Acceptance angle

The angle between points on a microphone’s polar response curve where the sound level drops by 3 dB compared to the on-axis level is called the acceptance angle of the microphone. It is also known as the coverage angle, opening angle or pickup angle. An omnidirectional microphone has an acceptance angle of 360° (it never drops 3 dB at any angle), a cardioid microphone 131°, a supercardioid microphone 115°, a hypercardioid microphone 105° and a bidirectional microphone (figure-of-8) 2 x 90° (front and back). Shotgun microphones have a frequency-dependent acceptance angle, usually narrower at high frequencies, typically less than 30°.