1. Directional Microphone
The Directional Microphone has a preferred directional effect and usually only a front sound entry. With its pressure receiver it represents the simplest method for the transforming of sound pressure into electric signals. Polardiagram of a Directional Microphone:
2. Bidirectional Microphone
The Bidirectional Microphone has a side sound entry perpendicular to the main axis and receives sound from the front and back.
Polardiagram of a Bidirectional Microphone:
3. Cardioid Receiver
The Cardoid Receiver represents the constructive combination of directional and bidirectional characteristics. Microphones of this type have an additional sound opening behind the microphone capsule and only one preferred main angle of incidence.
Polardiagram of a Cardioid Receiver:
4. Special Forms:
Its Special Forms, the hypercardoids and supercardoids, have a greater directional effect in the main angle of incidence but are only rarely used in the recording of music. The elongated capsule construction has many side sound-entry openings. A broad cardoid type closely resembling the cardoid is encountered more frequently today.
The Pressure Zone Microphone is a special form of the directional microphone that can be placed on the floor or on walls - with interesting sound results.
[The way to the Classical-CD]