JPH04143799A - Reverberation adding device - Google Patents

Abstract

PURPOSE:To densely enough generate the reverberation sound on a time base, and to realize a desired natural reverberation by generating a reflected sound by a convolutional operation of the output signal of a first reverberation adding circuit and a time function for showing a reverberation characteristic of a second room. CONSTITUTION:An input signal X1(t) outputted from a digital audio apparatus 1 is inputted to a first reverberation adding circuit 100, and a first reverberation adding circuit 100 generates a signal Y14(t). Subsequently, the signal Y14(t) is inputted to a second reverberation adding circuit 300, and a time function for executing a convolutional operation with the signal Y14(t) by a second reverberation adding circuit corresponds to an initial reflected sound of an impulse response of a general listening room, and by adding an initial reflected sound in a general listening room to each of a direct sound, an initial reflected sound and a rear reverberation sound contained in the signal Y14(t), a signal Y15(t) is generated. In such a way, the reverberation sound becomes denser on a time base, a reverberation characteristic can be generated artificially more exactly, and a more natural sound field can be reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reverberation adding device that artificially adds reverberation to a musical tone signal.

BACKGROUND OF THE INVENTION In recent years, sound field reproduction technology for reproducing various sound fields in ordinary home listening rooms has been actively developed. Sound field reproduction is performed by adding reverberant sound in a sound field (concert pole, live house, etc.) that is artificially desired to be reproduced to a musical sound signal of a music source. Reverberant sound is played back in stereo to create a more realistic feeling, so it is generated for multiple channels and played back by multiple speakers.

FIG. 9 shows an example of a conventional reverberation addition g setting.

FIG. 10 shows an impulse response of a sound field to be generated by the reverberation adding device having the configuration shown in FIG.

In Figure 10, the time parameter T of the impulse response
8. -T8. , and coefficient parameter G8. ~G8. The early reflections of the impulse response of the concert hall are expressed as a time function. Here, only one of the plurality of channels of the reverberation adding device will be explained. The other channels may have similar configurations, or the time functions may differ between channels due to stereo reproduction.

In FIG. 9, 1 is a digital audio device that outputs a digital signal, 2 is a digital audio amplifier, 3 is a speaker, and 4 is a listening space. 800 is a reverberation addition circuit, X3(t) is an input signal from the digital audio equipment 1, 80 is a convolution calculation circuit, and 81 is a delay memo 1c for storing the input signal 82. ~82. ．． is a coefficient multiplier, and 83°84.85 is an adder. 90 is a feedback type reverberation addition circuit, which receives the signal Y from the convolution calculation circuit 80;
32(t) is input. 91 is a delay memory that delays the input signal by a time T; 92 is a coefficient A (tap, Q
<A<1), and 93 is an adder.

In FIG. 9, which explains the mutual relationship and operation of each of the above components, the signal X3ft from the digital audio equipment 1 is
), the delay memory 81 sequentially updates the addresses and stores them for a predetermined time.

Next, the delay memory 81 inputs the input signal X3ft) to T8. ~T8. delayed by l, and the delayed signal X8, ~X
8. ．． Take it out as Among the signals taken out from the delay memory 81, X8. ~X8. Well, the multiplier 821~
82. The early reflected sound Y31 is added by the adder 83 via
1t) is obtained. X8, . . . ~X8° is a multiplier 82. ．．
1-82. The signal Y32(t
). The signal Y32(t) is fed back to the reverberation adding circuit 9.
It is input to 0. When the feedback type reverberation adding circuit 90 receives a signal with a level of 1 as an input signal, it is delayed by a time of T by a delay memory 91, and at the same time as output, it is made into a signal of a level A by a coefficient multiplier 92 and fed back to the delay memory 91. . Below, the interval of T is A2. A3.
. . . appears in order as the rear reverberation signal Y33(t).

Parameters A and T are set so that the rear reverberation signal Y33(t) reproduces the attenuation characteristic of the rear reverberation sound of the general sound listening room.

Furthermore, the signal X3(t), which is a direct sound, is added by the adder 85.
, early reflection sound Y31(t), and rear reverberation signal Y33(
t ) to obtain an output signal Z3(t), which is input to the digital audio amplifier 2 and radiated to the listening space 4 by the speaker 3.

The other channels of the reverberation adding device also radiate the reverberant sound of each channel in the same manner as described above.

This allows the sound field of a concert hall to be reproduced in a general listening room, allowing listeners to listen to music with a sense of realism.

However, when looking at the reverberation characteristics due to the impulse response of an actual Connosert Hall, there are a very large number of innopulse responses, and if we try to realize these by convolution operation, the convolution operation in the convolution operation circuit 80 of FIG. The number of calculation points m becomes extremely large. Due to hardware limitations in the reverberation adding devices currently in practical use, the number of convolution points m is limited to less than the actual number of impulse responses, and convolution is used to generate early reflections. ing. The rear reverberant sound that follows the early reflections is reflected many times on the walls of the listening space, and looking at the impulse response, there are quite a lot of them. I wanted to,
Since it is difficult to generate rear reverberation sound using the convolution calculation circuit 80, which has a limited number of convolution calculation points, it is generated and added using a separate reverberation adding circuit.

FIG. 10 shows the impulse response of a reverberation adding device in which the number of convolution calculation points is actually limited.

Even if the reverberation is limited as shown in Figure 10, when listening in a general listening room, dense reverberation can be generated on the time axis because the listening room itself is affected, and the quality of the reverberation is satisfactory. . FIG. 11 shows an example of an impulse response in an actual listening room, and FIG. 12 shows an example of an impulse response when a reverberation adding device that limits reverberation sound is tested in a listening room.

Problems to be Solved by the Invention In such conventional reverberation adding devices, the number of convolution calculation points is limited based on the premise of listening in a general listening room. In a space, you can expect reverberation to occur within the listening space itself, and there is an unnatural feeling in which the reverberant sounds can be heard separated in time.

However, if the number of convolution calculation points, that is, the number of m points in the configuration shown in FIG. 9, is increased, the hardware will also increase in proportion to the number. Further, since convolution operations are not performed using individual coefficient multipliers, but are generally performed using serial sequential processing, there is a limit to the number of convolution operations that can be processed within a certain amount of time.

Therefore, in a listening space where there is very little reverberation, such as inside a vehicle, the conventional configuration cannot reproduce reverberation that is sufficiently dense on the time axis, and the quality of the reverberation cannot be satisfied.

The present invention solves the above-mentioned problems, and aims to provide a reverberation adding device that can generate reverberant sound densely enough on the time axis in a listening space with very little reverberation, and can realize the desired natural reverberation. purpose.

Means for Solving the Problems - In order to achieve the above object, the reverberation adding device of the present invention performs a convolution operation of convolving an input signal with a time function representing the early reflected sound of the reverberation characteristics of the first room. arithmetic circuit,
a first reverberation addition means for forming a reverberation addition circuit that generates a rear reverberation sound following the early reflected sound; and convolution of the output signal of the first reverberation addition circuit with a time function representing the reverberation characteristics of the second room. and second reverberation adding means for generating reflected sound by calculation.

In addition, in order to reproduce a more natural sound field, a convolution calculation circuit that performs a convolution operation between the input signal and a time function representing the early reflected sound of the reverberation characteristics of the first room, and a rear reverberation that follows the early reflected sound. The first one has a reverberation adding circuit that generates sound.
a convolution calculation circuit that performs a convolution operation between the output signal of the first reverberation addition circuit and a time function representing the early reflected sound of the reverberation characteristics of the second room; and a rear reverberation that follows the early reflected sound. and second reverberation adding means for developing a rear reverberation adding circuit that generates sound.

Effect of the present invention With the above-described configuration, the reverberation sound obtained by the convolution operation of the second reverberation addition means is added to the reverberation sound obtained by the first reverberation addition means, thereby producing dense reverberation sound on the time axis. By adding a reverberation addition circuit that adds rear reverberation sound to the generation of reverberation sound in the second room, the reverberation sound in the second room can be made denser and longer. (do.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings. Here, as well as the description of the conventional example, only one of the plurality of channels of the reverberation adding device will be described. The other channels have similar configurations, but the time functions differ between the channels because they are reproduced in stereo.

First, a first embodiment of the present invention will be described.

FIG. 1 is a block diagram of a reverberation adding device according to a first embodiment of the present invention.

FIGS. 2, 3, and 4 are impulse response diagrams at various parts of the reverberation adding device shown in FIG. 1.

In FIG. 1, 1 is a digital audio device that outputs a digital audio signal, 2 is a dinotal audio amplifier, 3 is a speaker, and 4 is a listening space.

XHt) is the output signal of digital audio device 1, 1
00 is the first reverberation addition circuit, 10 is the convolution calculation circuit,
11 is a delay memory for storing input signals; 121 to 1;
21 is a coefficient multiplier, and 13, 14, and 15 are adders.

20 is a feedback type reverberation adding circuit to which the output signal Y12D) of the convolution calculation circuit 10 is input. 21 is a delay memo 1c that delays the input signal by a time T. 22 is a coefficient A (
23 is an adder.

300 is a second reverberation addition circuit, which uses the output signal Y14(t) of the first reverberation addition circuit 100 as an input signal,
Add reverberation using convolution operations. 31 is a delay memory, 32. ~32. is a coefficient multiplier, and 33.34 is an adder.

The operation of the reverberation adding device configured as described above will be explained below.

In FIG. 1, the human input signal XI(t) output from the digital audio device 1
is input.

The first reverberation addition circuit 100 generates the signal Y14(t) in the same manner as the reverberation addition circuit described in the related art. FIG. 2 shows the impulse response of the first reverberation adding circuit 100.

Next, the signal Y14(t) is manually input to the second reverberation adding circuit 300. Signal Y14(t) from the second reverberation adding circuit 300
The time function for performing the convolution operation corresponds to the early reflection sound of the impulse response of the general listening room, and is shown in FIG. In other words, the time parameter T3 + -73-1 coefficient parameter G of the impulse response in Fig. 3
3. ~G3. It represents the time function of the reverberation characteristics of a general listening room. The second reverberation adding circuit 300 generates a signal Y15(t) by adding the early reflected sound in a general listening room to each of the direct sound, early reflected sound, and rear reverberant sound included in the signal Y14(t). will be generated.

By adding the signal Y14(t) from the first reverberation addition circuit 100 and the signal Y15(t) from the second reverberation addition circuit 300 using the adder 34, the output signal ZHt
) can be obtained. The output signal Zlft) is input to the digital audio amplifier 2 and radiated to the listening space 4 via the speaker 3. The other channels of the reverberation adding device also output the reverberant sound of each channel in the same manner as the above operation.

FIG. 4 shows the impulse response of the output signal Zl(t).

As shown in FIG. 4, the output signal Zl(t) is a signal Y14(t) obtained by adding concert hall reverberation to the direct sound.
This is the result of adding the reverberant sound of a general listening room. Therefore, the output signal Z1(1) is the signal Y14(t)
On the other hand, it becomes denser on the time axis, and the same effect as when reproducing the reverberation characteristics of a concert hall in a general listening room can be obtained even in a listening space with very short reverberation such as a car interior. I can do it.

As described above, according to the reverberation adding device of the first embodiment of the present invention, the first reflected sound and the subsequent rear reverberant sound are generated.
Since the second reverberation addition circuit and the second reverberation addition circuit that generates the reflected sound in the listening room are continued, the same effect can be achieved even in the passenger compartment as when reproducing hall characteristics in the listening room. or can be obtained.

Next, a second embodiment of the present invention will be described.

In this embodiment, by reproducing the reverberation characteristics of the listening room with higher precision than in the first embodiment,
It reproduces even more natural reverberation.

FIG. 5 is a block diagram of a reverberation adding device according to a second embodiment of the present invention. Here, as in the above explanation, only one of the plurality of channels of the reverberation adding device will be explained. The other channels have similar configurations, but the time functions are different for each channel due to stereo reproduction.

6, 7, and 8 are impulse response diagrams at various parts of the reverberation adding device shown in FIG. 5.

In FIG. 5, ■ is a digital audio device that outputs a digital signal, 2 is a digital audio amplifier, 3 is a speaker, and 4 is a listening space.

X2(t) is the output signal of the digital audio device 1,
400 is a first reverberation adding circuit, 40 is a convolution calculation circuit, 41 is a delay memory for storing input signals, 42+~
42. is a coefficient multiplier, and 43, 44, and 45 are adders. 50 is a feedback type reverberation adding circuit, and a convolution calculation circuit 40
The signal 4Y22(1) from 4Y22(1) is input. 51 is a delay memory for delaying the input signal by a time T; 52 is a fi
A coefficient multiplier for multiplying by A (0<A<1); 53 is an adder; 600 is a second reverberation adding circuit;
0 is the convolution calculation circuit, and the output Y of the first reverberation addition circuit
24(t) is the input signal. 61 is day-time memory,
62. ~62. is a coefficient multiplier, and 63, 64.65 are adders. 70 is a feedback type reverberation adding circuit to which the signal Y26(1) from the convolution calculation circuit 60 is input. 71 is a delay memory that delays the input signal by a time T; 72
is a coefficient multiplier that multiplies the coefficient A (0<A<1), 7
3 is an adder.

The operation of the reverberation adding device configured as described above will be explained below.

In FIG. 5, the input signal X2(t) output from the digital audio device 1 is sent to the first reverberation adding circuit 40.
It is input to 0.

The first reverberation addition circuit 400 obtains a signal Y24ft) by the same operation as the first reverberation addition circuit 100 of the first embodiment, and outputs it to the convolution calculation circuit 60.

FIG. 6 shows the impulse response of the first reverberation adding circuit 400.

In the convolution calculation circuit 60 of FIG. 5, the time function used to perform the convolution calculation with the signal Y24(1) corresponds to the early reflection sound of the impulse response of a general listening room. The impulse response is shown in FIG. Time parameter T6 in FIG. ~T61, coefficient parameter G6. ~G6. It represents the time function of the early reflected sound of the reverberation characteristics of a very common Norisuni/Groom. The convolution arithmetic circuit 60 processes signals X6. out of the signals taken out from the delay memory 61. ~
X6, or the adder 63 via the multipliers 621 to 62
are added to obtain the early reflected sound Y25(t). X6.4
1-X6. is the multiplier 62. . 1 to 62, the signal Y26(t) added by the adder 64 is obtained.

The sound field characteristics of a general listening room may include rear reverberation sound with a long reverberation time that cannot be expressed by the time function of the blue tint calculation circuit 60. Therefore, the signal Y26(t) is input to the feedback type reverberation adding circuit 70 to generate rear reverberation sound. In the feedback type reverberation addition circuit 70, if a signal with a level of 1 is added as an input signal, it is delayed by a time T by the delay memory 71, and at the same time as it is output, it becomes a signal with a level by the coefficient multiplier 72, and is input to the delay memory 71. will be returned.

Thereafter, the signals A21, A3+, . . . appear in order at intervals of T as rear reverberation signals Y27ft). Parameter A,
T is set so as to reproduce the attenuation characteristic of the rear reverberation signal Y27ft) or the rear reverberation sound of a general listening room. Note that the feedback type reverberation adding device 70 is not limited to this configuration.

The output Y24ft of the first reverberation addition circuit 400 and the initial reflection sound Y2 of the second room by the second reverberation addition circuit 600
5(t) and the rear reverberation signal Y27ft) in an adder 65, an output signal 22(t) is obtained. The output signal Z2(t) is input to the D/D amplifier 2, and is radiated to the listening space 4 via the speaker 3. The other channels of the reverberation adding device also output the reverberant sound of each channel in the same manner as the above operation.

FIG. 8 shows the impulse response of the output signal Z2(t).

As shown in Fig. 8, the output signal Z2(t) is the signal Y24ft) which is the reverberant sound of the concert hall, and the early reflection sound Y25(t) and the rear reverberation signal Y27(t) of the general listening room are added. ing. The output signal Z2D) is denser on the time axis than the output Zl(t) of the first embodiment, and has a reverberation characteristic similar to that in a general listening room when reproducing the reverberation characteristics of a concert hall. It generates more accurate doubts. This makes it possible to generate a loudspeaker in a listening space with very short reverberation, such as inside a car.
This can be made more natural than the first invention.

As described above, according to the reverberation adding device according to the second embodiment of the present invention, the first reflected sound and the subsequent rear reverberation sound are generated.
The reverberation addition circuit is arranged to continue with the early reflection sound that simulates the reverberation characteristics of the listening room, and the second reverberation addition circuit that generates the subsequent (rear reverberation sound), creating a more natural sound field. Can be played.

Note that the present invention can be implemented with the same functional configuration regardless of whether digital signals or analog signals are used.

Effects of the Invention As is clear from the description of the embodiments above, the present invention provides a convolution calculation circuit that performs a convolution calculation of an input signal and a time function representing early reflection sound of the reverberation characteristics of a first room; A first reverberation adding means has a reverberation adding circuit that generates a rear reverberant sound following the sound, and a reflected sound is generated by a convolution operation of the output signal of the first reverberation adding circuit and a time function representing the reverberation characteristics of the second room. Since the second reverberation addition circuit that generates the reverberation characteristics is continuously arranged, the reverberation characteristic of a concert hall can be reproduced in a general listening room, while the reverberation characteristics of a car interior can be reproduced. A convolution calculation circuit that performs a convolution operation between the input signal and a time function representing the early reflection sound of the reverberation characteristics of the first room; A first reverberation addition means having a reverberation addition circuit that generates reverberation sound; and a convolution operation between the output signal of the first reverberation addition circuit and a time function representing an early reflected sound of the reverberation characteristics of the second room. a second convolution calculation circuit that performs
Since the second reverberation adding means is continued, the reverberation characteristics of the second room can be reproduced more accurately, and a reverberation adding device capable of reproducing a natural sound field can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a reverberation adding device according to a first embodiment of the present invention, FIG. 2 is an impulse response diagram in the first reverberation adding circuit, and FIG. 3 is a diagram showing the second reverberation adding circuit. 4 is an impulse response diagram of the same reverberation adding device, FIG. 5 is a diagram showing the configuration of the reverberation adding device of the second embodiment of the present invention, and FIG. 6 is a diagram showing the same. The impulse response diagram of the first reverberation addition circuit, Figure 7 is the impulse response diagram of the second reverberation addition circuit, Figure 8 is the impulse response diagram of the same reverberation addition device, and Figure 9 is the conventional reverberation addition circuit. A block diagram showing the configuration of the device, Fig. 10 is an impulse response diagram of the same reverberation adding circuit, Fig. 11 is a response diagram showing an example of an impulse response in a general listening room, and Fig. 12 shows a conventional reverberation adding device. FIG. 4 is a response diagram showing an example of an impulse response when listening in a general listening room. 10.40.60... Convolution calculation circuit, 20°50.70... Feedback type reverberation adding device, 100,3
00.400,600...Reverberation addition circuit. Name of agent: Patent attorney Akira Kokaji and two others Figure 2 Figure 3 Figure 4 Figure 61 Figure 7 Figure 8

Claims (2)

[Claims] (1) A convolution operation circuit that performs a convolution operation between an input signal and a time function representing an early reflected sound in the reverberation characteristics of the first room, and a rear reverberation adding circuit that generates a rear reverberant sound following the early reflected sound. a first reverberation adding means having
A reverberation adding device comprising: second reverberation adding means for generating reflected sound by convolving the output signal of the reverberation adding circuit with a time function representing the reverberation characteristics of a second room. (2) A convolution calculation circuit that performs a convolution operation between the input signal and a time function representing the early reflected sound in the reverberation characteristics of the first room, and a rear reverberation adding circuit that generates a rear reverberation sound following the early reflected sound. a first reverberation adding means having
a convolution calculation circuit that performs a convolution operation between the output signal of the reverberation addition circuit and a time function representing the early reflected sound in the reverberation characteristics of the second room; and a rear reverberation addition that generates a rear reverberation sound following the early reflected sound. A reverberation adding device comprising a second reverberation adding means having a circuit.