JPH0471400B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a natural sound field reproducing device that can obtain a three-dimensional sound field similar to the reverberation characteristics of a hall or the like during reproduction.

FIG. 1 is a block diagram of a conventional reverberation generator. In FIG. 1, 1 is an L channel input terminal, and 2 is an R channel input terminal. This L
The L channel input signal input from the channel input terminal 1 and the R channel input signal input from the R channel input terminal 2 are added by an adder 3.

The output of the adder 3 is sent to adders 8 and 9 through a delay element 4 and a low-pass filter 5, and an attenuator 7 that sets the amount of feedback from a partial feedback loop 6 of the output of the delay element 4. It is designed to be fed back to the input side via.

The adder 8 adds the L channel input signal L from the L channel input terminal 1 and the output signal of the low pass filter 5 and outputs the result to the L channel output terminal 10.

Similarly, the adder 9 adds the R channel input signal R from the R channel input terminal and the output signal of the low pass filter 5 and outputs the result to the R channel output terminal 11.

Next, the operation of the reverberation generating device shown in FIG. 1 will be explained. L applied to L channel input terminal 1
The channel input signal and the R channel input signal applied to the R channel input terminal 2 are added by an adder 3, and a (L+R) signal is output. The output signal of the adder 3 passes through a delay element 4 and further passes through a low-pass filter, and a (L+R) signal delayed by a certain time is output from the low-pass filter 5.

Also, a part of the output from the delay element 4 is transmitted to an attenuator 7.
The signal is fed back to the input side of the delay element 4 through a feedback loop 6 including . Then, the signal that has passed through this delay processing path is sent to the adder 8 as the L channel input signal L which is directly input from the L channel input 1.
and is output from the L channel output terminal 10.

Similarly, the R channel input signal R directly input from the R channel input terminal 2 and the signal that has passed through the delay processing path are added by the adder 9 and output from the R channel output terminal 11.

As a result, for example, if the delay time of the delay element 4 is T and the amount of attenuation of the attenuator 7 is α, a signal with reverberation as shown in FIG. 2 will be output.

Since the conventional reverberation generator is configured as described above, the amount of attenuation of the reverberation component contained in the output signal is also determined at regular time intervals, and the amount of attenuation is determined at regular intervals. It lacked naturalness in terms of signal attenuation level and direction of arrival of reflected sound, and had drawbacks such as the inability to reproduce natural reverberations.

This invention was made to eliminate the above-mentioned conventional drawbacks, and by improving the reverberation generation circuit and signal addition processing, etc., it generates natural reverberation and creates a three-dimensional sound field similar to the reverberation characteristics of a hall. The purpose of the present invention is to provide a natural sound field reproduction device that can create a natural sound field.

Embodiments of the natural sound field reproducing device of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing the configuration of one embodiment. In this Figure 3, the two channels are L channel and R channel.
I will describe it as a channel. Since the L channel and the R channel have the same configuration, the L channel will be described as a representative, and the explanation of the R channel will be omitted.

An L channel input signal is input to the L channel input terminal 21, and an R channel input signal is input to the R channel input terminal 22.

The L channel input signal input to the L channel input terminal 21 is applied to the low pass filter 23 and the adder 33, and similarly, the R channel input signal input to the R channel input terminal 22 is applied to the R channel input signal. It is adapted to be added to a low pass filter and adder 42.

In the L channel, the low pass filter 23
The output of is applied to a multi-tap output delay element 26. This multi-tap output delay element 26 generates outputs with different delay times, and the illustrated embodiment shows the case of five taps.

The output of the multi-tap output delay element 26 is applied to the input of the multi-tap output delay element 26 via feedback loops 27a to 27e, through attenuators 29a to 29e, and directly to each input terminal of the buffer circuits 28a to 28e. It's getting old.

Buffer circuits 28a to 28e constitute a buffer group 28, and each buffer circuit 28a to 2
The output of 8e is input to adders 31, 34, 37, and 40 through level adjusters 30a to 30e.

For each output of the level adjusters 30a to 30e,
Buffer circuits 28a to 28 with four different attenuation amounts
It controls the output of e and generates four different levels of output. That is, the level adjuster 30a has four coefficients α ₁ , β ₁ , γ ₁ , and δ ₁ , and the level adjuster 30b has four coefficients α ₂ , β ₂ , γ ₂ , and δ ₂ . The level adjuster 30c has α ₃ , β ₃ ,
The level adjuster 30d has four coefficients α ₃ , δ ₃ , and further has four coefficients α ₄ , β ₄ , γ ₄ , δ ₄ .
The level adjuster 30e has four coefficients α ₅ , β ₅ , γ ₅ , and δ ₅ .

Therefore, the level adjuster 30 composed of the level adjusters 30a to 30e has five levels in the L channel alone.
×4=20 outputs with different delay times and attenuation levels can be obtained, and the same is true for the R channel, resulting in a total of 40 outputs with different delay times and attenuation levels for both the L channel and R channel. is starting to occur.

Coefficient α ₁ of level adjusters 30a to 30e,
The level-adjusted signals of α ₂ , α ₃ , α ₄ , and α ₅ are added by an adder 31 and passed through a low-pass filter 3.
2 and then sent to an adder 33.

The coefficients β ₁ , β ₂ ,
The level-adjusted signals β ₃ , β ₄ , and β ₅ are added together in an adder 34, and then passed through a low-pass filter 3.
5 to the adder 36.

The coefficients γ ₁ , γ ₂ ,
The level-adjusted signals of γ ₃ , γ ₄ , and γ ₅ are added in an adder 37, and then passed through a low-pass filter 3.
8 and is sent to an adder 39.

Furthermore, the signals that have undergone level adjustment of attenuation amounts δ ₁ , δ ₂ , δ ₃ , δ ₄ , δ ₅ by the level adjusters 30a to 30e are added by an adder 40 and sent to an adder 42 through a low-pass filter 41. It's becoming like that.

Among the adders 33, 36, 39, and 42, the adder 33 receives the output of the low-pass filter 32, the output of the corresponding R-channel low-pass filter, and the L-channel input directly input from the L-channel input terminal 21. The signal L is added to the signal L and sent to the output terminal 24.

Similarly, the adder 36 is connected to the low pass filter 3
5 and the output of the corresponding R channel low-pass filter are added and outputted to the output terminal 43.

The adder 39 receives the output of the low-pass filter 38,
This is added to the output of the low-pass filter of the corresponding R channel and output to the output terminal 44.

Furthermore, the adder 42 adds the output of the low-pass filter 41, the output of the corresponding R channel low-pass filter, and the R channel input signal R input directly from the R channel input terminal 22, and outputs the sum to the output terminal 25. This is what is output.

Note that the reference numeral 100 indicates a signal processing path for the R channel, which includes a low-pass filter 23, a multi-tap output delay element 26, and a multi-tap output delay element 26 for the L channel.
Feedback loops 27a to 27e, buffer circuit 28a
~28e, attenuators 29a~29e, level adjusters 30a~30e, adders 31, 34, 37, 4
0 and low-pass filters 32, 35, 38, and 41.

Next, the operation of the natural sound field reproducing apparatus of the present invention configured as described above will be explained. First, L
The L channel input signal applied to channel input terminal 21 passes through low pass filter 23 and enters multi-tap output delay element 26 (eg, 5-tap BBD).

The output from this multi-tap output delay element 26 is multi-tap output delayed so that five outputs with different delay times are passed through feedback loops 27a to 27e and attenuators 29a to 29e each having a different amount of attenuation. It is fed back to the input terminal of element 26.

The five delayed signal groups obtained through this processing pass through buffer circuits 28a to 28e, respectively, to level adjusters 30a to 30a forming the level adjuster 30.
30e.

The coefficients of these level adjusters 30a to 30e are expressed as α ₁ , β ₁ , γ ₁ , δ ₁ , α ₂ , β ₂ , γ ₂ ,
δ ₂
..., adders 31, 34, 37, 40
The following signal appears. Here, the L channel input signal is assumed to be L.

The adder 31α output is α ₁ L _T1 + α ₂ L _T2 + α ₃ L _T3 + α ₄ L _T4 + α ₅ L _T5 + Sd (α, T
)= _N 〓 ⁿ⁼¹ αnL _T n+Sd (α, T) ...(1).

Further, the output of the adder 34 is _N 〓 ⁿ⁼¹ βnL _T n+Sd (β, T) (2).

The output of the adder 37 is _N 〓 ⁿ⁼¹ γnL _T n+Sd (γ, T) (3).

The output of the adder 40 is _N 〓 ⁿ⁼¹ δnL _T n+Sd (δ, T) (4).

Here, Sd is a group of signals generated by the feedback loop, N is the number of outputs of the multi-tap output delay element 26 (5 in this case), and T is the delay time.

Furthermore, the R channel is processed in exactly the same way as the L channel, and the following output is obtained. However, the dashed lines indicate that they correspond to each coefficient of the L channel level adjuster. _N 〓 ⁿ⁼¹ α′nR _T n+Sd (α′, T) ……(5) _N 〓 ⁿ⁼¹ β′nR _T n+Sd) (β′, T) ……(6) _N 〓 ⁿ⁼¹ γ′ nR _T n+Sd (γ′, T) …(7) _N 〓 ⁿ⁼¹ δ′nR _T n+Sd (δ′, T) …(8) The L channel shown by these equations (1) to (4) Among the reverberant signals, the reverberant signal of equation (1) and the R channel
The reverberation signal in equation (5) is directly added to the L channel input signal L applied to the L channel input terminal 21 in the adder 33, and a signal expressed in the following equation (9) is output to the output terminal 24. .

The output signal of equation (9) is output from the speaker _S1 in FIG. 4 (indicated as 109 in FIG. 4) through an amplifier (not shown).

L+ _N 〓 ⁿ⁼¹ αnL _T n+ _N 〓 ⁿ⁼¹ α′nR _T n+Sd(α,T)+Sd(α′,T)……(9) Also, the reverberation signal of the L channel shown in equation (2) and (6)
The reverberation signal of the R channel shown in the formula is added to the adder 36.
are added, and a signal expressed by the following equation (10) is output as the output signal 43.

The signal expressed by equation (10) is output from the speaker _S2 in FIG. 4 (indicated as 110 in FIG. 4) through an amplifier (not shown). _N 〓 ⁿ⁼¹ βnL _T n+ _N 〓 ⁿ⁼¹ β′nR _T n+Sd (β, T) Sd (β′, T) ...(10) Furthermore, the reverberation signal of the L channel shown in equation (3) and
The reverberation signal of the R channel shown in equation (7) is added to the adder 3.
9 and outputted to the output terminal 44 as shown in the following equation (11).

The signal expressed by equation (11) is output from the speaker _S3 in FIG. 4 (indicated as 111 in FIG. 4) through an amplifier (not shown). _N 〓 ⁿ⁼¹ γnL _T n+ _N 〓 〓 ⁿ⁼¹ γ′nR _T n+Sd(γ,T)+Sd(γ′,T)……(11
) Also, the reverberation signal of the L channel shown in equation (4) and (8)
The R channel reverberation signal shown by the equation and the R channel input signal R directly applied from the R channel input terminal 22 are added by the adder 42 and output to the output terminal 25 as shown by the following equation (12).

The signal expressed by equation (12) is output from the speaker _S4 in FIG. 4 (shown as 112 in FIG. 4) through an amplifier (not shown).

R+ _N 〓 ⁿ⁼¹ δnL _T n+ _N 〓 〓 ⁿ⁼¹ δ′nR _T n+Sd(δ, T)+Sd(δ′, T)……(12
) In the arrangement of the speakers S ₁ to _{S 4} shown in FIG. 4 that output such reverberant signals, speaker S ₁ is the L channel front speaker, and speaker S ₄ is the L channel front speaker.
is the R channel front speaker, and the speaker
When S ₂ is used as an L channel backspeaker and speaker S ₃ is used as an R channel backspeaker, for example, the coefficients in the level adjusters 30a to 30e are αn=1, βn=
0, γn=0, δn=0, the reverberation signal L _T n is the left channel front speaker S ₁
localize at the position.

In this way, by setting the coefficients of the level adjusters 30a to 30e, it becomes possible to localize the reverberant signal group in any direction, and as shown in FIG. It is possible to realize natural sound field reproduction in which a group of reverberant signals arrive from any direction.

Although the above embodiment describes the case of 4-channel reproduction, reproduction with any number of channels may be possible.In this case, it can be realized by changing the way of adding signal groups, and it can be effective as a natural reverberation device. Play.

As described above, according to the natural sound field reproducing device of the present invention, a signal group is generated by giving input signals for each channel a plurality of predetermined delay times and levels, and this signal group and each channel are directly input. Since the signal and the signal group having the predetermined delay time and level of the other channels are added together and output, signal groups with different delay times and attenuation levels can be generated, making it possible to reproduce a three-dimensional sound field. Further, by setting the coefficients of the level adjuster, the sound field can be localized in any direction, and therefore a three-dimensional sound field similar to the reverberation characteristics of a hall or the like can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional reverberation generation device, FIG. 2 is a diagram showing the time and level of the output signal of the reverberation generation device of FIG. 1, and FIG. 3 is an implementation of the natural sound field reproduction device of the present invention. FIG. 4 is a block diagram showing an example, and is a speaker arrangement diagram showing an example of sound field reproduction applied to the natural sound field reproduction device of the present invention. 21...L channel input terminal, 22...R channel input terminal, 24, 25, 43, 44...
Output terminal, 26...Multi-tap output delay element, 28
a~28e... Buffer circuit, 29a~29e...
...Attenuator, 30a-30e...Level adjuster, 3
1, 33, 34, 36, 37, 39, 40, 42
... Adder, 100 ... R channel signal processing system, S ₁ to _{S 4} ... Speaker.

Claims (1)

[Claims] 1. A first means for receiving an L channel signal, delaying and level controlling the L channel input signal at a plurality of predetermined delay times and attenuation levels, and outputting the L channel input signal as a plurality of delayed signals; , a plurality of level adjusters that perform level adjustment on each of the plurality of delayed signals obtained by the first means using a plurality of predetermined level coefficients and output the resultant as a plurality of delayed signal groups; a first addition means for adding predetermined delay signals from a predetermined level adjuster among each delay signal group from the adjuster and outputting a plurality of summed signals; a first means, a plurality of level adjusters, and a first summing means for the R channel signal having a similar configuration to the first summing means; a second addition means for adding and outputting one of the addition signals of the addition means, one of the addition signals of the first addition means of the R channel, and a direct input signal of the L channel; one of the addition signals of the first addition means which is different from the addition signal inputted to the second addition means; and one of the addition signals of the first addition means in the R channel which is different from the addition signal input to the second addition means; a third addition means for adding and outputting one of the addition signals different from the addition signal input to the means and a direct input signal of the R channel; one of the addition signals different from the addition signals inputted to the second and third addition means;
a fourth addition means for adding and outputting one of the addition signals of the first addition means in the R channel, which is different from the addition signals inputted to the second and third addition means; A natural sound field reproduction device.