JP3611158B2 - Surround signal processing apparatus and signal processing method therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surround reproduction for reproducing a multi-channel audio signals, in particular, a surround signal processing apparatus and for enabling reproduction of multi-channel audio by readily computers at home such as a display and two-channel stereo speakers The present invention relates to a signal processing method .
[0002]
[Prior art]
(Technical background)
Conventionally, in order to reproduce stereophonic sound that can obtain a sound field or sound image localization from the listener's position to the rear, two speakers in front of a stereo arrangement (front speakers) and speakers in a rear arrangement for surround ( (Rear speakers) A minimum of three speakers, one or two, is required. When playing back to the center channel, such as surround playback using a single surround signal or high-definition 3-1. Furthermore, one or two speakers are required as center speakers, and amplifiers and cables for the channels to be reproduced are required.
[0003]
That is, as speaker settings necessary for surround playback, for example, as shown in FIG. 14A, the left and right channel speaker sets positioned in front of the listener LM and the left and right channels are positioned. A rear speaker set for the surround of the SL and SR channels, or in addition to this, a center speaker of the C channel in the front center is required.
[0004]
However, in a general home, it is difficult to arrange the rear speaker and the center speaker in terms of space and cost. As shown in FIG. 14B, an actual speaker set is a listener. Only the L and R channel speaker sets positioned on the left and right in front of the LM are provided, and in that case, a sufficient surround effect cannot be obtained. In particular, the surround playback system using monaural surround signals (one rear surround signal) was characterized by expressing the sound field behind the listener and expressing the movement of the sound image. If it was not installed, the effect could not be demonstrated.
[0005]
However, recently, a surround signal processing apparatus that can obtain a stereophonic sound effect similar to the case where a rear speaker set is provided by reproduction using only the front left and right speakers has been considered.
[0006]
(Conventional technology)
This gives the sound image localization signal obtained by converting the rear channel signal in addition to the original L and R channel signals of two-channel stereo to the two speakers in front of the listener at a predetermined position. Or, two pairs of speakers are provided in front, only one of the original L and R channel signals is given to one pair, and the sound image localization signal is given to the other pair. is there. By performing such sound image localization, it is possible to perform surround reproduction so that sound can be heard from behind even if there is no rear speaker behind the listener.
[0007]
In order to convert the rear channel and obtain the desired sound image 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 rear where the sound image is to be localized The calculation is performed using the transfer characteristics of each space from the speaker arranged at one of the two predetermined positions only during measurement to the listener's left and right ears. That is, a filter operation using a convolver (convolution operation processing circuit) or the like is performed.
[0008]
The configuration and principle of a conventional surround signal processing apparatus using the sound image localization signal will be described as follows.
FIG. 15 is a configuration diagram for schematically explaining a system of a surround signal processing apparatus using a sound image localization technique. In the figure, reference numeral 100 denotes, as an example of four channels, two-channel stereo signals L and R, a center channel signal C for improving the stereo center localization, and a rear channel signal S for obtaining a surround stereophonic effect. Accordingly, the surround signal processing apparatus converts the rear channel signal S and the center channel signal C into sound image localization signals that localize each at an intended position in space in order to perform surround reproduction surrounding the listener LM.
The stereo signals L and R and the sound image localization signal are reproduced from the speakers SP1 and SP2 arranged at the front left and right of the listener LM, so that the rear speakers SP3 and the rear speakers SP3 arranged at the left and right of the listener LM that are originally required. SP4 eliminates the need for the center speaker SP5 disposed at the front center of the listener LM and the rear speaker SP6 disposed at the rear center of the listener LM, thereby obtaining a surround stereophonic sound effect.
[0009]
FIG. 16 is a diagram for explaining the principle of localization of a sound image at an intended position in a space surrounding the listener LM by using two speakers SP1 and SP2 arranged in stereo. 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 LM are h1L and h1R, and the right speaker SP2 to the left and right ears of the listener LM. The transfer characteristics are h2L and h2R. Also, let pLx and pRx be the transfer characteristics of the listener LM to the left and right ears when an actual speaker is placed at the target localization position x. Here, each transfer characteristic is obtained by performing an appropriate waveform processing on a measurement result obtained by arranging a speaker, a human head or a dummy head, and microphones at both ear positions in an anechoic space.
[0010]
Next, let us consider that the signals obtained by passing the signal conversion circuits 101A and 101B whose transfer characteristics are represented by cfLx and cfRx at the source X of the acoustic signal to be localized are reproduced by the speakers SP1 and SP2, respectively. At this time, let eL and eR be signals obtained at the left and right ears of the listener LM.
[0011]
eL = h1L.cfLx.X + h2L.cfRx.X (11a) eR = h1R.cfLx.X + h2R.cfRx.X (11b)
[0012]
On the other hand, if the signals obtained at the left and right ears of the listener LM when the source X is reproduced from the target localization position are dL and dR,
dL = pLx · X (12a) dR = pRx · X (12b)
[0013]
If the signals obtained at the left and right ears of the listener LM by the reproduction of the speakers SP1 and SP2 coincide with the signal when the source is reproduced from the target position, it is as if the listener LM has the speaker at the target position. The sound image will be recognized.
That is, if the condition eL = dL, eR = dR and the equations (11a), (11b), (12a), (12b) and X is deleted,
[0014]
h1L.cfLx + h2L.cfRx = pLx (13a) h1R.cfLx + h2R.cfRx = pRx (13b)
[0015]
And when cfLx and cfRx are obtained from the equations (13a) and (13b),
cfLx = (h2R · pLx−h2L · pRx) / H (14a) cfRx = (− h1R · pLx + h1L · pRx) / H (14b) where H = h1L · h2R−h2L · h1R (14c)
[0016]
Therefore, the signal to be localized is processed using the signal conversion circuits 101A and 101B (hereinafter referred to as a localization filter for the position x or simply a filter) of the transfer characteristics cfLx and cfRx calculated by the equations (14a) to (14c). Then, the sound image at the target position x can be localized.
[0017]
That is, the surround signal may be processed and reproduced from the front speakers SP1 and SP2 by a pair of localization filters whose rear speaker installation position is the sound image localization position x. Then, for example, a surround signal processing device as shown in FIGS. 17 and 18 is configured by combining a plurality of pairs of localization filters.
[0018]
FIG. 17 shows the two-channel stereo signals L and R output from the surround decoder SD, the one-channel center channel signal C, the two-channel surround (rear) channel signals SL and SR, and the rear channel signals SL and SR. It is a device that performs sound image localization processing so as to reproduce at symmetrical positions on the left and right rear sides of the listener.
[0019]
In this apparatus, a pair of localization filters (filters 101A, 101B, 101A, 101B) are provided for each of the rear channel signals SL, SR, and the sound image is localized at the positions of the virtual rear speakers SP3, SP4 shown in FIG. . That is, the L, R, and C signals and the signal subjected to the sound image localization processing are added and reproduced from the pair of speakers SP1 and SP2 in front. In this apparatus, it is necessary to perform sound image localization processing with a total of four filters on the rear channel signals SL and SR.
[0020]
FIG. 18 shows a conventional apparatus corresponding to a surround reproduction method using a monaural rear surround signal. In this configuration, a pair of localization filters (filters 101A and 101B) for one channel are provided, and the rear surround signal S is localized at the position of the virtual rear speaker SP6 shown in FIG. 15 with a total of two filters. I was letting.
[0021]
[Problems to be solved by the invention]
By the way, the above-described conventional surround signal processing apparatus performs signal processing based on the head-related transfer function (HRTF) from the pair of front speakers to the listener's ears and the HRTF from the rear surround speaker. The surround signal component is used to localize the sound image to the listener's left and right sides or left and right rear by a pair of front speakers without a rear speaker.
Therefore, a listener who satisfies the HRTF condition, that is, the distance from the left and right speakers or the arrival time condition can obtain the target surround sound effect of the above-mentioned conventional apparatus, but is located in a place outside the condition. The listener cannot enjoy the effect.
For example, when a plurality of people try to listen side by side or to listen alone, there is a problem that the range for obtaining the effect is very limited.
[0022]
Accordingly, the present invention aims to provide a surround signal processing apparatus and a signal processing method thereof that broaden such restrictions and cope with the above problems.
[0023]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention comprises means described in the following (1) to ( 6 ).
That is,
(1) A rear surround signal inputted from a pair of transducers arranged substantially symmetrically in front of the listener in the left-right direction is subjected to sound image localization by the filter means to the listener's left and right sides or to the left and right. In the surround signal processing apparatus to be reproduced,
The pair of Toranju - a time difference equivalent signal based on the difference of the distances of each of to the listening position of the side than the ideal position of the listener from the support, the output of said lateral listening position side of the speaker of the filter means A surround signal processing apparatus characterized in that a delayed signal is extracted from the signal, and the delayed signal is added again to the output signal.
(2) The input rear surround signal from a pair of transducers arranged substantially symmetrically in front of the listener in the left-right direction is subjected to sound image localization by the filter means to the listener's left and right sides or to the left and right. In the surround signal processing apparatus to be reproduced,
A signal corresponding to a time difference based on a difference in distance from the pair of transducers to the listening position lateral to the listener 's ideal position is delayed from the rear surround signal. A surround signal processing apparatus characterized in that a signal obtained by adding a rear surround signal is input to the filter means.
(3) In the surround signal processing apparatus according to claim 1, a pseudo stereo circuit in which a pair of left and right surround signals reproduced from the pair of transducers are made uncorrelated with each other on the front stage side of the filter means. A surround signal processing apparatus comprising an amplitude adjusting means for providing an amplitude difference between a pair of rear surround signals in the circuit.
(4) In the surround signal processing device according to claim 3, the reflected sound is added to the pair of rear surround signals to be pseudo-stereo by adjusting the amplitude of a plurality of rear surround signals having different delay times and adding them. A surround signal processing apparatus further comprising a sound adding circuit.
(5) An input rear surround signal from a pair of transducers arranged substantially symmetrically in front of the listener in the left-right direction is subjected to sound image localization to the listener's left and right sides or left and right front and rear by filtering. In the surround signal processing method to be reproduced,
A signal corresponding to a time difference based on a difference in distance from each of the pair of transducers to the side listening position from the ideal position of the listener is output from the speaker on the side listening position side of the filtering process. A surround signal processing method characterized by including a step of extracting a delayed signal from the signal and adding the delayed signal to the output signal again.
(6) A rear surround signal input from a pair of transducers arranged substantially symmetrically in front of the listener in the left-right direction is subjected to sound image localization to the listener's left and right sides or left and right front and rear by filtering. In the surround signal processing method to be reproduced,
A signal corresponding to the time difference based on the difference in distance from the pair of transducers to the listening position lateral to the listener 's ideal position is delayed from the rear surround signal, and the delayed signal and the rear signal are delayed. A surround signal processing method characterized by including a step of adding a surround signal to the signal and performing the filtering process on the added signal.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described by way of preferred examples with reference to the drawings.
The present invention has been made based on the following verification by the present inventors.
In other words, a listener who is equidistant from the front speaker can obtain a surround effect even if the listener moves slightly forward and backward, and in the sound component reaching the listener, the reflected sound characteristics of the room It has been verified that the surround effect can be obtained even when there is a component that reaches the speaker at an equal time.
[0025]
In other words, even if the listener is not in the original ideal position, the sound reaches the left and right ears at equal distances or equal time from the left and right speakers, and the sound is the dominant signal. It is verified that a surround sound effect can be obtained. The present invention has been made by utilizing such a phenomenon.
[0026]
FIG. 1 is a diagram for explaining the basic principle of the present invention and is a diagram assuming a case where three listeners are lined up with respect to the speakers SPL and SPR.
In particular, in this embodiment, it is assumed that a surround effect is obtained by using a television in a general household.
In this case, the distance between the left and right speakers at which the television screen can be fully viewed is considered as the range in which the viewer sits. Here, the distance w between the front speakers is assumed to be 80 cm, and three persons (A , B, C) is assumed to be 2 m from the speaker SPL, SPR sitting side by side, and the distance E from the center of the head where the three are side by side is assumed to be 60 cm.
[0027]
In this way, first, among the three listeners A, B, and C, the central person B that is equidistant from the left and right speakers SPL and SPR is originally subjected to the same technique as in the prior art. A sound image localization filter is created so as to obtain the following effect.
[0028]
Next, for the two left and right people A and C, the following is considered.
In this case, since A and C are symmetric with respect to the center person B, only A will be described. In order to simplify the explanation, the size of the listener's head is ignored with respect to the distance L, and a time difference is considered at the center of the head.
[0029]
Here, the distance TL from the left speaker SPL to the center of the head of the listener A is
TL = (L 2 + (0.2 m) 2) 1/2 = 2.009995 (m)
Similarly, the distance TR from the left speaker SPR to the center of the head of the listener A is
TR = (L 2 + (1 m) 2) 1/2 = 2.23606 (m)
Since the difference between TL and TR is 22.7 cm and the sound speed is 340 m / sec at room temperature, this is a time difference t = 0.667 msec.
[0030]
Therefore, if a signal delayed by t time from the left speaker is supplied, the left listener A can obtain the Sarand effect. Similarly, since C is also in a symmetric position, a signal delayed by t time from the right speaker SPL may be supplied.
[0031]
Here, a case will be considered where left and right listeners A and C are added with a signal delayed by t time from the left and right speakers so as to satisfy the effect. The listener B in the center listens to the signal of the equal distance or equal time twice from the left and right speakers, delayed by t time, both of which are signals that achieve the original surround effect.
In addition, it is generally said that it is difficult to distinguish a similar signal that continues in a few ms or less.
Therefore, a substantially normal surround effect can be obtained.
[0032]
Next, considering the left listener A, the normal left speaker SPL, the right speaker SPR paired therewith, and signals SPL (t) and SPR (t) delayed by t time, respectively. Can be heard at the timing shown in FIG.
When viewed under such conditions, the listener A was able to recognize the surround effect with the signal subjected to the time delay processing, but this effect cannot be recognized without the time delay processing. It was.
This confirms that the presence of other signals SPL, SPR (t) is masked. Similarly, the listener C on the opposite side was confirmed.
[0033]
Therefore, based on the above verification results, in a system in which the listener uses a pair of front speakers, the listener is located at an equal distance from the left and right speakers, and performs sound image localization using the HRTF, it deviates from its ideal position. For the listener, the signal from the nearest speaker is delayed by a time difference corresponding to the difference in distance from the left and right speakers and added to the original signal, so that the sound image localization conditions are satisfied and surround An effect is obtained.
Then, if a signal delayed by the same time is added to the left and right signals, the surround effect can be obtained at the ideal position and the listeners located at the left and right.
[0034]
Next, an embodiment made based on the basic concept described above will be described.
FIG. 3 is a schematic block diagram of the surround signal processing apparatus according to the first embodiment.
The apparatus shown in the figure reproduces a surround sound from a pair of speakers SPL and SPR arranged at a front position substantially symmetrical with respect to a listener based on an input of a monaural sound signal S for rear. In order to perform signal processing so that the pair of surround signals are not correlated with each other, a comb filter for generating a sum signal and a difference signal of the delayed signal of the rear surround signal S and the signal before the delay is provided. The pseudo stereo circuit 1 and a pair of surround sounds output by the pseudo stereo circuit 1 having a non-correlation with each other are localized at a rear position that is substantially symmetric in a wide range of positions compared to the prior art. And a sound image localization circuit 2 capable of performing the same.
[0035]
Here, the pseudo stereo circuit 1 gives a delay amount to the surround signal S and outputs it as a delay signal S ′, and an adder 12 that outputs a sum signal S + S ′ added as the original surround signal S. And an adder 13 for outputting a difference signal S-S 'obtained by subtracting the delay signal S' from the original surround signal S.
[0036]
The sound image localization circuit 2 also includes an adder 21 for obtaining an addition output of the sum signal and the difference signal output as a pair of surround signals from the pseudo stereo circuit 1, and a subtraction output of the sum signal and the difference signal. A second subtractor 22 that receives the output of the adder 21 and performs a convolution calculation process such as a convolver; and a second filter 23 that receives the output of the subtractor 22 and performs a convolution calculation process such as a convolver. A filter 24, a differencer 25 that subtracts the first filter output and the second filter output, an adder 26 that adds the first filter output and the second filter output, and an output of the differencer 25 A delay circuit 27 for delaying the output of the delay circuit 27 and the output of the subtractor 25, a delay circuit 29 for delaying the output of the adder 26 by about 1 mS, And an adder 30 for adding the output of the extension circuit 29 and an output of the adder 26.
[0037]
The transfer characteristics P and N of the first and second filters 23 and 24 are as follows.
P = (F + K) / (S + A) (1.1)
N = (F−K) / (S−A) (1.2)
(Where S is a transmission characteristic from a pair of speakers to the ear on the same side of the listener, A is a transmission characteristic from the pair of speakers to the listener and the ear on the other side, and F is a surround signal sound image localization. The number of transmissions from the desired position to the ear on the same side of the listener, and K is set to the transfer function from the position where the surround signal is to be localized to the ear on the opposite side of the listener). The range of surround playback can be set with a width at the localization position.
[0038]
As described above, in the configuration shown in FIG. 3, the input surround sound S is a single mono-multi signal, so that the input signal S is passed through the pseudo stereo processing circuit 1 formed of a comb filter so as to be correlated. One side obtains an addition output with the signal S ′ delayed by the delay circuit 11 by the adder 12, and the other obtains a subtraction output with the signal S ′ delayed by the adder 13 to obtain the subsequent sound image localization circuit 2. The first filter 23 and the second filter 24 are processed so as to localize the sound source to a desired position by the aforementioned arithmetic processing, and these signals are the main components of the present invention. This is supplied to the delay circuit 27 and the adder 28 and the delay circuit 29 and the adder 30 so as to obtain a surround effect over a wider range than before.
[0039]
Next, a surround signal processing apparatus according to the second embodiment of the present invention will be described with reference to FIG. In this embodiment, in order to obtain a surround effect over a wide range, which is the main effect of the present invention, and to increase the sense of further expansion of the sound field, the amplitude of the signals input to the first and second filters 23 and 24 is increased. A pair of delay circuits 11a and 11b for delaying these signals is provided by providing a difference, so that the delay time of the subsequent filter can be freely changed.
[0040]
That is, as an amplitude adjusting means for giving an amplitude difference between a pair of surround signals, an amplitude adjusting amplifier 4a is provided on the input side to the first filter 23 in the preceding stage of the delay circuit 11a, and the second filter 24 is connected to the second filter 24. On the input side, an amplitude adjusting amplifier 4b is provided in the preceding stage of the delay circuit 11b, and the amplitude adjustment rate is varied to give an amplitude difference.
In particular, in the apparatus of the present embodiment, for example, the input level to each of the filters 123 and 124 may be changed according to the listening room environment. In the live room, the sound field is produced in various ways, such as by reducing the input of the first filter 123 and clarifying the virtual sound image. It is what I did.
[0041]
Further, when actual signal processing is performed by a DSP (digital signal processor), there is only one system of surround sound, so one delay line is sufficient and efficient. Furthermore, reflected sound can be added by appropriately extracting signals with different delay times from this delay line, a sense of distance can be obtained in the virtual sound image, and there is a sense of presence that can be heard in a hall or movie theater. can get. If this configuration is specifically shown as the third embodiment, the configuration shown in FIG. 5 is obtained.
[0042]
That is, FIG. 5 shows a reflected sound adding circuit 5 for adding a reflected sound to a pair of rear surround signals to be pseudo-stereo by adjusting and adding amplitudes of a plurality of linear surround signals having different delay times, and a delay circuit 27. 1 shows a surround signal processing device that can expand a sound field and an area where the effect can be obtained by using an adder circuit 28, a delay circuit 29, and an adder circuit 30.
[0043]
The reflected sound adding circuit 5 takes out a plurality of different rear surround signals S from the delay line 11c as delay means, appropriately adjusts the amplitude by an amplitude adjusting amplifier 51, and adds them by an adder 52, thereby adding a pseudo signal. A wide range of sound field reproduction in a variety of acoustic spaces, from listening in a large space such as a dome to a mini theater, which is a small space, by adding reflected sound to a pair of rear surround signals to be stereo. Can be reproduced very well in the region.
In addition, it was set as the structure which can simulate completely the frequency phase characteristic of a head transmission characteristic.
[0044]
Next, FIG. 6 shows an apparatus according to the fourth embodiment. In the surround reproduction apparatus using the rear surround signal of one monaural system shown as the conventional example in FIG. 12, the upstream side of the adder is In this configuration, delay circuits 27 and 29 each having a delay amount of about 1 mS are provided. In this case, these delay amounts may be different from each other according to the intended effect.
Even in such a configuration, as in the case described above, it is possible to expand the area in which the listener enjoys the surround effect more than before.
[0045]
Further, FIG. 7 shows an apparatus according to the fifth embodiment, which has the same configuration as that of FIG.
According to the apparatus of this embodiment, only one delay circuit is required, the circuit scale can be reduced, and only one addition operation is required, and the signal processing step can be simplified.
By recording the signal processed in such a processing step on a recording medium such as a disk or a tape, when the signal is reproduced, the above-described processing becomes unnecessary at the time of reproduction.
[0046]
By the way, recently, since personal computers (hereinafter referred to as PCs or personal computers) are rapidly becoming multimedia, it is widely used to handle moving images and sounds on PCs.
A transmission method and a processing method when the above-described surround signal processing method is processed using a personal computer will be described with reference to FIG.
As shown in the figure, the personal computer 106 to which the surround signal processing program and the surround source are supplied via the disk drive 104 or the network terminal 105 is an MMX (INTEL P55C extended instruction set: an instruction set for a specific application. CPU (corresponding to a controller) 106a equipped mainly with digital signal processing such as image / sound efficiently, RAM 106b used as a buffer at the time of data processing, disk drive 104 or network terminal A data converter 106c for converting data input via the audio signal 105, and an audio interface 106d for supplying a signal processing result to a speaker disposed at a substantially symmetrical position in front of the listener. .
[0047]
The network terminal 105 uses a protocol called TCP / IP (Transmission Control Protocol / Internet Protocol) to transmit or receive data in units of packets. This network is known as the Internet. A header including an address is added to the packet to identify the host.
When transferring the processing program to another host, the processing program is set in the disk drive and the packet is transferred by the above protocol.
When the processing program is received from another host, the processing program is received in units of packets by the above protocol and stored in the memory RAM 106a.
[0048]
Next, the operation of the configuration shown in FIG. 8 will be described with reference to the flowchart shown in FIG. FIG. 9 shows a case in which a program loading command (command) is input from a keyboard (not shown) in a state in which a disc on which a surround signal processing program is recorded is set in the disc drive 104. It can be seen that the program is loaded (when a command is input, it is determined that the program is loaded). The program data is read and supplied to the internal RAM of the CPU 106a (step S2). When the program load is completed, the program load flag is set (step S3) and the process is terminated. At this time, since the CPU 106a is MMX compatible, signal processing can be performed at high speed.
[0049]
Next, a play command is input from a keyboard (not shown) in a state where a disc on which a surround source is recorded is set in the disc drive 104. When starting in this state, the program is set by checking the program load flag in step S1. (NO in step S1), the process proceeds to step S4, where the first track (special track) of the disc is accessed and the subcode indicating the type of the disc is read to determine that it is a surround source. If YES, the data is read from the next track and decoded in step S5, the processing data is set in the audio interface 106d (step S6), the process returns to step S5, and the decoding process and the like are repeated. The audio interface 106d performs D / A conversion on the received data at a predetermined sampling period, and supplies it to the speaker as an analog signal. If NO in step S4, the performance impossibility is displayed (step S7), and the process ends.
[0050]
Here, the surround signal processing program performed in the decoding process in the above-described step S5 includes, for example, processing steps shown in FIG. This processing step is a processing step corresponding to FIG.
That is, in step S100, a multi-channel audio signal including a rear surround signal is decoded, and in subsequent step S101, a filter coefficient based on the head-related transfer function is set for each channel of the pair of left and right rear surround signals. Sound image localization processing is performed by filter processing for realizing a convolver. Further, the processed signals are delayed by about 1 ms in steps S102 and 103, respectively, and after adding these signals in step S104, a signal having a surround effect spread to the listener is output in FIG. 8 via output step S105. To the audio interface 106d shown.
[0051]
Further, if corresponding to FIG. 7, the processing steps as shown in FIG. 11 may be adopted.
That is, in step S200, the multi-channel audio signal including the rear surround signal is decoded, and in the next step S201, the rear surround signal is delayed by about 1 ms, and the delayed signal and the undelayed signal are added, In step S202, a sound image localization process is performed by a filter process that realizes a convolver in which a filter coefficient based on the head-related transfer function is set for each channel of the rear surround signal. Further, in step S203, the left or right signal (L or R signal) and the center signal (C signal) are added to each processed signal in step S203, and the audio interface 106d shown in FIG. Output to.
[0052]
Furthermore, as a recording medium such as a disk, a disk having a plurality of tracks formed on the recording surface, each track being divided into a plurality of sectors, and a unique address assigned to each sector is used. A first data area in which the surround signal processing program is recorded in a plurality of sectors; a second data area in which a surround source is recorded in a sector different from the plurality of sectors; and the first and second data on a recording surface By providing a TOC (TABLE OF CONTENTS) area in which data indicating that there is an area is provided, the surround signal processing program is recorded as the first data, and the surround source is recorded as the second data. It is possible to provide computer software that records both surround signal processing programs and surround sources. That.
[0053]
FIG. 12 is a diagram schematically showing a plane of a data-recorded disc shown as a preferred embodiment of the recording medium. A disc D shown in FIG. 12 is an optical recording medium having a diameter of 120 mm, which is defined by a standard disc called CD plus (System Identifiier is CD PLUS) or an enhanced music CD, for example, from the inner circumference toward the outer circumference. The first lead-in area D1, the first data area D2, the first lead-out area D3, the second lead-in area D4, the second data area D5, and the second lead-out area D6 are arranged substantially concentrically in this order. Has been. Here, the first lead-in area D1 constitutes a first TOC for recording the address of each data of the first data area D2, and the second lead-in area D4 is each of the second data area D5. A second TOC for recording data addresses and the like is configured.
[0054]
The operation of the CPU 106a shown in FIG. 8 when the disk shown in FIG. 12 is used as a recording medium will be described with reference to the flowchart shown in FIG.
When a composite disc 7 having two data areas as shown in FIG. 12 is set in the disc drive 4 and a play instruction is input from a keyboard (not shown), first, a flag indicating whether or not the program has been loaded is displayed. Judgment is made by looking (step S11), and if NO, the program data area of the CPU is known by looking at the first lead-in area D1 of the inner first data area D2 shown in FIG. 12, and recorded in the first data area D2. The loaded programs are sequentially loaded into the internal RAM of the CPU and continued until the program loading is completed (steps S12 to S15). If it is determined that the program is absent (YES in step S13), the process ends.
[0055]
When the program load is completed (YES in step S15), the test data stored after the program of the first data is read and loaded into the RAM 106b (step S16) (however, this step is not performed if not). . Then, the decoding program is activated to perform test decoding processing (step S17). As a result, when it is determined that the data has been correctly decoded (the correct decode signal is supplied in pairs with the test data in advance, it is determined whether the data is correct by comparing them). Set a flag indicating that the current position is over (step S19), and return to step S11. If NO in step S18, the performance impossibility is displayed on the display and the process ends.
If YES is determined in step S11, that is, if the program has already been loaded, the second data recorded in the second data area D5 is read (read), and the end of file (EOF) is read. The decoding process similar to that described above is performed until it is, and output to the audio interface 106d (steps S21 to S24). If YES in step S22, the process ends.
[0056]
【The invention's effect】
According to the present invention, the listener can enjoy the surround effect in a wider range than before.
In particular, according to the invention described in claim 3, in addition to the effect described in claim 1, in particular, the sense of antiphase can be reduced by manipulating the amplitude of the rear surround signal. A surround space with an improved sense of spread can be created.
According to the invention described in claim 4, in addition to the effect described in claim 1, in particular, since the reflected sound is added, the sense of distance of the sound image can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the basic principle of the present invention.
FIG. 2 is a timing diagram of left and right reproduction sounds.
FIG. 3 is a schematic block diagram of a surround signal processing apparatus according to the first embodiment of the present invention.
FIG. 4 is a schematic block diagram of a surround signal processing apparatus according to a second embodiment of the present invention.
FIG. 5 is a schematic block diagram of a surround signal processing apparatus according to a third embodiment of the present invention.
FIG. 6 is a schematic block diagram of a surround signal processing apparatus according to a fourth embodiment of the present invention.
FIG. 7 is a schematic block diagram of a surround signal processing apparatus according to a fifth embodiment of the present invention.
FIG. 8 is a configuration diagram according to an embodiment in the case where the present invention is implemented by a personal computer as an apparatus for implementing the surround signal processing method of the present invention.
FIG. 9 is a flowchart showing an operation in the configuration shown in FIG. 13;
10 is a flowchart showing processing steps of a surround signal processing program corresponding to the configuration of FIG.
11 is a flowchart showing processing steps of a surround signal processing program corresponding to the configuration of FIG. 7;
FIG. 12 is a diagram schematically showing a plane of a data-recorded disc used as a recording medium.
13 is a flowchart showing the operation of the CPU 6a shown in FIG. 13 when the disc shown in FIG. 17 is used as a recording medium.
FIG. 14 is a diagram for explaining a general surround system;
FIG. 15 is a diagram for explaining conventional sound image localization processing;
FIG. 16 is a diagram for explaining the principle of sound image localization processing;
FIG. 17 is a configuration diagram of a conventional surround signal processing apparatus.
FIG. 18 is a configuration diagram of a conventional surround signal processing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pseudo stereo circuit 2 Sound image localization circuit 4a, 4b, 51 Amplitude adjustment amplifier 11, 11a, 11b, 27, 27a, 27b, 29, 52 Delay circuit 12, 13, 21, 26, 28, 30 Adder 22, 25 Differentiator 23 First filter 24 Second filter 104 Disk drive 105 Network terminal 106 Personal computer 123, 124 Filter D Disk SPL, SPR Speaker

Claims (6)

Surround that a rear surround signal inputted from a pair of transducers arranged substantially symmetrically in front of the listener in the left-right direction is reproduced with the sound image being localized to the left or right side of the listener or left and right front and back by the filter means. In the signal processing device,
The pair of Toranju - a time difference equivalent signal based on the difference of the distances of each of to the listening position of the side than the ideal position of the listener from the support, the output of said lateral listening position side of the speaker of the filter means A surround signal processing apparatus characterized in that a delayed signal is extracted from the signal, and the delayed signal is added again to the output signal. Surround that a rear surround signal inputted from a pair of transducers arranged substantially symmetrically in front of the listener in the left-right direction is reproduced with the sound image being localized to the left or right side of the listener or left and right front and back by the filter means. In the signal processing device,
A signal corresponding to a time difference based on a difference in distance from the pair of transducers to the listening position lateral to the listener 's ideal position is delayed from the rear surround signal. A surround signal processing apparatus characterized in that a signal obtained by adding a rear surround signal is input to the filter means. 2. The surround signal processing apparatus according to claim 1, wherein a pair of left and right surround signals reproduced from said pair of transducers are uncorrelated with each other on the front side of said filter means, and the circuit. An surround signal processing apparatus comprising amplitude adjusting means for providing an amplitude difference between a pair of rear surround signals. 4. The reflected signal adding circuit according to claim 3, wherein the reflected sound is added to the pair of rear surround signals to be pseudo-stereo by adjusting the amplitude and adding a plurality of rear surround signals having different delay times. A surround signal processing apparatus, further comprising: Surround that reproduces an input rear surround signal from a pair of transducers arranged substantially symmetrically in front of the listener in the left-right direction or left-right front-rear direction by filtering. In the signal processing method,
A signal corresponding to a time difference based on a difference in distance from each of the pair of transducers to the side listening position from the ideal position of the listener is output from the speaker on the side listening position side of the filtering process. A surround signal processing method characterized by including a step of extracting a delayed signal from the signal and adding the delayed signal to the output signal again. Surround that reproduces the input rear surround signal from a pair of transducers arranged substantially symmetrically in front of the listener in the left-right direction or the front-rear direction by filtering. In the signal processing method,
A signal corresponding to the time difference based on the difference in distance from the pair of transducers to the listening position lateral to the listener 's ideal position is delayed from the rear surround signal, and the delayed signal and the rear signal are delayed. A surround signal processing method characterized by including a step of adding a surround signal to the signal and performing the filtering process on the added signal.

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