MEMS silicon microphones can be divided into three categories: dynamic coils, capacitors, and aluminum strips. They have different radio principles, so they will be used for different instruments. Large recording studios are usually equipped with different types of microphones to meet different needs. Professionally speaking, all microphones are converters that convert sound pressure changes in the air into voltage changes in analog circuits. The analog signal then enters the audio interface and becomes a digital signal presented on the computer. The diaphragm of a MEMS silicon microphone vibrates with the vibration of sound waves, and the circuit connected to it converts this vibration into an electrical signal. Different microphone designs will have different signal conversion methods, as well as different transient and frequency responses.
The directivity of MEMS silicon microphones varies.
Omnidirectional microphones can receive sound from all
directions. The dual directional microphone will block both
sides and only receive front and rear sound. Other
unidirectional microphones only receive sound in front of the
microphone, but their sensitivity is also different. Most MEMS
silicon microphones have only one direction, and some
microphones can choose different directions.
Dynamic MEMS silicon microphones, as a common type, convert
sound signals into electrical signals through coil motion and
electromagnetic induction. There is a suspended diaphragm
connected to the coil inside the microphone, which vibrates back
and forth with the sound in the magnetic field. This vibration
occurs in a magnetic field, generating analog electrical signals
that are consistent with sound. This design makes the mobile
microphone less susceptible to damage, and singers and musicians
often use it during live performances. In recording studios,
dynamic MEMS silicon microphones are often used to record
high-volume instruments, including guitar bass speakers and
single drums in drum sets. Most dynamic microphones are
heart-shaped or supercardioid, making them ideal for close range
live music pickup. Some dynamic microphones may sound beautiful,
but generally speaking, they are not as soft as aluminum ribbon
microphones and not as bright as condenser microphones.
As the name suggests, capacitive MEMS silicon microphones use
capacitors to convert sound into current, and dynamic
microphones do not have coils. Capacitive microphones require
phantom power supply. Most new capacitive microphones on the
market can simply use a mixer or audio amplifier in the audio
interface to provide a 48VDC voltage. Some old-fashioned
capacitive MEMS silicon microphones and replica models require
special power devices to connect the microphones.
Capacitive MEMS silicon microphones are divided into two types:
large diaphragm and small diaphragm. Due to its lightweight
diaphragm, clear and bright sound, and rich details, capacitive
microphones are widely used in recording studios. Large
diaphragm microphones are often used for vocal recording, while
small diaphragm pencil microphones are mainly used for
instrument recording. The same model of capacitive microphones
will also form a pair for stereo recording. Large diaphragm
capacitive MEMS silicon microphones are usually designed to
point to the side, with the diaphragm facing both sides of the
microphone. Sometimes there are two sets of diaphragms
back-to-back, so that users can adjust to different pointing
modes. Higher priced microphones will adopt this more flexible
design, while the cheaper version only provides heart-shaped
pointing while ensuring sound quality.
