An electret microphone is a type of condenser microphone. The basic principle of a condenser microphone is to use a capacitor as an acoustic signal-electric signal converter. A plate of this capacitor can sense changes in sound pressure and play the role of ingesting acoustic signals. Usually this pole is composed of a metalized polymer film, and the other pole constitutes a variable capacitance whose distance between the poles can be changed. When there is sound pressure, the diaphragm vibrates, and the vibration intensity and frequency are determined by the immediate sound pressure, and the capacitance of the capacitor changes accordingly with the sound signal. If a constant voltage has been applied to the capacitor at this time, the change in the capacitance of the capacitor will cause the amount of polarized charge on the capacitor to change, thereby generating an electrical signal at both ends of the capacitor to achieve acoustic-electric signal conversion.
Certain materials can basically retain these charges permanently after adding charges. This is commonly referred to as electret materials. Microphones using these materials are so-called electret condenser microphones. The condenser microphone pickup unit has two poles, one pole is a metalized diaphragm that can vibrate, and the other pole is a metal pole plate. For electret condenser microphones, one of the poles is made of electret material or added with electret material, and the electret material itself can store electric charges, and the electret provides the necessary work for normal operation. Constant voltage. In this way, the part of the power supply voltage required for the work of the microphone pole is omitted, the structure is simple, and the volume is small.
The difference between electret microphone and condenser microphone
According to the location where the electret material is used, it can be divided into two types: diaphragm type and back pole type. Early electret microphones mostly adopted the diaphragm type, that is, the diaphragm was made of electret materials. The process was relatively simple and the technical requirements were not high. However, because the sound quality of the diaphragm made of electret material is not very good, the current electret microphones mostly adopt the back pole type, that is, the electret material and pole are attached to the other pole (back pole) of the capacitor. The material of the diaphragm can be considered from the perspective of sound pickup, and a diaphragm with a material with better sound quality can be selected. Judging from the current technological development, back-pole microphones are a trend in electret microphones.
The electret condenser microphone has the characteristics of small size, simple structure, good electroacoustic performance and low cost, and is suitable for mass production. It is widely used in meeting occasions, voice communication equipment, voice recorders, cameras, mobile phones and other products. However, the sound quality of electret condenser microphones is relatively poor, so it is mostly used in occasions where the sound quality is not high.
Condenser microphones have high sensitivity and high requirements on the surrounding environment. Therefore, recording studios are all condenser microphones. The stage performance environment is noisy, so dynamic microphones are more suitable. However, there is a special microphone. Although Audix vx5 is a condenser microphone, it is also suitable for On the stage, the unique VLM diaphragm enables the VX5 to still present the rich details and clarity of condenser microphones in environments where ordinary condenser microphones cannot give full play to their advantages. It is anti-feedback, has 10dB PAD attenuation, and can handle extremely high stage volume. VX5 has a wider pickup pattern, making it suitable for singers who want to fiddle with the microphone.