JPS62283800A - Acoustic reproducing device - Google Patents

Abstract

PURPOSE:To obtain the same sound field as that in a theather even by inputting a normal sound signal by inserting an echo circuit into a channel signal line. CONSTITUTION:In the echo circuit 7, a mixer 71 mixes a first arriving sound signal with a sound signal that passes the delay time set by a delay circuit 73 through the delay circuit 73 and a gain adjustment circuit 74, and the 1st echo of the sound signal is attenuated by the gain adjustment circuit 74 compared with an original. Since a 2nd echo comes in the mixer 71 through a mixer 72, the delay circuit 73 and the gain adjustment circuit 74 after it enters another gain adjustment circuit 75, it is delayed hourly and considerably attenuated compared with the 1st signal. A 3rd and a fourth ones are further delayed and attenuated, and these actions are made more complicatedly, thereby adding a desired echo.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a sound reproduction device equipped with an echo circuit.

[Prior art]

Certain types of musical performances, such as symphonic performances, are generally held in large halls, and in these cases the musical sounds, in addition to reaching the ears of the listeners directly, also reach the ears of the audience after being reflected off the ceiling, walls, and other reflective surfaces of the hall. , reaching the listener's ears from various directions and via multiple routes. In the latter component, the amplitude, especially the high frequency component, decreases exponentially, and the phase shifts with respect to the sound source, causing a time difference.
This results in reverberant sound containing many echo (reverberation) components.

On the other hand, when playing the musical sounds recorded from the above-mentioned performance, there is no reverberation included in the sound, so in a normal living room or car, reverberation will not be noticeable to the ears due to the small size of the room. is normal.

[Purpose of the invention]

An object of the present invention is to provide a sound reproduction device that can obtain a sound field similar to that in a theater while inputting a normal audio signal.

[Structure of the invention]

To this end, the present invention provides an audio reproduction device that reproduces a channel signal as it is from the front speakers and also processes the channel signal and reproduces it from the rear speakers as a surround signal. I configured it by inserting the .

〔Example〕

Examples of the present invention will be described below. FIG. 1 is a diagram showing the circuit of the sound reproduction device. 1.1' is an input terminal into which the R channel audio signal and L channel audio signal are input, 2.2' is a buffer, 3.3' is a control a terminal 3a,
This is a delay circuit whose delay time can be adjusted by a control pulse applied to 3a'.

Further, 4 is an (L + R) addition circuit that adds the output signals from the delay circuit 3.3', 5.5' is a buffer, and 6.6
' is a delay circuit that delays the output signal from the buffer 5.5', and its delay time can be adjusted by control pulses applied to control terminals 6a, 6a'.

7.7' is an echo circuit, and one echo circuit 7 is
It consists of a mixer 71, 72, a delay circuit 73, and a gain adjustment circuit 74, 75 that sets the output level below the input level.The mixer 72 mixes (adds) the output signal from the delay circuit 6 and the signal from the gain adjustment circuit 75. , its output is sent to delay circuit 7
3, its output is level-adjusted by a gain adjustment circuit 74, and the output is mixed (added) with the output signal of the delay circuit 6 by a mixer 71 and output.
A part of the output of 4 is input to a gain adjustment circuit 75 and mixed again by a mixer 72.

Therefore, the gain of the gain adjustment circuits 74 and 75 is set to the terminal 74.
A desired reverberation can be added by adjusting the signal voltages applied to terminals 75a and 75a, and by adjusting the delay time of delay circuit 73 by pulses applied to terminal 73a. As this reverberation time interval, for example, Looms
~ several lll5 is preferable. Since the other echo circuit 7' has a similar configuration, similar components are given the same reference numerals with the suffix r'. In addition, the terminal 7 of the delay circuit 73, 73'
If the control pulses to 3a and 73a' are stopped, there will be no reverberation.

8 is a sound quality adjustment circuit that inputs the output signal from the echo circuit 7.7' and adjusts the frequency characteristics; for example, 10) (
Adjusted to cut components above Hz. Reference numeral 9 denotes an addition/subtraction circuit that subtracts and adds the two input signals output from the sound quality adjustment circuit 8 at an appropriate ratio, or outputs them as they are.

10 subtracts the output signal from the echo circuit 7.7' (
LR) subtraction circuit; 11 is a slow bass filter that extracts components of 7 KIIz or less from the output signal from the subtraction circuit 10; 12 is a noise removal circuit;

VRL to VR6 are linked variable resistors for volume adjustment, VRI is for the front speaker 21, VH2 is for the front R speaker 22, VH3 is for the front center speaker 23, and VH2 is for the rear center speaker 24.
VH5 is for the rear rear speaker 25, and VH6 is for the rear R speaker 26 (see Fig. 2).

In addition, the above-mentioned delay circuits 3.3', 6.6', 73.7
As for 3', it can be configured with a BBD (packet brigade device), but it can also be configured with a CCD (
It is also possible to use charge coupled devices). However, when using this COD, it is necessary to modulate the input signal with a high frequency, delay it with the COD, and then demodulate it into a low frequency component.

Now, the R and L channel audio signals applied to the input terminal 1.1' are delayed by the delay circuit 3.3', inputted to the variable resistors VRI and VR2, reproduced by the speakers 21.22, and added. The signals are added by the circuit 4, input to the variable resistor VR3, and reproduced by the speaker 23.

Therefore, if the delay times of the delay circuits 3 and 3' are made different,
For example, as shown by the symbol B in FIG.
1.12 (differences in the arrival time of audio can be compensated for). In this case, for example, the delay time of the delay circuit 3' that sends the output signal to the speaker 21 is It is sufficient to make the delay time longer than the delay time of
Regarding the reproduced portion from here, the arrival time of the L channel signal component is delayed, and the compensation for the shift in the listening position becomes more effective.

The delay circuits 6 and 6' at the rear stage are for the audio signals reproduced by the rear speakers 24 to 26, and by setting the delay time here, the surround sound from the rear can be adjusted. For example, if the listening position is shifted as described above, the delay circuit 3.3' in the preceding stage may be used to provide a difference in delay time, and the delay circuit 6.6' in the subsequent stage may not delay the signal. , front-stage delay circuit 3.3'
In this case, as long as the listening position is in the center between the front and rear, there will be no time difference between the sounds played by the front and rear L and R speakers. Does not occur.

However, if the same delay time is provided in the delay circuits 6 and 6' in the subsequent stage, in addition to the above-mentioned phase difference between It will be the same as Furthermore, if the delay times of the delay circuits 6 and 6' are made different, the audio reproduced from the rear speakers 24 to 26 will have a fairly complex phase difference and time difference with respect to the audio reproduced from the front speakers 21 to 23. It comes to have. In particular, with respect to surround components reproduced by the speaker 24, correction can be made when the listening position is shifted from the center.

In the echo circuit 7, the first arriving sound signal passes through a mixer 72, a delay circuit 73, and a gain adjustment circuit 74, and is mixed at the mixer 71 with the sound signal after the delay time set by the delay circuit 73 has elapsed. The first echo of the sound signal becomes an echo that is attenuated only by the gain adjustment circuit 74 compared to the original. The second echo enters another gain adjustment circuit 75 and then reaches the mixer 71 via the mixer 72, delay circuit 73, and gain adjustment circuit 74, so it is further delayed in time compared to the first signal. It is also greatly attenuated. The third and fourth shots will have a greater delay and attenuation. Since this action is performed in a complicated manner, it becomes possible to add a desired echo. Then, the delay time setting of the delay circuit 73 and the gain adjustment circuit 74.75
By appropriately setting the gain, it is possible to achieve a reverberant sound that matches the actual hall. The above also applies to the other echo circuit 7'.

The circuits from the subtraction circuit 10 to the noise removal circuit 12 process the LR signals. Here, the in-phase components of the L channel component and the R channel component of the output signal from the echo circuit 7.7' are canceled out, and in an actual hall, the treble component of the echoes from the walls etc. is largely attenuated. To match this, high-frequency components are filtered through a low-pass filter 1.
1 and the noise component removed by the noise removal circuit 12 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-reverberant sound obtained by mixing a plurality of sounds reflected from a sanctuary at the back of a hall or the like using multipath.

The sound quality adjustment circuit 8 attenuates the high-frequency components of the output signal from the echo circuit 7 , 7 ′, cuts off components of 10 KHz or higher, for example, and sends the signal to the addition/subtraction circuit 9 .

The two outputs of this addition/subtraction circuit 9 have αL−βR1αR.
A signal such as -βL is obtained by subtracting appropriate amounts of the signal components of both channels. α and β are coefficients, α≦1, β≦
It is 1. Therefore, when α==11 and β=O, L,
The R signal component is obtained separately, and when α=0 and β=1, signal components with inverted channels such as -L and -R are obtained separately.

Through the above rear speakers 24 to 26, the L channel sound and R channel sound from the front are reflected in the hall and converted into indirect sounds that have undergone various transformations in phase, time, level, path, and frequency. This is played back as a simulated sound, resulting in surround sound.

In addition, in the above, the echo circuit 7.7' can also be inserted at the position immediately after the delay circuit 3.3' or at the value immediately after the delay circuit 6.6', and in the former case, the echo circuit 7.7' The echo effect is applied not only to the sound played from the front speakers but also to the sound played from the front speakers.

〔Effect of the invention〕

As described above, according to the present invention, not only can echo be applied to the sound from the rear, but also the surround sound from the front can be echoed, making it possible to reproduce a sound field that is closer to that in a theater. Become.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a sound reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a layout diagram of speakers. ■, 1'... input terminal, 2.2'... bar 7,
3.3'...Previous stage delay circuit, 4...Addition circuit, 5
．． 5'... Buffer, 6.6'... Later stage delay circuit, 7.7'... Echo circuit, 8... Sound quality 8) 1 Adjustment circuit, 9... Addition/subtraction circuit, 10...・Subtraction circuit, 11・
...Low pass filter, 12...Noise removal circuit.

Claims (5)

[Claims] (1) In a sound reproduction device that reproduces a channel signal as it is from a front speaker and also processes the channel signal and reproduces it as a surround signal from a rear speaker, an echo circuit is inserted into the channel signal line. A sound reproduction device characterized by: (2) Claim 1 characterized in that the echo circuit is inserted in a line common to the channel signal reproduced by the front speaker and the channel signal reproduced by the rear speaker. The sound reproduction device described in Section 1. (3) A patent claim characterized in that the echo circuit is inserted only into the channel signal line reproduced by the rear speaker, so that echo is applied only to the sound reproduced from the rear speaker. The sound reproduction device according to item 1. (4) The echo circuit includes a delay means for delaying the input signal, a gain adjustment means for adjusting the gain of the signal delayed by the delay means, and a signal from the gain adjustment means mixed with a new signal and outputted. 2. The sound reproducing apparatus according to claim 1, further comprising a mixing means and another mixing means for mixing the signal from the gain adjustment means and the input signal to the delay means. (5) The sound reproduction device according to claim 4, wherein the echo circuit has another gain adjustment means between the signal from the gain adjustment means and the other mixing means. .