JPH01135222A - Sound field reproducing device - Google Patents

Abstract

PURPOSE:To reproduce an arbitrary sound field with a simple constitution by extracting the feature of the impulse response to be measured with a real time and multiplying and adding the impulse response with a music signal. CONSTITUTION:An impulse to execute the impulse response measurement is generated from a generator 1 and reproduced from a speaker 2 to a sound field. Next, the impulse response of the sound field is measured by a mike 3 and supplied to an integrator 4 and a memory 5 after amplification. The integrator 4 multiplies an input signal and sends an amplitude value for every prescribed time to the memory 5. The memory 5 supervises the impulse response for every integrating time, detects the time when the amplitude becomes maximum and stores the amplitude value corresponding to the value as a pair. These amplitude values are compared with a data transferring device 10, extracted in the larger sequence of the mere number of a delaying device and a multiplier in an FIR filter 6, each time of the pair of the amplitude value is transferred to the multiplier and the delaying device, overlapped to a music signal from a terminal 11 and outputted from a terminal 12. As the result, the sound field to be simulated is reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sound field reproducing device for reproducing realistic sound.

2. Description of the Related Art In recent years, realistic sound reproduction has been desired, and equipment capable of producing surround effects has been developed.

Conventionally, as a method for reproducing a realistic sound field, a method has been used in which the impulse response of a certain hall is measured, and the measured impulse response and the music signal are multiplied and summed (convolution operation).

FIG. 3 shows an impulse response of a certain hall and a conventional sound field reproduction device using this.

In Fig. 3, a is a measured impulse response, b is a schematic enlarged view of the time of the first and last impulse responses of a, and C is a convolution operation used as a sound field reproduction device. In the FIR filter, 14 is the input terminal,
16 is an output terminal, 3 Heno 161 to 166 are delay devices that delay by τ time, 171
175 is a multiplier, and 18 is an adder.

As shown in this figure, one delay device and one multiplier correspond to each measured impulse response, and the impulse response of the sound field is convolved with the music signal, resulting in the intended hall sound. The field is regenerated.

However, in the above configuration, if you want to faithfully reproduce a sound field with its impulse response, each value of the measured impulse response must be multiplied by a set of delay devices. However, in order to realize this, an enormous amount of hardware and high-speed multipliers and adders are required.

In view of the above drawbacks, the present invention thins out the impulse response of the measured sound field in real time and extracts the characteristics of the impulse response, thereby making it possible to reproduce the sound field using small-scale hardware and an ordinary multiplier-adder.

Means for Solving the Problems In order to achieve the above object, the present invention provides an impulse generating means for outputting an impulse, a speaker for outputting a signal,
A microphone for measuring the impulse response, an integrating means for integrating the signal, a storage means for storing a set of the time at which the impulse response is maximum and the integrated amplitude signal, an FIR filter for actually processing the signal, and an amplitude value. The configuration includes setting means for setting the time and amplitude values stored in the selection storage means in descending order of magnitude to the FIR filter.

Function The present invention extracts the characteristics of the impulse response measured by the above-described configuration in real time, and multiplies and adds the extracted impulse response with a music signal, thereby realizing and reproducing a sound field with a simple configuration. It is possible.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of a sound field reproduction device according to a first embodiment of the present invention.

6. - In Fig. 1, 1 is an impulse generator that generates impulses, 2 is a speaker that actually radiates the impulses into the sound field, 3 is a microphone for impulse response measurement, 9 is an amplifier that amplifies the input signal, 4 is an integrator that squares the input signal, integrates it within a certain fixed time, squares the result, and outputs it, and 6 is the integrated signal (amplitude value) output from integrator 4. A memory that monitors the impulse response within the time period integrated by the integrator 4 and stores two sets of times at which the maximum value of the impulse response exists; 6 is an FIR filter that convolves the impulse response with the input signal; 71 ~76
is a delay device that delays the input signal by a given time, 81 to 86 are multipliers that multiply the input signal by a given coefficient, and 13 is an adder that inputs and adds each output of the multipliers 81 to 86. The device 10 compares the stored amplitude values, and stores corresponding numbers of the memory 6 in the corresponding delay devices 71 to 76 and multipliers 81 to 86 of the FIR filter 6 in descending order of the amplitude values.
11 is an input terminal for inputting a signal 6 such as a music signal, and 12 is an output terminal for outputting a signal processed by the FIR filter 6. be. (t1 to t6 and A1 to A6 in the figure correspond to the values shown in FIG. 2.) The operation of the sound field reproduction device configured as above will be described below.

First, an impulse generator 1 generates an impulse for impulse response measurement in a hall or the like to be simulated, and this impulse is reproduced from a speaker 2 into a sound field.

Next, the impulse response of the sound field is measured by the microphone 3, and after being amplified by the amplifier 9 to an appropriate magnitude, the signal is input to the integrator 4 and the memory 5.

The integrator 4 first squares the input signal, integrates it at certain time intervals, squares the result, and outputs the value (amplitude value) to the memory 6. FIG. 2 shows the method of integration performed by this integrator 4. In Fig. 2, a is a schematic representation of the measured impulse response, b is the squared impulse response divided by a certain time interval T during which it is integrated, and Y is −7 b at t1 to 7. 〇 is the time at which the impulse response has the maximum value within the time interval T, and A1 to 80 are each 1
It shows the square value of the value integrated over time.

The memory 6 monitors the input measured impulse response within the same time as the time when it is integrated by the integrator 4, detects the time when the amplitude is maximum within that time, and stores that value and the time from the integrator 4. The output amplitude values are stored as a set. Next, the data transfer device 10 compares each amplitude value stored in the memory 5, and extracts the same number of delay devices 71 to 76 and multipliers 81 to 86 of the FIR filter 6 in ascending order. The times when
76. However, the time transferred to the delay devices is set in the delay devices 71 to 76 closer to the input terminal 11 in order of shortest time, and the value is a relative value from the shortest time.

Then, actually in the FIR filter 6, the input terminal 1
The extracted and set impulse response to the music signal input to the music signal input section 1 is outputted from the convolution output terminal 12, and by reproducing this in a normal room, the sound field to be simulated is reproduced.

Furthermore, by backing up the contents of the memory, it is possible to play the contents at a later time.

Note that the same effect can be obtained even if the integrator 4 directly integrates the input signal without multiplying it by two. Further, by changing the integration time T in the integrator 4 depending on the sound field to be reproduced, it is possible to change the effect of sound field reproduction.

Effects of the Invention As described above, the present invention measures the impulse response in a sound field to be reproduced, thins out the impulse response measured in real time, and extracts its characteristics. It is possible to reproduce the sound field.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a sound field reproducing device according to an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the same operation, and FIG. 3 is a conventional sound field reproducing device '9 FIG. 2 is a schematic diagram showing the configuration and operation of the FIG. 1... Impulse generator, 2... Speaker, 3... Microphone, 4... Integrator,
6...Memory, 6...FIR filter,
9...Amplifier, 10...Data transfer device, 11...Input terminal, 12...Output terminal, 13...Adder, 71-76...
Delay device, 81-86...multiplier. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (2)

[Claims] (1) An impulse generating means that generates an impulse, a speaker that actually outputs the impulse to the sound field, a microphone that measures the impulse response, and a signal that divides the measured impulse response into a certain time interval. an integrating means for integrating an amplitude value; a storage means for storing as a set a time at which the impulse response measured within the time interval integrated by the integrating means and the integrated amplitude signal; A FIR filter consisting of a delay device, a multiplier, and an adder is compared with the amplitude values stored in the storage means, and a number corresponding to the number of delay devices and multipliers of the FIR filter is stored in descending order of amplitude values. A sound field reproducing device comprising setting means for setting the time and amplitude values of the FIR filter as the time and coefficients of the delay device and the multiplier of the FIR filter. (2) The sound field reproducing device according to claim 1, wherein the integrating means squares the input signal and then integrates the signal, squares the integrated signal, and outputs the squared signal.