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"Omnidirectional" electret mic

Discussion in 'General Electronics Chat' started by Razor Concepts, Dec 18, 2009.

  1. Razor Concepts

    Thread Starter Senior Member

    Oct 7, 2008
    I am just wondering why some electret mics are called omnidirectional. Does this just mean the source of sound doesn't have to be straight along the axis of the mic, and it will still pick it up well?
  2. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    They simply have the diaphragm as one surface of an otherwise sealed capsule.
    Air pressure changes from sound waves will be sensed to some extent pretty much regardless of direction.

    Directional electret inserts typically have a ring of vent holes behind the diaphragm, plus internal vents in the diaphragm mounting plate, allowing pressure to reach both sides of it.
  3. BMorse

    AAC Fanatic!

    Sep 26, 2009

    here is what wikipedia says....