JPH0748920B2 - Sound reproduction device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sound reproducing device having an echo circuit.

[Prior art]

Some types of musical performances, such as symphonic performances, are generally performed in large halls, where the musical sound in such cases reaches the listener's ears directly, as well as after being reflected on the ceiling, walls and other reflective surfaces of the hall. Reach the listener's ear in multiple ways from different directions. In the latter component, the amplitude, especially the high frequency component, decreases exponentially, and there is a phase difference with respect to the sound source, resulting in a time difference.
Reverberant sound that contains many echo (reverberation) components.

On the other hand, when replaying the musical sounds recorded from the above performances, reverberations are not included in them, so there is no reverberation that is audible to the ear due to their smallness in a normal room or car. Is normal.

[Object of the Invention]

It is an object of the present invention to provide a sound reproducing device capable of obtaining a sound field similar to that in a theater while inputting a normal audio signal.

[Structure of Invention]

To this end, the present invention reproduces independent R channel signals and L channel signals from the front R speaker and front L speaker, respectively, and processes both channel signals from the rear R speaker and rear L speaker. In a sound reproducing device adapted to reproduce, a delay circuit for delaying the two channel signals by the same or different time, an independent R echo circuit for inputting each of the delayed two channel signals and L
Echo circuit and independent R obtained by both echo circuits
Adjustment circuit for independently controlling the sound quality of each of the echo signals for L and the echo signal for L, and the echo signal for R multiplied by α (≦ 1) by processing both echo signals output from the voice adjustment circuit And the difference (αR-βL) between the L echo signal multiplied by β (≦ 1) is sent to the rear R speaker, and α
A circuit for sending a difference (αL-βR) between the multiplied L echo signal and the β multiplied R echo signal to the rear L speaker is configured.

〔Example〕

Examples of the present invention will be described below. FIG. 1 is a diagram showing a circuit of the sound reproducing apparatus. 1, 1'is an input terminal for inputting an R channel audio signal and L channel audio signal, 2 and 2'is a buffer, 3 and 3'is a control terminal 3a, 3
This is a delay circuit in which the delay time can be adjusted by the control pulse applied to a '.

Reference numeral 4 is an (L + R) adder circuit for adding the output signals from the delay circuits 3 and 3 ', 5 and 5'are buffers, and 6 and 6'are delay circuits for delaying the output signals from the buffers 5 and 5'. The delay time can be adjusted by the control pulse applied to the control terminals 6a and 6a '.

7, 7'is an echo circuit, and one echo circuit 7 is
The mixers 71 and 72, the delay circuit 73, and the gain adjustment circuits 74 and 75 that set the output level to the input level or lower are mixed, and the output signal from the delay circuit 6 and the signal from the gain adjustment circuit 75 are mixed (added) by the mixer 72. The output is delayed by the delay circuit 73, the output is level-adjusted by the gain adjusting circuit 74, and the output is mixed (added) with the output signal of the delay circuit 6 by the mixer 71 and output. A part of the output of 74 is input to the gain adjusting circuit 75 and mixed again in the mixer 72.

Therefore, the gains of the gain adjustment circuits 74 and 75 are set to the terminals 74a and 75a.
A desired reverberation can be added by adjusting the signal voltage applied to the input terminal and the delay time of the delay circuit 73 by adjusting the pulse applied to the terminal 73a. The reverberation time interval is preferably about 100 ms to several ms. Since the other echo circuit 7'has a similar structure, the same reference numeral is attached to the same component. It should be noted that if the control pulse to the terminals 73a and 73 'of the delay circuits 73 and 73' is stopped, no reverberation is produced.

Reference numeral 8 is a sound quality adjusting circuit which receives the output signals from the echo circuits 7 and 7'and adjusts the frequency characteristic, and is adjusted so as to cut components of 10 KHz or more, for example. Reference numeral 9 subtracts two input signals output from the sound quality adjustment circuit 8 at an appropriate ratio.
It is an adder / subtractor circuit that adds or outputs as it is.

Reference numeral 10 subtracts the output signals from the echo circuits 7 and 7 '(L-
R) Subtraction circuit, 11 is 7 from the output signal from the subtraction circuit 10.
A low-pass filter for extracting components below KHz, and 12 is a noise removing circuit.

VR1 to VR6 are variable resistors for interlocking volume adjustment.
Is for the front L speaker 21, VR2 is for the front R speaker 22, VR3 is for the front center speaker 23, VR4
Is for the rear center speaker 24, VR5 is for the rear L speaker 25, and VR6 is for the rear R speaker 26 (see FIG. 2).

The delay circuits 3, 3 ', 6, 6', 73, 73 'described above are used.
For the above, this can be configured with a BBD (bucket brigade device), but it is also possible to use a CCD (charge coupled device). However, when this CCD is used, it is necessary to modulate the input signal with a high frequency, delay it with the CCD, and then demodulate it into a low frequency component.

The R and L channel audio signals applied to the input terminals 1 and 1'are delayed by the delay circuits 3 and 3 ', and the variable resistance VR
1, is input to VR2 and reproduced by the speakers 21 and 22, and is added by the adder circuit 4 and input to the variable resistor VR3.
Will be played.

Therefore, if the delay times of the delay circuits 3 and 3'are made different,
For example, when the listening position is deviated from the center A on the bisector passing through the middle of the speakers 21 and 22 as shown by the symbol B in FIG. 2, the distances 1 and 12 from the speakers 21 and 22 are Differences in the arrival times of voices based on the differences can be compensated. In this case, for example, the delay time of the delay circuit 3 ′ that outputs the output signal to the speaker 21 may be set longer than the delay time of the other delay circuit 3. At this time, the sound from the speaker 23 at the center is an L + R signal, and the arrival time of the signal component of the L channel is delayed for these reproduced components as well, so that the deviation of the listening position is more effectively compensated. .

The delay circuits 6 and 6'in the rear stage are for the audio signals reproduced by the rear speakers 24 to 26, and the surround sound from the rear surface can be adjusted by the delay time setting here. For example, when the listening position is deviated as described above, a delay time is provided by the delay circuits 3 and 3'in the preceding stage, and signals are not delayed in the delay circuits 6 and 6'in the subsequent stage. The time difference between L and R is adjusted only by the delay circuits 3 and 3'in the front stage. In this case, as long as the listening position is at the center between the front and the rear, the front and rear L speakers and the R speaker There is no time difference for the sound played in.

However, when the same delay time is provided in the delay circuits 6 and 6'in the subsequent stage, in addition to the phase difference between L and R described above, a time difference between the front and the rear also occurs, so that the listening in the hall is not possible. Will be similar to. Further, when the delay times of the delay circuits 6 and 6'are made different, the sound reproduced from the rear speakers 24 to 26 is composed of the sound reproduced from the front speakers 21 to 23 and a complicated phase difference or There will be a time difference. In particular, the surround component reproduced by the speaker 24 can be corrected when the listening position deviates from the center.

In the echo circuit 7, the first incoming sound signal passes through the mixer 72, the delay circuit 73, and the gain adjusting circuit 74, and then to the mixer.
In 71, the sound signal after the delay time set by the delay circuit 73 is mixed, and thus the first echo of the sound signal becomes an echo which is attenuated only in the gain adjusting circuit 74 as compared with the original echo. The second echo reaches the mixer 71 via the mixer 72, the delay circuit 73, and the gain adjustment circuit 74 after entering the other gain adjustment circuit 75, so that it is further delayed in time compared to the first echo signal. It is also greatly attenuated. If the third and fourth shots are made, the delay and the attenuation become larger. Since this action is performed in a complicated manner, a desired echo can be added. Then, by appropriately setting the delay time of the delay circuit 73 and the gain settings of the gain adjusting circuits 74 and 75, it is possible to realize the reverberant sound that matches the actual hall. The above also applies to the other echo circuit 7 '.

The circuit from the subtraction circuit 10 to the noise removal circuit 12 is L-
Processing R signal. Here, the echo circuit 7,
Since the in-phase components of the L channel component and the R channel component of the output signal from 7'are canceled out, and in the actual hall, the treble component of the echo sound from the wall is greatly reduced,
Correspondingly, the high-frequency component is cut by the low-pass filter 11 and the noise component is removed by the noise removing circuit 12, and the component is reproduced from the rear center speaker 24. Therefore, a complex reverberant sound is reproduced from the rear center speaker 24, and this is a pseudo sound to the reverberant sound obtained by mixing a plurality of sounds reflected by a back wall in a hall or the like with multipath.

The sound quality adjusting circuit 8 attenuates the high frequency components of the output signals from the echo circuits 7 and 7 ′, cuts the components of 10 kHz or higher, for example, and sends them to the adder / subtractor circuit 9. 2 of this adder / subtractor circuit 9
At the respective outputs, signals obtained by subtracting appropriate amounts of the signal components of both channels, such as αL-βR and αR-βL, are obtained.
α and β are coefficients, and α ≦ 1 and β ≦ 1. Therefore,
When α = 1 and β = 0, the L and R signal components are obtained separately, and when α = 0 and β = 1, the signal components with inverted channels such as −L and −R are obtained. Obtained separately.

With the above-mentioned rear speakers 24 to 26, the L channel sound and the R channel sound from the front are reflected in the hall to become indirect sounds which are variously modified in terms of phase, time, level, path and frequency. It is played as a pseudo sound and becomes a surround sound.

〔The invention's effect〕

From the above, according to the present invention, it is possible to apply an echo to the sound from the rear and to exert the surround effect, and it is possible to arbitrarily set the content of the echo over a wide range, and depending on the case in the theater. It becomes possible to perform near sound field reproduction.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a sound reproducing device according to an embodiment of the present invention, and FIG. 2 is a layout diagram of speakers. 1, 1 '... input terminal, 2, 2' ... buffer, 3,
3 '... delay circuit in the previous stage, 4 ... addition circuit, 5, 5' ...
... buffer, 6, 6 '... delay circuit in the latter stage, 7, 7' ...
… Echo circuit, 8 …… Sound quality adjustment circuit, 9 …… Addition / subtraction circuit, 10 …… Subtraction circuit, 11 …… Low-pass filter, 12 ……
Noise removal circuit.

Claims (1)

[Claims] 1. An independent R channel signal and L channel signal are reproduced from a front R speaker and a front L speaker, respectively, and both channel signals are processed and reproduced from a rear R speaker and a rear L speaker. In the sound reproducing device as described above, a delay circuit for delaying the both channel signals by the same or different time, an independent R echo circuit for inputting each of the delayed both channel signals and L
Echo circuit and independent R obtained by both echo circuits
Adjustment circuit for independently controlling the sound quality of each of the echo signal for L and the echo signal for L, and the echo signal for R multiplied by α (≦ 1) by processing both echo signals output from the audio adjustment circuit And the difference (αR-βL) between the L echo signal multiplied by β (≦ 1) is sent to the rear R speaker, and α
A sound reproducing device, comprising: a circuit for sending out a difference (αL-βR) between the multiplied L echo signal and the β multiplied R echo signal to the rear L speaker.