JPS6060072B2 - Reverberation adding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reverberation adding device such as a stereo device.

In general, a reverberation adding device used in a stereo system etc. has a configuration as shown in FIG. 3 is input to an attenuator 9, and the delayed signal 3 passes through an attenuator 8 and is fed back to an adder 5.

Then, the direct sound signal 2 and the delayed signal 4 that has passed through the attenuator 9 are added together by an adder 6, and an output signal 10 with added reverberation is obtained. In such a reverberation adding device, the present invention calculates the autocorrelation function of the input signal based on the well-known fact that the physical characteristics of the sound source signal can be quantified by the autocorrelation function, and calculates the autocorrelation function at a certain delay time. The optimum reverberation effect corresponding to the input signal is obtained by changing the delay time of the delay circuit of the circuit for obtaining the reverberated sound in accordance with the magnitude of the correlation coefficient.

In general, the autocorrelation function of a sound source changes depending on the spectral components contained in the sound source, the periodicity of the sound source, the sampling frequency of the measurement system, the averaging time, etc., and shows a tendency as shown in FIG.

Then, find the autocorrelation function at a certain delay time Ti, and if the correlation with the original signal (T = 0) is high, the original signal is sustained by that amount and reverberation is added, and if the correlation is low, the original signal is Reducing the reverberation is effective as a reverberant sound effect, and this was confirmed in psychological experiments.

There is also a report that the autocorrelation function of the sound source is related to the delay time of the primary reflected sound in the sound field and the "preference" in subjective sound field evaluation. In the present invention, as shown in FIG. 3, the autocorrelation coefficient calculation circuit 11 calculates the autocorrelation coefficient of the input signal 1, and the delay time TO of the delay circuit 7 is calculated according to the magnitude of the autocorrelation coefficient calculation circuit 11. It is something that can change.

12 is a control signal voltage during the delay time.

An example of the autocorrelation coefficient calculation circuit 11 is shown in FIG.
7 is multiplied by the multiplier 13 and averaged by the averaging circuit 15.

Further, FIG. 4 shows a case where a plurality of delay times are required due to the characteristics of the input signal 1, and a plurality of delay circuits 14, multipliers 13, and averaging circuits 15 are each provided. The magnitude of the autocorrelation coefficient of the input signal obtained in this way is calculated by the calculation circuit 1.
6, it is converted into a delay time control signal voltage 12. This arithmetic circuit 16 may be configured with a peak value hold circuit, an average value calculation circuit, a weighting circuit, or the like. Also, the average circuit 15
The time constants T,, T2, . . . , Tn are the characteristics of the input signal 1 and the τ1, τ2, . determined by the value of Although FIG. 4 shows an analog example as an example of the autocorrelation coefficient calculation circuit 11,
In addition, a unipolar autocorrelation coefficient calculation circuit in which only one of the direct sound signal 2 and the delayed signal 17 is made into a zero-crossing wave, a bipolar autocorrelation coefficient calculation circuit in which both are made into zero-crossing waves, and a digital computer were used. It can also be realized with a circuit.

FIG. 5 shows an example of the relationship between the magnitude of the autocorrelation coefficient of the sound source and the delay time of the reverberation addition device in the reverberation addition device of the present invention.

As described above, when the reverberation adding device of the present invention is used to add reverberation to an audio device such as a stereo device, a large amount of reverberation is produced where the autocorrelation coefficient of the input signal is large, and a large amount of reverberation is produced where the autocorrelation coefficient is small. A small amount of reverberation can be obtained, and it is possible to obtain an acoustic effect that is more comfortable for both the person singing and the person listening than a constant amount of reverberation.

Brief Description of the Drawings Fig. 1 is a block circuit diagram of a conventional reverberation adding device, Fig. 2 is a diagram showing an example of an autocorrelation function of a sound source, and Fig. 3 is a block diagram of a reverberation adding device according to an embodiment of the present invention. 4 is a block circuit diagram showing an example of the autocorrelation coefficient calculation circuit of the same device, and FIG. 5 is a relationship between the magnitude of the autocorrelation coefficient of the input signal and the delay time of the reverberation adding device in the same device. It is a figure showing an example.

1... Input signal, 2... Direct sound signal, 3, 4...
・Delay signal, 5, 6...adder, 7...delay circuit,
8, 9... Attenuator, 10... Output signal, 11...
Autocorrelation coefficient calculation circuit.

Claims (1)

[Claims] 1. In a reverberation adding device that forms a reverberated sound by adding an input signal and a signal obtained by feeding back a delayed signal obtained by delaying this input signal, an autocorrelation function of the input signal is calculated, and a certain delay A reverberation adding device characterized by changing the delay time of a delay circuit in accordance with the magnitude of an autocorrelation coefficient in time.