Microphone pickup methods are: unidirectional, omnidirectional and bidirectional.
Unidirectional also refers to only one direction, which depends on the input source method. The input method is fixed in a certain direction before input or recording, which is called unidirectional.
Omnidirectional has a relatively wide acceptance range and can be received from different angles. The microphone picks up sounds from all directions and is equally sensitive to sounds from all directions. Ideal for capturing ambient effects in a room. Omnidirectional microphones cannot effectively reduce or eliminate unwanted sounds such as camera noise, ambient on-set noise, etc., while also not maximizing the main speaker's voice. ?
Bidirectional, it picks up sounds from both sides, not the front or the back. The use typical is to place it between two instruments, or two people facing the microphone, so that the two sounds can be recorded together while maintaining the independence of the two. Bidirectional microphones are primarily sensitive to sound coming from two directions. ?
Detailed information:
Microphone directivity
Polarity direction is also called the microphone's polar pattern, which refers to the microphone's ability to pick up sounds coming from different directions. Generally divided into omnidirectional, cardioid, supercardioid and figure 8.
Omnidirectional is also called non-directional. It has the same sensitivity to sounds in all directions. Cardioid is a directional microphone with the strongest front sensitivity and the lowest rear sensitivity. The supercardioid pickup area is narrower than that of the microphone cardioid, but the rear also picks up sound. The number 8 picks up sound from the front and back, but not from the sides (90 degree angle).
Baidu-Microphone Encyclopedia