel to an inverted signal of the first spatial localization signal for the right channel, and the first spatial localization signal for the right channel And a means for adding the second spatial localization signal for the right channel to an inversion signal of the first spatial localization signal for the left channel. 7. When the left channel signal and the right channel signal of 2-channel stereo are reproduced from a pair of first speakers which are actually arranged in front of and on the left and right of the listener at a predetermined position, the listener's This is a rear channel signal for obtaining a surround sound effect by a signal reproduced from a second pair of speakers actually arranged on the front left and right sides.
A surround signal processing device responsive to a channel signal, wherein a spatial localization signal for a left channel for localizing a sound reproduced from the second pair of speakers to two predetermined symmetrical positions behind a listener. And a transfer characteristic of each space from the second pair of speakers actually arranged to the left and right ears of the listener in order to obtain a difference signal between the spatial localization signals for the right channel and the rear two. A signal conversion circuit for converting the rear channel signal using the transfer characteristics of the respective spaces from the speaker placed at one of the three predetermined positions only at the time of measurement to the left and right ears of the listener, and the inversion of the difference signal A surround signal processing device comprising: means for obtaining a signal; 8. When a left channel signal and a right channel signal of 2-channel stereo are reproduced from a pair of first speakers which are actually arranged in front of and on the left and right of a listener at a predetermined position, the listener's A rear channel signal for obtaining a surround sound effect by a signal reproduced from a second pair of speakers actually arranged to the front and left and a center channel signal for improving the sound image localization at the center of the 2-channel stereo. A surround signal processing device which responds to a two-channel signal, wherein a left-channel first device for localizing a sound reproduced from the second pair of speakers to two predetermined symmetrical positions behind a listener. The second pair of speakers actually arranged to obtain a difference signal between the spatial localization signal and the first spatial localization signal for the right channel. To the listener's left and right ears, and the transmission of each space from the speaker placed only at one of the two rear predetermined positions only at the time of measurement to the listener's left and right ears. A first signal conversion circuit for converting the rear channel signal using the characteristics, and a first signal conversion circuit for localizing one component of the sound reproduced from the second pair of speakers to a predetermined position in the front center of the listener. In order to obtain two spatial localization signals, transfer characteristics of each space from the second pair of speakers that are actually arranged to the left and right ears of the listener, and when measuring at a predetermined position in the front center. A second signal conversion circuit for converting the center channel signal by using the transfer characteristics of the respective spaces from the speaker arranged only to the left and right ears of the listener, and the difference signal in the second space. Surround signal processing apparatus having a means for applying to the position signal, means for adding an inverted signal of said difference signal to said second spatial orientation signal. 9. A surround signal processing device which responds to a 3-channel signal of a 2-channel stereo left channel signal, a right channel signal, and a center channel signal for improving central sound image localization of the 2-channel stereo. , A spatial localization signal for the left channel and a right channel for localizing one component of the sound reproduced from a pair of speakers actually arranged to the left and right in front of the listener at a predetermined position to a predetermined position in the center of the front of the listener Transfer characteristics of respective spaces from the pair of speakers that are actually arranged to the left and right ears of the listener in order to obtain a space localization signal for use,
A signal conversion circuit for converting the center channel signal using the transfer characteristics of the respective spaces from the speaker arranged only at the time of measurement at the front center to the left and right ears of the listener, and the left channel A surround signal processing device comprising: means for adding a spatial localization signal to the left channel signal; and means for adding the right channel spatial localization signal to the right channel signal. 10. When the left channel signal and the right channel signal of 2-channel stereo are reproduced from a pair of first speakers which are actually arranged in front of and on the left and right of the listener at a predetermined position, the listener's A surround signal processing device that responds to a center channel signal for improving the sound image localization at the center of the two-channel stereo by a signal reproduced from a second pair of speakers that are actually arranged on the front left and right sides, In order to obtain a spatial localization signal for the left channel and a spatial localization signal for the right channel for localizing the sound reproduced from the pair of two speakers to predetermined positions in the front center of the listener, the above-mentioned arrangement is actually made. The transfer characteristics of each space from the second pair of speakers to the left and right ears of the listener and the distribution at the predetermined position in the front center only at the time of measurement. Surround signal processing apparatus having a signal conversion circuit for converting said center channel signal using the a transmission characteristic of each of the space from the speaker to the left and right ears of the listener.