Simply put, a directional microphone works by sampling the timing differences between sounds arriving from different locations, for example the front and rear ports. The timing difference between these sources is used to attenuate sounds arriving from undesired locations.
- A Directional microphone can take several forms:
- single directional microphone with two sound entry ports
- one directional and one omni-directional microphone
- two omni-directional microphones
- a microphone array
It has been noted that whilst documentary evidence exists to demonstrate the improved speech performance with directionality, it always presupposed that the listener and sound source were situated in a defined manner (usually face to face). This is because the directionality worked by reducing the intensity of sounds from the rear, relative to sounds from the front. Whilst this ‘face to face’ format may be the predominant way a normal conversation is held, it is certainly not always the case and Adaptive systems are intended to provide some solution to this problem.