JP2000069599A - Reverberation sound generating device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce correlation among channels, and to obtain a natural reverberation sound by individually providing multi-channel comb-shaped filters for an R channel and an L channel, and setting each feedback delay of those comb-shaped filters as individual values for the R channel and the L channel. SOLUTION: Each feedback delay of R channel comb-shaped filters 11R, 12R, 13R, and 14R and L channel comb-shaped filters 11L, 12L, 13L, and 14L is individually set for the R channel and the L channel. Also, each feedback delay of R channel whole band pass filters 16R and 17R and L channel whole band pass filters 16L and 17L is individually set for the R channel and the L channel. Thus, each feedback delay of the comb-shaped filters and the whole band pass filters is set as different values for the R channel and the L channel, and the R channel and the L channel are individually processed so that monaural input signals can be made stereophonic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverberation generating apparatus and method for obtaining a natural reverberation by reducing the correlation between channels even if the input signal is monaural, thereby obtaining a natural reverberation.

[0002]

2. Description of the Related Art A reverberation sound generator shown in FIG. 1 is generally used to generate a reverberation sound, which combines a comb filter (Comb Filter) devised by Schrader and an all-pass filter (All-Pass Filter). The reverberation sound generation device shown in FIG. 5 generates reverberation sound by multi-channel surround reproduction when the surround sound is one monaural channel.

That is, the reverberation generating apparatus shown in FIG.
Comb filters 11 to 14 for four channels, an adder 15 for mixing the outputs of the comb filters, all-pass filters 16 and 17, and an all-pass filter 17
And an adder 18 for adding the input signal IN to the output of the adder 18 and outputting the result.

Here, each comb filter will be described by taking the comb filter 11 as an example.
A signal path through which an input signal passes is provided by inserting a loop constituted by a delay circuit having a delay time τ1, a feedback path having an amplifier having a gain g1 smaller than 1 and an adder. The signal IN is successively attenuated while being repeatedly circulated, so that the reverberation signal of the input signal IN is obtained at the output side. The comb filter 12
The delay time of the delay circuit and the gain of the amplifier are τ2 and g2,
The delay time of the delay circuit of the comb filter 13 and the gain of the amplifier are set to τ3 and g3, and the delay time of the delay circuit of the comb filter 14 and the gain of the amplifier are set to τ4 and g4.

As an all-pass filter, two all-pass filters 16 and 16 are used in order to increase the density of reverberation signals in a natural sense and to obtain practically sufficient diffusion of reverberation.
17 two-stage connection configurations are employed. To explain using the all-pass filter 16 as an example, the all-pass filter 16
The reverberation sound passing through the adder 15 is further circulated in a delay circuit having a delay time τ5, a loop having an amplifier having a gain of g5, and a loop having an amplifier having a gain of -g5 so as to produce many reverberation signals. ing. The delay time of the delay circuit of the all-pass filter 17 and the gain of the amplifier are set to τ6, g6, and −g6.

Since the above-described reverberation sound generating apparatus is basically a monaural circuit, it is necessary to convert the reverberation sound into stereo in some way. For this purpose, the monaural reverberation must be decorrelated, and the circuits shown in FIGS. 6 and 7 can be considered.

FIG. 6 shows a configuration in which the all-pass filter of FIG. 5 is connected in three stages, and an all-pass filter 19L, 1 is connected to the output terminal of the all-pass filter 17 as a third-stage all-pass filter.
9R is provided to make LR independent. The delay time of the delay circuit of the all-pass filter 19L and the gain of the amplifier are set to τ7, g7, and −g7. Similarly, the delay time of the delay circuit of the all-pass filter 19R and the gain of the amplifier are τ7 ′ and g7 ′. And -g7 '.

In FIG. 7, a delay circuit 20 is provided at the output end of the all-pass filter 17 so as to give different delays to the monaural reverberation sound output from the output end of the all-pass filter 17 by LR. .

[0009] In Japanese Patent Application Laid-Open No. 5-40493,
By using the premixing means, the LR-independent reverberation generating means, and the postmixing means, it is possible to generate reverberation with little coloration, high density, and spaciousness. Furthermore, Japanese Patent Application Laid-Open No. 6-1614831 proposes a setting device which does not require the operator to set a large number of parameters, and can set desired reverberation filter parameters with a simple operation.

[0010]

However, any of the above-mentioned methods has a problem that it is difficult to obtain naturalness because the reverberation sound generation itself is monaural processing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. Reverberation sound generators are provided separately for the L channel and the R channel, and the L channel and the R channel are processed independently. Accordingly, it is an object of the present invention to provide a reverberation sound generating apparatus and method capable of reducing the correlation between channels and obtaining a natural reverberation sound.

[0012]

In order to achieve the above object, a reverberation generator according to the present invention comprises: a multi-channel comb filter for adding reverberation of a monaural one-channel input signal; A reverberation sound generator including an all-pass filter for increasing the reverberation signal generation density by inputting the sum output of the comb filter output, wherein the multi-channel comb filter is divided into an L channel and an R channel. The present invention is characterized in that the feedback delays are individually provided and each feedback delay of these comb filters is set to an individual value for the L channel and the R channel.

Further, the all-pass filter is provided separately for the L channel and the R channel, and each feedback delay of the all-pass filter is set to an individual value for the L channel and the R channel. It is.

[0014] The present invention is further characterized by further comprising an output section for crossing and outputting the outputs of the all-pass filters provided separately for the L channel and the R channel.

Further, the all-pass filter has a multistage connection configuration.

Further, in the reverberation sound generating method according to the present invention, an input step of inputting a monaural one-channel signal;
An L-channel reverberation adding step for adding a reverberation of a signal input through the inputting step, and an L-channel for increasing a generation density of a reverberation signal through the L-channel reverberation adding step A reverberation signal generation density increasing step, an R channel reverberation sound adding step for adding a reverberation sound of the signal input through the input step, and a reverberation signal through the R channel reverberation sound adding step. Increasing the R-channel reverberation signal generation density for increasing the generation density, and outputting the L-channel and R-channel signals through the L-channel and R-channel reverberation signal generation density increasing steps. Things.

Further, in the output step, the signals of the L channel and the R channel through the reverberation signal generation density increasing steps of the L channel and the R channel are crossed and output.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG.
1 is a configuration diagram illustrating a reverberation sound generation device according to an embodiment. In FIG. 1, the same parts as those of the conventional example shown in FIG. The reverberation generator according to the present embodiment uses a comb-shaped filter that adds reverberation to reduce the correlation between channels (the characteristic of the vector ω is expressed by the equation H (ω) = exp (−jωτi) / ( l-gi · e
xp (−jωτi)) where gi is a gain and τi is a delay time. Are separately provided for the L channel and the R channel.

That is, the comb filters 11L, 12L, 13L and 14 are used as L-channel comb filters.
L, and comb filters 11R, 12R, 13R, and 14R are provided as comb filters for the R channel, and each feedback delay of these comb filters is set to an individual value for the L channel and the R channel. I have. For example, the L-channel comb filters 11L, 12L, 1
The delay time of each of the 3L and 14L delay circuits is τ1, τ2, τ
3, τ4, whereas the delay time of each delay circuit of the R-channel comb filters 11R, 12R, 13R, 14R is set to τ1 ′, τ2 ′, τ3 ′, τ4 ′. The gain of the L channel is g1, g2,
g3 and g4, while the R channel is g1 ′, g
2 ′, g3 ′, and g4 ′.

Further, an all-pass filter for increasing the reverberation signal generation density (the characteristic of the vector ω is expressed by the following equation: H (ω) = exp (−jωτi) · (1-gi · e)
xp (jωτi) / (1-gi · exp (−jωτ)
i)) where gi is the gain and τi is the delay time. Are separately provided for the L channel and the R channel. That is, as the L-channel all-pass filter, the all-pass filter 1
6L and 17L, and all-pass filters 16R and 17R as R-channel all-pass filters. The feedback delays of these all-pass filters are set to individual values for the L and R channels.
For example, L-channel all-pass filters 16L and 17L
While the delay time of each delay circuit is τ5 and τ6,
The delay time of each delay circuit of the all-pass filters 16R and 17R of the R channel is set to τ5 ′ and τ6 ′.
g6, −g6, while the R channel is g5 ′,
−g5 ′, g6 ′, and −g6 ′. Each feedback delay of the comb filter is, for example, 20 to 100 m.
Different values are set for the L channel and the R channel during s. Each feedback delay of the all-pass filter is set to a different value for the L channel and the R channel, for example, between 2 and 20 ms.

As described above, according to the reverberation sound generating apparatus according to the first embodiment in which the conventional reverberation sound generating apparatus shown in FIG. Each feedback delay of the all-pass filter is L
By setting different values for the channel and the R channel and processing the L and R channels independently, the correlation between the channels can be reduced, and a natural reverberation can be obtained.

(Second Embodiment) FIG. 2 is a block diagram showing a reverberation sound generating apparatus according to a second embodiment. 2, the same parts as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. The reverberation generator according to the second embodiment crosses the output of the L-channel all-pass filter 17L and the output of the R-channel all-pass filter 17R with respect to the first embodiment shown in FIG. Further comprising an output unit 21 for outputting
Thereby, the correlation between the L channel and the R channel can be adjusted.

(Third Embodiment) FIG. 3 is a block diagram showing a reverberation generating apparatus according to a third embodiment. 3, the same parts as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. The reverberation generator according to the third embodiment has a comb-shaped filter for adding reverberation as in the first embodiment shown in FIG.
The L channel and the R channel are individually provided, and as the all-pass filter, the all-pass filter 16,
A multi-stage connection configuration of 17, 22, and 23 is adopted. The delay time of each delay circuit of the all-pass filters 22 and 23 is set to τ9 and τ10, and the gain of each amplifier is also g.
9, -g9, g10, and -g10. The number of filter connections greatly affects the quality of reverberation. In the third embodiment, by increasing the number of filter stages,
It can increase the density and eliminate the echo feeling.

(Fourth Embodiment) FIG. 4 is a flowchart for explaining a reverberation sound generating method according to a fourth embodiment. As shown in FIG. 4, in the reverberation generating method according to the present embodiment, first, a monaural one-channel signal is input (step 1), and the comb filters 11L and 11 shown in FIG.
Reverberation is added to the L channel using 2L, 13L, 14L, etc. (step 2). Further, using the all-pass filters 16L and 17L shown in FIG.
The reverberation signal generation density through the reverberation adding step of the channel is increased (step 3). Also, as in steps S2 and S3, the R channel is also shown in FIG.
Comb filters 11R, 12R, 13R, 14R
A reverberation sound is added using such as (Step 4). further,
The reverberation signal generation density is increased using the all-pass filters 16R and 17R shown in FIG. 1 (step 5). Then, the signals obtained in steps S3 and S5 are output (step S6).

As described above, by independently processing the L channel and the R channel, the correlation between the channels can be reduced, and a natural reverberation can be obtained. In the output step in step S6, the outputs of the L and R channels are crossed and output as in the second embodiment shown in FIG. Can be adjusted.

[0026]

As described above, according to the reverberation sound generating apparatus and method of the present invention, the processing of adding reverberation sound and increasing the generation density of reverberation signals is performed independently for each LR channel. Even if the input signal is monaural, the correlation between channels can be reduced to stereo, and natural reverberation can be obtained. Further, by crossing the output signals of the respective LR channels, an arbitrary correlation value can be set between the LRs.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a reverberation sound generation device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a reverberation sound generation device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating a reverberation sound generation device according to a third embodiment of the present invention.

FIG. 4 is a flowchart illustrating a reverberation sound generation method according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram showing a reverberation sound generation device according to a conventional example.

FIG. 6 is a configuration diagram showing a reverberation sound generation device according to another conventional example.

FIG. 7 is a configuration diagram showing a reverberation sound generation device according to still another conventional example.

[Explanation of symbols]

11L, 12L, 13L, 14L L-channel comb filters 11R, 12R, 13R, 14R R-channel comb filters 16L, 17L L-channel all-pass filters 16R, 17R R-channel all-pass filters 21 Output unit 22 , 23 all-pass filter S1 input step S2 L-channel reverberation sound addition step S3 L-channel reverberation signal generation density increase step S4 R-channel reverberation sound generation step S5 R-channel reverberation signal generation density increase step S6 output step

Claims (6)

[Claims] 1. A multi-channel comb filter for adding reverberation sound of a monaural one-channel input signal, and an addition output of the outputs of these comb filters for increasing the density of reverberation signals. In a reverberation generating apparatus provided with an all-pass filter, the multi-channel comb filters are separately provided for the L channel and the R channel, and the feedback delays of these comb filters are individually provided for the L channel and the R channel. A reverberation sound generating apparatus characterized by setting a value of 2. The reverberation sound generating apparatus according to claim 1, wherein the all-pass filters are provided separately for the L channel and the R channel, and each feedback delay of the all-pass filter is provided for the L channel and the R channel. A reverberation generating apparatus characterized by setting to individual values. 3. The reverberation sound generating apparatus according to claim 2, further comprising: an output unit that crosses and outputs the outputs of the all-pass filters provided separately for the L channel and the R channel. Characteristic reverberation generator. 4. The reverberation sound generating apparatus according to claim 1, wherein said all-pass filter has a multistage connection configuration. 5. An input step of inputting a monaural one-channel signal, an L-channel reverberation adding step for adding a reverberation of the signal input through the input step, and an L-channel reverberation. An L-channel reverberation signal generation density increasing step for increasing a reverberation signal generation density through the adding step, and an R-channel reverberation sound adding for adding a reverberation sound of the signal input through the input step The step of increasing the density of the reverberation signal of the R channel for increasing the density of the reverberation signal through the step of adding the reverberation sound of the R channel; and the step of increasing the density of the reverberation signal of the L channel and the R channel. Outputting an L channel and an R channel signal through the reverberation sound generating method . 6. The reverberation sound generating method according to claim 5, wherein the outputting step crosses the signals of the L channel and the R channel through the steps of increasing the reverberation signal generation densities of the L channel and the R channel. A reverberation sound generation method, characterized in that the reverberation sound is output.