Microphone Tutorial Includes:
Microphone basics Microphone types Microphone specs Microphone directionality Dynamic microphone Condenser microphone Electret microphone Ribbon microphone Crystal / ceramic microphone Boundary / PZM microphone Carbon microphone
There are many different types of microphone that are a available. Each type of microphone has its own attributes, and different types of microphone are used in different applications so that the best performance can be achieved under any given circumstances.
The different types of microphone can be categorised in a number of different ways. Dependent upon the application, different approaches may be applicable. Sometimes the different types may be differentiated by they technology, other times it may be by the directional properties, and sometimes it may be by the diaphragm diameter.
Microphone technology types
Some of the major types of microphone technology include:
- Moving coil / dynamic microphone: This type of microphone is widely used for stage performances and many other applications. The moving coil microphone, has a small cone with a coil wound at its apex. This is held in a magnetic field and a current is induced in the coil as it moves in line with the sound vibrations. . . . . . Read more about the dynamic microphone.
- Condenser microphone: The condenser microphone consists of a capacitor of which one plate is the microphone diaphragm. As sound waves hit the diaphragm, it vibrates and causes changes in capacitance. This can be converted into changes in voltage. The condenser microphone gains its name from the fact that when it was invented, capacitors were called condensers. . . . . . Read more about the condenser microphone.
- Electret microphone : This type of microphone is effectively a derivative of the condenser microphone type. It is electrostatic capacitor-based and this eliminates the need for a polarizing power supply by using a permanently charged material. Although the technology has been used for some higher end microphones, it is normally associated with small microphones for use in electronic equipment. Here its size, and low cost of manufacture make it ideal for many applications where ultimate performance is not needed. . . . . . Read more about the electret microphone.
- Ribbon microphone : This is a form of high quality microphone that was widely used in the radio industry. Now it is less widely used as other types can offer equal performance more conveniently. It typically consists of a narrow aluminium ribbon which is corrugated to make it flexible. It is suspended between the poles of a magnet so that when the aluminium diaphragm moves, then a current is induced in the electrical circuit. . . . . . Read more about the ribbon microphone.
- Crystal / ceramic: The crystal or ceramic microphone uses the piezo-electric effect to generate voltages. It is found that certain substances create a voltage across them when they are stressed. In a crystal or ceramic microphone a diaphragm is attached to a slice of piezo-electric material and the sound vibrations pass to the diaphragm which in turn passes them to the piezo-electric crystal. . . . . . Read more about the crystal / ceramic microphone.
- Boundary microphone / PZM: The bounadary microphone offers a number of advantages over other types. It uses the boundary between the air and hard surfaces like a wall or a floor to enhance the sensitivity and also provide other enhancements to adding more naturalness to the sound etc. One popular incarnation of the boundary microphone is know as the PZM or pressure zone microphone. This name was introduced by the Crown Corporation for their incarnation of the technology. . . . . . Read more about the boundary / pressure zone microphone.
- Carbon microphone: The carbon microphone was the first practicable form of microphone and as a result it was used for many years was the main type of microphone available. It was based on the fact that when carbon crystals are compressed, their resistance reduces. . . . . . Read more about the carbon microphone.
Microphone directional properties
Microphones may also be categorised by their directional properties.
In some instances the directional properties of the microphone may be more important than the technology used. Accordingly it may be necessary to use a particular type of microphone according to its directivity.
The directional properties of a microphone are particularly important in many instances. Many have a directional response, like the popular cardioid response and this cuts out some extraneous noise. Omni directional microphones will pick up sounds from all directions. This enables the microphone to accept a variety of wanted sounds regardless of their direction, but increases the levels of background noise and also increases the possibility of acoustic feedback when used with public address systems.
Microphone diaphragm type
Microphones may also be categorised according to the diaphragm size.
The size of diaphragm can provide different characteristics, even for the same technology type of microphone. Accordingly sometimes microphones may be chosen for the type of diaphragm they use.
When choosing the microphone for a given application, it is wise to check its overall response and tailor it to the type of sounds it is required for pick up.