Directional microphone
The directional microphone is a type of microphone that primarily picks up the frontal sound and thus has a directional characteristic. Sound from other directions is converted into electrical signals more attenuated.
Exceptions
Since only pressure microphones or two-membrane microphones in a certain superposition mode have an omnidirectional characteristic , the vast majority of all microphones can be described as directional microphones. Directional models are:
- the broad cardioid , the cardioid , the supercardioid , the hypercardioid , the figure eight and the club .
The latter can be found in the shotgun microphone , the essential element of which is the interference tube .
All directional microphones are pressure gradient receivers .
application
Directional microphones with low sensitivity to sound outside of the direction of speech are a means of improving speech intelligibility in noisy environments. The shielding effect may be maintained even at a certain distance from the sound source to be transmitted .
Shotgun microphones make it possible to filter out individual signal sources from a distance. However, this effectiveness of the club characteristic is often overestimated. For this purpose, these microphones usually have longer sound tubes with several sound entry openings.
Nevertheless, the best possibility of increasing speech intelligibility remains if the speaker maintains a shorter distance from the microphone, since the effectiveness of the directional characteristic also decreases with directional microphones as the distance from the sound source increases. Sound interferences that can occur when microphones are used in close proximity (so-called popping) are avoided with a windscreen (popscreen).
See also
literature
- Thomas Görne: Microphones in theory and practice. 8th edition, Elektor-Verlag, Aachen, 2007, ISBN 978-3-89576-189-8
- Michael Dickreiter : Handbook of the recording studio technology. 6th edition, KG Saur Verlag KG, Munich, 1997, ISBN 3-598-11320-X
Web links
- Relationship of the microphone directional characteristics - from pure pressure receiver to pure pressure gradient receiver (PDF file; 77 kB)
- All microphone directional characteristics and other parameters (PDF file; 314 kB)
- Microphone directional characteristics in linear representation (PDF file; 168 kB)
- Difference between hypercardioid and supercardioid (PDF file; 118 kB)