Dynamic microphone (dynamic microphone) [Engineering Acoustics] Dynamic microphone, dynamic microphone) is a device that converts sound into electrical signals. It is made using electromagnetic induction. When sound waves vibrate the metal diaphragm, the coil (called voice coil) connected to the diaphragm vibrates together. The voice coil vibrates in the magnetic field of the permanent magnet, and an induced current is generated in it. (Electrical signal), the magnitude and direction of the induced current change. The amplitude and frequency of the change are determined by the sound wave. This signal current is amplified by the loudspeaker and transmitted to the speaker, and the amplified sound is emitted from the speaker.
When the microphone receives sound waves, it acts on the diaphragm, causing the diaphragm to vibrate, driving the voice coil to vibrate correspondingly, and the voice coil moves in the magnetic steel to generate electromotive force, and the sound signal is converted into an electrical signal.
Dynamic microphones are relatively simple in construction, so they are economical and durable. They can withstand extremely high sound pressure and are almost unaffected by extreme temperatures or humidity
Moving coil microphones are mainly composed of coils, magnets, and shells.
Dynamic microphones are simple to use, do not require polarization voltage, are firm and reliable, have stable performance, and are relatively inexpensive. In teaching, karaoke, it is still widely used. But its transient response and high frequency characteristics are not as good as condenser microphones. Usually low noise, no need to feed power, easy to use, stable and reliable performance. The main features include:
1. Firm structure, stable performance, durable, low price; good frequency characteristics, flat amplitude-frequency characteristic curve in the frequency range of 50-15000Hz;
2. Good directivity;
3. No DC working voltage is needed, easy to use, and low noise.