1. Carbon particle microphone

Carbon particle microphones have a narrow frequency response range, low impedance, and are prone to distortion. Currently, only some telephones still use this type of microphone.

2. Crystal and ceramic microphones (piezoelectric microphones)

Good frequency response (80Hz~7kHz), high impedance, high output level, and low price.

3. Condenser microphone

A capacitive microphone consists of three parts: a polar head, a preamplifier, and a power supply (as shown in Figure 1). The electrode head is composed of a diaphragm and a plate. The diaphragm is an electrode of a capacitor, making it a simple capacitor. When sound waves in the sound field cause the diaphragm to vibrate, the distance between the diaphragm and the fixed back plate changes, resulting in a change in capacitance. This change in capacitance generates an AC voltage that varies with the sound pressure when it passes through the load resistor, and is amplified by the pre amplifier inside the microphone to output the signal voltage. The advantages of capacitive microphones include good frequency characteristics and flat frequency characteristic curves; High output signal level and low distortion; Non directional, high sensitivity, and good transient response performance. The disadvantage is that the working characteristics are not stable enough, and the low-frequency sensitivity decreases with the increase of usage time. Due to the need for DC power supply for the polarization voltage and preamplifier in the condenser microphone during operation, it is inconvenient to use it. Currently, the+12V or+48V phantom power supply is mostly equipped on the mixing console, which is used for the operation of the condenser microphone. Some capacitor microphones may have batteries installed inside the microphone, but their size and weight make it inconvenient to use.

Dynamic microphone is a widely used microphone in work. When the microphone picks up sound, the thin diaphragm moves and drives the coil to vibrate. The coil in the magnetic field converts it into an electronic signal, which is then sent to the mixing station for processing (as shown in Figure 2). Its advantages: it has good frequency characteristics, and the frequency characteristic curve is flat within the frequency range of 50Hz to 15000Hz; Good directionality and low noise; No need for DC power supply, easy to use, and reasonable price.

4. Wireless microphone

The wireless microphone utilizes wireless channels to transmit sound signals, and its system is divided into a transmitting part and a receiving part (as shown in Figure 3).

There are three types of microphones: condenser microphones, dynamic microphones, and aluminum ribbon microphones (rare).

Usage includes: recording microphone, instrument microphone, interview microphone, conference microphone, voice microphone, testing microphone, mobile phone microphone, KTV/performance microphone

Signal transmission: wireless, wired

In terms of directional features: omnidirectional, cardioid, wide cardioid, supercardioid, gun shaped, 8-shaped, stereo

The transmitting part is usually a handheld microphone, containing a transmitter and an internal battery; A lavalier microphone, headworn microphone, or instrument microphone, coupled with a built-in battery portable transmitter that can be clipped onto a belt. The receiving part has a receiving host with the same frequency as the transmission system, including an antenna, preamplifier, and signal cable connected to the mixing station. Wireless microphones are widely used, and users are not bound by the microphone cable and do not affect the visual effect of the audience.

The frequencies used in wireless microphones are divided into two categories: high frequency (VHF) and high frequency (UHF): high