JPH06261389A - Method and device for collecting sound with super high sensitivity - Google Patents

Abstract

PURPOSE:To remarkably improve the sensitivity of a microphone and suppress the deterioration of the frequency characteristic due to the high sensitivity processing. CONSTITUTION:The device is provided with microphone elements 1-30, band-pass filters 31-60, and adder 61. The resonance frequency of the mechanical system of the microphone elements 1-30 are set at 1/3 octaves. The output 1a-30a of the microphone elements 1-30 are passed through the band-pass filters 31-60, then added by the adder 61, and finally the output 62 is obtained. The band-pass filters 31-60 include the resonance frequency of the microphone elements 1-30 in the pass band, smoothing the frequency characteristic after the addition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high-sensitivity sound collecting method and apparatus which are improvements over the conventional sound collecting method using a single microphone.

[0002]

2. Description of the Related Art Conventionally, in order to increase the sensitivity of a microphone, (1) the size of a vibrating membrane has been increased and (2) the noise of a microphone amplifier has been reduced.

[0003]

However, the high sensitivity achieved by the conventional technique is about several dB at most, and does not significantly exceed the minimum audible limit of human beings. The reason is that, since the conventional technique uses a single microphone, it is theoretically difficult to achieve high sensitivity and high bandwidth at the same time.

Therefore, an object of the present invention is to provide an ultra-sensitive sound collecting method and device which combine a large number of sound collecting elements to achieve both high sensitivity and high band.

[0005]

In order to achieve the above object, an ultra-high-sensitivity sound collecting method according to the present invention has a plurality of electroacoustic conversions each having a sharp resonance characteristic for each specific frequency deviated by a slight frequency. By using elements, the output signals of the respective electroacoustic conversion elements are added in parallel to obtain a flat frequency characteristic.

Here, when adding the output signals of the electroacoustic conversion elements in parallel, it is preferable to add the signals obtained from the bandpass filter connected to the subsequent stage of each electroacoustic conversion element.

Further, the super-sensitive sound pickup device according to the present invention is
A flat frequency characteristic is obtained by including a plurality of electroacoustic conversion means each having a sharp resonance characteristic for each specific frequency deviated by a slight frequency and an addition means for adding output signals of the plurality of electroacoustic conversion means. Is.

Here, in addition to the above, it is preferable that a bandpass filter is connected to each of the latter stages of the plurality of electroacoustic conversion means.

[0009]

According to the present invention, in order to convert the vibration of air into an electric signal with an extremely high sensitivity, a large number of sound collecting elements (microphones) having different resonance frequencies are combined to achieve both an extremely high sensitivity and a flat frequency characteristic. It was made possible. That is, in the present invention, a plurality of electroacoustic transducers having sharp resonance characteristics are used, and their center frequencies are slightly changed and coupled.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 shows a system diagram of an ultra-sensitive sound pickup device to which the present invention is applied. The embodiment shown in the figure includes microphone elements 1 to 30, bandpass filters 31 to 60, and an adder 61. The resonance frequency of the mechanical system of each microphone element is set at 1/3 octave intervals. Each of the microphone elements 1 to 30 performs resistance control for flattening the frequency characteristic, which is performed by an ordinary microphone, to a minimum.

As a result, the output 1a of each microphone element
˜30a has a very high voltage at the resonance frequency, instead of having a non-flat frequency characteristic.

The outputs 1a to 30a of the microphone elements are passed through the bandpass filters 31 to 60 and then added by the adder 61 to form a final output 62.

The band pass filters 31 to 60 include the resonance frequency of the microphone element in the pass band thereof and flatten the frequency characteristic after addition. The final low output 62 not only has a high voltage, but is flat over a wide band.

In the embodiment shown in FIG. 1,
The number of microphone elements is 30 and the resonance frequency interval is 1/3 octave, but of course, this value can be arbitrarily designed.

Next, the operation of this embodiment will be described with reference to FIG. 2 showing the characteristics of each microphone shown in FIG. The characteristic of the original electrodynamic microphone is a resonance type as shown in A. In a normal microphone, an acoustic resistance is provided between the diaphragm and the rear chamber to suppress resonance, and the frequency characteristic is flattened like the characteristic B. However, this results in sacrificing microphone sensitivity and adding noise D in the preamplifier.
The difference between and cannot be increased.

On the other hand, in the present embodiment, the acoustic resistance is made as small as possible, and the bandpass filter is inserted in the output to have the characteristic shown in C by itself. In this case, a single unit has an extremely narrow frequency band, but a wide band can be covered by combining a plurality of microphones having different resonance frequencies.

FIG. 3 shows that a flat frequency characteristic E is obtained by combining a plurality of microphone outputs having different resonance frequencies.

[0019]

By implementing the present invention, the sensitivity of the microphone is significantly improved as compared with the conventional one, and it is possible to suppress the deterioration of the frequency characteristic due to the higher sensitivity.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention using a plurality of microphones.

FIG. 2 is a frequency characteristic diagram for explaining the operation of the present embodiment.

FIG. 3 is a frequency characteristic diagram for explaining the operation of the present embodiment.

[Explanation of symbols]

 1 to 30 microphone 31 to 60 band pass filter 61 adder

Claims (4)

[Claims] 1. A plurality of electroacoustic transducers each having a sharp resonance characteristic for each specific frequency deviated by a slight frequency are used, and output signals of the respective electroacoustic transducers are added in parallel to obtain a flat An ultra-sensitive sound pickup method characterized by obtaining frequency characteristics. 2. The method according to claim 1, wherein when the output signals of the electroacoustic conversion elements are added in parallel, the signals obtained from the bandpass filters connected to the subsequent stages of the electroacoustic conversion elements are added. Characteristic super-sensitive sound pickup method. 3. A flat plane comprising: a plurality of electroacoustic conversion means each having a sharp resonance characteristic for each specific frequency deviated by a slight frequency; and an addition means for adding output signals of the plurality of electroacoustic conversion means. Ultra-sensitive sound pickup device characterized by obtaining frequency characteristics. 4. The ultra-high sensitivity sound collecting device according to claim 3, further comprising a bandpass filter connected to each of the subsequent stages of the plurality of electroacoustic converting means.