1, carbon-particle microphone
Carbon-grain microphones have a narrow frequency response range, low impedance, and are prone to distortion, and are still used by some telephones.
2. Crystal and ceramic microphones (psyelectric microphones)
The frequency response is good (80Hz to 7kHz), the impedance is high, the output level is high, and the price is cheap.
3, capacitive microphone
consist of a pole, a preamplifier, and a power supply (as shown in Figure 1). The pole is made up of diaphragms and plates. The diaphragm is an electrode of a capacitor, making it a simple capacitor. When the sound waves in the sound field make the diaphragm vibrate, the distance between the diaphragm and the fixed rear plate changes, so that the electrical capacity also changes, this change in electrical capacity through the load resistance to produce an AC voltage with the sound voltage changes, through the microphone built-in preamplifier amplified the output signal voltage. Advantages of capacitive microphones: good frequency characteristics, flat frequency characteristic curve; The output signal level is large and the distortion is small; Directionless, high sensitivity, and good transient response performance. The disadvantage is that the working characteristics are not stable enough and the sensitivity of the low frequency band decreases with the increase of usage time. As a result of the operation, the polarization voltage in the capacitive microphone and the front amplifier need DC power supply, resulting in the use of inconvenient, and now the mixer is basically configured on the s12V or s48V phantom power supply, is the supply of capacitive microphones for work, some capacitive microphones can be installed in the microphone, but large and heavy and cause inconvenient to use.
The dynamic microphone
is a widely used microphone at work, and when the microphone picks up sound, the thin diaphragm moves, the coil is vibrated by the diaphragm, and the coil in the magnetic field converts it into an electronic signal, which is then sent to the mixer for processing (figure 2). Advantages: It has good frequency characteristics and the frequency characteristic curve is flat in the frequency range from 50Hz to 15000Hz. Good direction and low noise; No DC power supply required, easy to use and reasonable price.
4, wireless microphone
Wireless microphones use wireless channels to transmit sound signals, and their systems are divided into transmit and receive parts (Figure 3).
There are three types of microphones from the type: capacitive microphones, dynamic microphones, and aluminum band microphones (rarely).
Used for: recording microphone, instrument microphone, interview microphone, conference microphone, voice microphone, test microphone, mobile phone microphone, KTV/performance microphone
Signal transmission: wireless, wired
Pointing to features: full pointing, heart type, wide-heart type, super-heart type, gun type, 8 character type, stereo
The transmitting part is usually a hand-held microphone with a transmitter and a battery; A microphone for a clip-on microphone, headset, or instrument must be attached to a carry-on transmitter with an internal battery that can be clamped on a belt. The receiving part has a receiving host with the same frequency as the transmitter system, has an antenna, preamplifier and signal line to the mixer, the wireless microphone is widely used, the user is not bound by the microphone line, and does not affect the visual effects of the audience.
Wireless microphones use frequencies in two categories: high frequency (VHF) and ultra-high frequency (UHF): high frequency range: 88MHz to 108MHz, and ultra-high frequency range: 450MHz-530 MHz.
tage: condenser microphone Karaoke microphone