3 Using Your Microphone
3.4 Feedback
Fig. 2: Microphone placement for maximum gain before feedback.
The term “feedback” means that part of the sound projected by a speaker is picked up by a micro- phone, fed back to the amplifier, and projected again by the speaker. Above a specific volume or "system gain" setting the sound system will start howling and the sound engineer will desperately dive for the master fader to reduce the volume and stop the howling.
To increase usable gain before feedback, the mi- crophone has a supercardioid polar pattern. It is most sensitive to sounds arriving from in front of it (your voice) while picking up much less of sounds arriving from the sides or rear (from monitor speakers for instance).
Tomaximize gain before feedback, place the main ("FOH") speakers in front of the microphones (along the front edge of the stage).
If you use monitor speakers, be sure never to point Refer to fig. 2. any microphone directly at a monitor or FOH
speaker.
Feedback may also be triggered by resonances depending on the acoustics of the room or hall. With resonances at low frequencies, proximity ef-
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