Microphones convert sound waves into electrical energy or audio signal. The diaphram in all microphones are basically the same. There is a thin piece of material that vibrates when hit by sound waves. The vibrations sent through the mic are converted into an electrical current. When the electrical energy reaches a speaker it is converted back into acoustic energy.
2 types of microphones are Condenser and Dynamic.
Dynamic microphones are good for general use. They are very simple. They are usually sturdy and tough. They are best suited handling high volume levels like from some musical instruments or amplifiers.
Condenser mircophones converts acoustic energy into electrical energy using a capacitor. These microphones need power from either a battery or an external source. There is a stronger audio signal than that of a dynamic. They are also more sensitive and responsive which makes them useful for capturing subtle noises and layers in sound. They are not good for high-volume noise because their sensitivity makes them prone to distortion.
Directional properties.
This explains sensitivity to sound from various directions. Some microphones pick up equal sound from all directions, some from only one direction or a combination of directions.
The three main categories are:
Omnidirectional
Unidirectional
Bidirectional
Omnidirectional microphones pick up sounds equally from all directions. This is helpful is many situations. Mainly for capturing ambient sound, sound coming from many directions and being a fixed positioned mic when the sound source is moving. It is not a good mic to use if you want to pick up sound from a particular subject because it is very general. There are 2 kinds of Unidirectional mics.
Cardioid means heart-shaped. These microphones pic up using a heart-shaped pattern. It mainly picks up sound from the front but some is picked up from the sides but only a small amount. This mic is good for general use. Handheld mics are usually cardioid.
Hypercardioid is variation of the cardioid pattern. It is similar but is an exaggerated version. It focuses on being directional at the front and gets rid of most sound from the back and sides. Because of the design of these mics they are usually known as shotgun microphones. This mic removes ambient noise, which can be a bit unnatural. The sound needs to be kept constant so it needs to stay pointed at the subject otherwise you will lose the audio.
Bidirectional microphones use a figure of eight pattern and it picks up equal sound from opposite directions. This isn't a very useful in most situations. One situation could be an interview with 2 people facing each other with the mic between them.
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