JPS5843959B2 - Binaural signal recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pinaural signal recording device, in which a plurality of microphones having directivity in a specific direction are arranged close to each other in different directions relative to a sound source to form one microphone group, By arranging this group of microphones in pairs at intervals that allow recording of pinaural signals, the directional characteristics are virtually the same as those of omnidirectional microphones, and can be used for all frequencies in the audio band. An object of the present invention is to provide a recording device capable of obtaining an even pinaural signal.

Conventionally, the first method for recording pinaural signals is
Tummy head 1 with auricle as shown in figure or figure 2
Alternatively, the left and right signals R can be obtained by microphones 2a and 2b attached to the dummy head 1' without pinnae.
Alternatively, as shown in FIG. 3, left and right signals R were obtained by microphones 23' and 2b' placed apart from each other by an acoustic center distance d between the left and right ears.

These microphones are generally omnidirectional condenser microphones, but they are not omnidirectional at all frequencies; for example, as shown in Figure 4, they are almost omnidirectional at low frequencies (curve I). But high frequency (curve ■)
The directivity is remarkable, and there is large unevenness in the frequency range of the audio band.

For this reason, even if the signals obtained by conventional pinaural signal recording devices equipped with these microphones are played back, it cannot be said that the sound field at the time of recording is reproduced, the sense of presence is poor, and the S/N ratio is low. There were some drawbacks such as poor performance.

On the other hand, it is possible to reduce the diameter of the microphone's diaphragm in order to make it nearly omnidirectional;
There is a limit to this because of the deterioration of the ratio.

The present invention eliminates the above-mentioned drawbacks, and one embodiment thereof will be described with reference to FIG. 5 and subsequent figures.

FIG. 5 shows a principle diagram (only the right ear portion) of one embodiment of the pinaural signal recording device according to the present invention.

As shown in the figure, five unidirectional microphones 33 to 3e are arranged close to each other at different angles with respect to the sound source direction (arrow direction) to form one microphone group. When configured, the overall directional characteristic is directional in all directions, and if the signals from the microphones 3a to 3e are appropriately combined and calculated in the matrix circuits 4a and 4b, it becomes substantially omnidirectional. signals R, RB, and RF can be obtained.

Therefore, according to the device of the present invention, the directivity does not become particularly marked for a certain frequency as in the past, and there is no unevenness for frequencies in the audio band, and a high SN ratio can be achieved. I can get a signal.

In addition, by placing the microphones close together in this way, there is no phase difference between the signals recorded by each microphone, unlike when the microphones are placed apart, and when the signals from these microphones are combined, Unevenness in the frequency characteristics due to this phase difference does not occur, and a flat frequency characteristic can be obtained.

However, as shown in FIG. 5, it is difficult to attach many microphones to the dummy head, so in reality, as shown in FIG. Unidirectional microphones 6a, 6b and 6
c and 6d are respectively attached in the direction of the sound source (in the direction of the arrow) and in the opposite direction.

As shown in Fig. 1, the directional characteristics of the microphone group obtained by combining the microphones 6a and 6b (6c and 6d) arranged in this way form a pattern that mutually compensates for the low response parts of each microphone. , indicating a nearly omnidirectional pattern.

Signals LF, LB, RF, and RB from microphones 6a, 6b, 6c, and 5a are taken out as four-channel signals to output terminals 7a, γb, and 7c, 7d, respectively.

The signals LB, LF, RB, R extracted in this way
F is supplied to headphones (not shown) or reproduced through a speaker via a processor.

As is clear from FIG. 7, the combination of these signals LP, LB, RF, and RB, respectively, is substantially the same as the signal extracted by a substantially omnidirectional microphone for all frequencies.

Also, if the signals from the microphones 6a, 6b and 5c, 5d are taken out together to the output terminals 8a, 8b,
2 channel signal.

It is possible to obtain R.

As shown in FIG. 8, unidirectional microphones 6a, 6b, 5c, and 6ci were placed at a distance d between the acoustic centers of the left and right ears in the direction of the sound source and in the opposite direction, respectively, without using a dummy head. However, the same signal as above can be obtained.

FIG. 9 shows a schematic diagram of another embodiment of the device according to the invention.

In the figure, a unidirectional microphone 5a. 6c is attached to the left and right ears of the dummy head 5, respectively, at an angle θ with respect to the sound source direction, and the unidirectional microphones 6b and 6d are attached to the left and right ears, respectively, in a direction opposite to the sound source direction. They are installed offset by an angle ψ.

If the signals from the pair of microphone groups constituted by these microphones 6a to 6d are extracted by the method shown in FIG. 6, it is possible to obtain signals with uniform directivity as in the above embodiment.

Note that the angle formed by the two micros a, 6b, 6c, and 6d corresponding to one ear is approximately 1800 degrees, but even if the angles θ and ψ are shifted, it is permissible within a range that does not substantially cause uneven directivity. .

Moreover, as shown in FIG. 10, a unidirectional microphone 6a is used without using a dummy head.

Even if 6b, 5c, and 6d are arranged at an angle as shown in FIG. 9 and separated by a distance d, the same signal as above can be obtained.

FIGS. 11A and 11B show schematic diagrams of still another embodiment of the apparatus of the present invention.

In the figure, reference numerals 9a and 9b are unidirectional microphones called M (Mitsudo) microphones, which are attached to the left and right ears of a dummy head 5' with auricles facing toward the sound source.

Reference numerals 10a and 10b are bidirectional microphones called S (side) microphones, which are mounted on the left and right ears of the dummy head 5' at an angle of 900 degrees with respect to the direction of the sound source.

Microphones 9a and 103 (9b
The directional characteristics of the microphone group combining 10b and 10b show a pattern with some directivity in the gx+g2 direction, as shown by the broken line in FIG. 12, and a substantially omnidirectional pattern.

Signals taken out from the microphones 9a and 10a are supplied to a matrix circuit 11a consisting of a differential transformer, etc.
Here, it is converted into a sum signal M+8 and a difference signal MS to become signals LP and LB for the quad biphonic, and taken out to output terminals 12a and 12b.

Similarly, signals from the microphones 9b and 10b are converted into signals RF and RB in the matrix circuit 11b, and taken out to output terminals 12c and 12d.

These 4 channel signals LP. As is clear from FIG. 12, the combination of LB, RF, and RB is substantially the same as the signal extracted by a substantially omnidirectional microphone for all frequencies.

In addition, in FIG. 11, a bidirectional microphone 10a.

M+5-M by replacing 10b with a unidirectional microphone
-8, two-channel signals of the husband signal LR can be taken out from the terminals 13a and 13b.

Also, in FIG. 11, a unidirectional microphone 9a.

9b and the bidirectional microphones 10a and 10b are mounted at appropriate angles with respect to the direction of the sound source, the directivity direction g19g2 shown in FIG. 12 can be appropriately selected.

Furthermore, a microphone 9'a as shown in FIG.

Even if 9b 10a 10b is attached to a dummy head without an auricle, the same signal as above can be obtained, and as shown in FIG. A signal similar to that described above can be obtained even if they are arranged at an angle as shown in FIG. 11 and separated by a distance d.

In addition, in the above embodiment, the configuration is such that two channel or four channel signals are obtained using two microphones on the left and right sides, but the configuration is not limited to the above embodiment, and it is possible to obtain signals from several microphones. A multi-channel signal may be obtained by mixing as appropriate.

As described above, the pinaural signal recording device according to the present invention includes a plurality of microphones having directivity in a specific direction, each arranged in a different direction relative to a sound source and close to each other to form one microphone group. In principle, for example, unidirectional microphones can be placed on the left and right, facing in all directions relative to the sound source. , and its directional characteristics are directional in all directions, so if you combine them, the characteristics are essentially the same as those of an omnidirectional microphone. Because of this arrangement, it is possible to obtain an even signal for all frequencies in the audio band, and unlike conventional devices that use only omnidirectional microphones, there is no noticeable distortion at certain frequencies. It is possible to obtain reproduced sound with a richer sense of reality than the conventional example, and to obtain high-quality reproduced sound with a high SN ratio.For example, in the case of 4 channels, Compared to simply using a combination of omnidirectional microphones, it is possible to achieve more reliable separation between the front and rear, and furthermore, by appropriately shifting the relative angles of the microphones composing each microphone group to the sound source, it is possible to achieve some directivity as appropriate. It has the characteristics of being able to obtain a unique pinaural signal.

[Brief explanation of the drawing]

Figures 1 to 3 are schematic diagrams of each side of a conventional pinaural signal recording device, Figure 4 is a directional characteristic diagram of the microphone of the device shown in Figures 1 to 3, and Figure 5 is the present invention. Diagram 6 for explaining the principle of the pinaural signal recording device
The figure is a schematic diagram of one embodiment of the pinaural signal recording device according to the present invention, FIG. 1 is a directional characteristic diagram of the microphone of the device shown in FIG. 6, and FIGS. FIG. 12 is a schematic view of another embodiment of the present invention. FIG. 12 is a directional characteristic diagram of the microphone of the device shown in FIGS. 11A and 11H. FIG. 13 is a schematic diagram of still another embodiment of the device of the present invention. 3a to 3e, 6a to 6d, 9a, 9b...unidirectional microphone, 4a, 4b, Ila, 11b...
...Matrix circuit, 5, 5'...Dummy head, 7a-7d, 8a, 8b, 12a-12
d, 13a. 13b...Output terminal, 10a, 10b...
・Bidirectional microphone.

Claims (1)

[Claims] 1. A plurality of microphones having directivity in a specific direction are placed close to each other in different directions relative to the sound source to form one microphone group, and this microphone group is paired at intervals that allow recording of pinaural signals. A pinaural signal recording device characterized by being arranged in the shape of a hole.