Audio
Acoustic Feedback
01 — Definition
The squeal or sustained tone that sets in when a microphone picks up its own amplified output and sends it round the loop again. The feedback frequency depends on room modes, microphone placement and EQ. Every 3 dB of EQ cut at a feedback frequency roughly doubles gain before feedback (GBF) at that frequency.
02 — In the field
Ring out the monitors before the show with the performer's microphone at show position — and do it with the performer in place: their body mass noticeably changes the acoustic environment.