JPS5967797A - Microphone device - Google Patents

Abstract

PURPOSE:To increase the sensitivity of a microphone to sound in the direction desired to be listened to and to reduce the microphone sensitivity to the sound in other direction by connecting the plural microphones so that a synthesized output is minimized to the sound in the orthogonal direction to the array direction of the microphones. CONSTITUTION:To receive the sound wave in the direction of a sound source A2, in directing the array direction X, X' axis of the microphones M1, M2 in the A2 direction, the output of phase difference depending on the distance (d) of the microphones M1, M2 is obtained and a sound wave is a synthesized wave as shown in Fig. 3. The signal is amplified at an output amplifier and obtained from an output terminal 7. Since it is desirable not to pick up the sound in the direction of an A3 when the microphones M1, M2 receive the sound of the A2 direction, the synthesized output of the microphones M1, M2 of the Y, Y' axis and the A1 direction is cancelled with opposite phase connection and to no output is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microphone device, in which a plurality of microphones have a phase difference to obtain power propensity, thereby reducing voices and noise of surrounding people other than the person who is speaking, making it easier to hear. This relates to device i'#.

Conventional microphone devices use a single microphone to convert the speaking voice or sound of the other party into an electrical output signal, which is then amplified by an amplifier. In particular, when multiple people are having a conversation, the sound that is passed through the microphone to hear a specific person's speech may be mixed with other people's voices or other noises, making it difficult to hear what is being said. It was a difficult situation. Although the structure of the microphone itself has been modified and improved in various ways in order to reduce the difficulty of listening even a little, there are currently no microphones that are sufficiently practical for the purpose of use. It's a situation where I can't find anything. Also, although some methods have been considered to impart some degree of directivity to the microphone, I have not found any that can be expected to have practical effects.

The present invention has been made to solve the above-mentioned problems. The gist of the present invention is to effectively increase the directivity of the microphone, increasing the sensitivity of the microphone for sounds coming from the direction you want to hear, and increasing the sensitivity of the microphone for sounds coming from other directions. ? It's like lowering it.

The microphone assembly RFC of the present invention will be explained below with reference to FIGS. 1 to 6. FIG. 1 shows the basic configuration of the microphone of the present invention. Ml and M are microphones arranged on the same plane with a certain interval d,
, The output terminals of the Wig are connected in reverse *r,:. 1.1' is the composite output terminal of the microphones M1 and Ma. In Fig. 1, AX, Aj, A'2, A11
indicates the direction of the sound source, and the arrows indicate the sound waves from each sound source. The sound wave of A1 is the microphone M
z and Ma at the same time, microphone M11
The outputs of M3 are at the same level and in the same phase, but since they are connected in reverse, they cancel each other out, and the output terminals 1.
1', no pneumatic output occurs. On the other hand, since the travel distance of the sound wave of Aj differs by d to each of the microphones Ml and Ml+, the corresponding sound pressure difference and phase difference are added to the microphones Ml and Ml, so that a vj force signal can be obtained. 0 Figure 2 shows the output sensitivity characteristics of the microphones in 360 degree directions when a constant sound pressure is applied from the periphery of the microphones M1 and Mll.

FIG. 3 shows the microphone Ml for sound waves from the sound source A1 or Aj, *s or A3 direction shown in FIG.

FIG. 4 is a diagram showing the phase waveform of Ma, and the relationship between the phase and the combined output sensitivity is shown in FIG.

FIG. 5 shows the frequency characteristics when the interval between microphones M1 and MI is set to 5 steps. FIG. 6 shows a configuration diagram of the microphone device of the present invention, where Mx and Ma are microphones, 2 is a switch, 3.4 is an amplifier, 5 is a volume adjuster,
6 is an amplifier, and 7 is an output terminal. Operation of the microphone device of the present inventionf,+i5iTo be clear, in order to receive the sound waves in the direction of the sound source All, the arrangement direction x of the microphones Ml and Ma, and the An output of the phase difference due to the distance d is obtained, resulting in a composite waveform shown in FIG. This output is amplified by the amplifier shown in FIG. 6, and multiple signals are obtained from the output terminal 7. As shown in Fig. 41, when the microphones Ml and Ml are receiving (picking up) sound in the direction of the pus, it is desirable that the sound in the direction of A or in the direction of A8 is not mixed in, so the sound in the direction of A1, Y,... The combined output of the microphones M1 and M for the Y'-axis sound wave is canceled out 71 by the reverse phase connection, so that no output is obtained. The sound waves coming from the direction A5 are attenuated due to the phase difference, as shown in FIG. Since the length of the sound wave varies depending on the frequency, if the microphones Mz and Ma are configured with an interval of 5α, the size will be sufficient to collect sound for next spring or recording. Assuming that the distance between the microphones Ml and Mg is 5 degrees, the frequency characteristics of this composite output signal will be as shown in FIG. In particular, for receiving speech such as conversation with a microphone, the characteristics shown in FIG. 5 are sufficient and can cover a frequency band that is easy to hear as sound.

Figure 2 shows microphone Ml and J in 360 degree direction of Ml.
This indicates the degree (total (1), value) of the microphone M.
1. The sensitivity of Ma in the array direction can be improved, and the combined output can be made close to 0 for sound waves in the direction perpendicular to the axis of the array direction, so the microphone can be moved in the direction of speech during conversation. By orienting the array axis, speech can be heard or recorded without being affected by surrounding noise. Also, a switch provided in the circuit of the Micropon MI 5M11 allows the microphone to be used by switching between directivity and non-directivity.

The range of frequency characteristics of the microphone device of the present invention depends on the interval between the microphones Mz and Ma, and the upper limit frequency is determined2, but for speech use it is 20011Z to 500Hz.
If this range, which is considered to be appropriate, is used, a flat characteristic can be obtained with an equivalent amplifier having a time constant of 795βS and 53μS. Equalization loss is dB ""
20 Lo,! i+ 53/7g5 ”'-23,5
It is a value that does not adversely affect the noise of the microphone amplifier.

As described above, the microphone device of the present invention can achieve directivity ' (r - +i:I with two microphones, so it has strong directivity and directivity that cannot be obtained with conventional directional microphones. Since sound waves in the direction perpendicular to the axis have the effect of being canceled out, it is possible to make it easier to hear the speech of a specific person in a conversation between several people with a microphone.
This effect is extremely large.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of microphones M1 and M3 of the device of the present invention, and Fig. 2 is a block diagram of microphones Mz and Mll of Fig. 1.
The sensitivity characteristic diagram in the 0 degree direction, Figure 3 is the phase waveform diagram that occurs depending on the direction of the sound wave received by the microphone in Figure 1, Figure 4 is the composite output sensitivity diagram of waveforms with different phases, and Figure 5 is the diagram. FIG. 1 shows the sound wavelength frequency characteristics of the microphone M1 in the arrangement direction when the distance between the microphones M1 and M bird is f 5 cm.FIG. 9 and FIG. 6 are configuration diagrams of the microphone device of the present invention. In the diagram, Ml, MIl microphone, and 21 switch. Figure 3 Figure 4 ml Gekifu (G) 2) Figure 5 Figure G

Claims (2)

[Claims] (1) Multiple microphones are arranged so that the combined output sensitivity of the multiple microphones is maximized for sounds in the direction in which the microphones are arranged. A micropon device characterized in that a plurality of microphones are connected so that the combined output sensitivity of the plurality of microphones is the lowest. (2) The microphone device according to claim 1, characterized in that a switch is provided on the circuit connecting the output of the mantissa microphone to switch between directivity and non-directivity.