Omnidirectional microphones: Magnetic, ceramic, and electret microphones are all omnidirectional microphones, that is, equal amounts of sound from all directions are accepted. At present, electret microphones are widely used in the field of acoustics. It is made of an insulating, permanently polarized material. When the sound enters the microphone, the density change of the sound wave causes the negatively charged thin metal diaphragm to vibrate, and then the sound energy is converted into mechanical energy. The diaphragm vibration generates pressure on the electret body and transmits it to the back plate of the electret. Both the back plate of the electret and the bottom of the diaphragm are connected with the field effect transistor preamplifier and have a terminal leading to the outside. When the diaphragm vibrates, the distance and space between the diaphragm and the back plate of the electret change, and a voltage is generated. The field effect transistor fixed on the microphone converts the mechanical energy into electrical energy, and then transmits it to the amplifier through the terminal. The electret microphone has a wide frequency response, high sensitivity and durability, and the diaphragm is its only moving part.
An omnidirectional microphone is different from a directional microphone. It belongs to the category of microphones.
The omnidirectional microphone is a portable conference phone product, which can not only use the computer interface to conduct high-quality Internet telephony conferences on the Internet; but also can use the headset interface as a speaker and microphone hands-free device for wireless mobile phones , Conduct high-quality wireless mobile phone conferences. Its shape is classic and easy to carry. The microphone pickup direction can be selected and set according to the meeting scene, which is suitable for use in meeting rooms and offices.
Most omnidirectional microphones on the market now use electret microphones. Therefore, omnidirectional microphones are also omnidirectional microphones. The difference between omnidirectional microphone and omnidirectional microphone is the characteristic. The omnidirectional microphone also has a speaker (or an audio output port). Therefore, the omnidirectional microphone can not only collect sound, but also output sound.
Because the omnidirectional microphone has both sound input and output functions, its circuit design must have an anti-echo (self-excitation, howling) circuit. Therefore, an important reference point for judging the quality of an omnidirectional microphone is its anti-echo ability.