Editing Audio feedback (section)

===Frequency response===
Almost always, the natural frequency response of a [[sound reinforcement system]]s is not ideally flat as this leads to acoustical feedback at the frequency with the highest loop gain, which may be a [[resonance]] with much higher than the average gain over all frequencies. It is therefore helpful to apply some form of [[Equalization (audio)|equalization]] to reduce the gain at this frequency.

Feedback can be reduced manually by [[ringing out]] a sound system prior to a performance. The sound engineer can increase the level of a microphone until feedback occurs. The engineer can then attenuate the relevant frequency on an equalizer preventing feedback at that frequency but allowing sufficient volume at other frequencies. Many professional sound engineers can identify feedback frequencies by ear but others use a real-time analyzer to identify the ringing frequency.

To avoid feedback, automatic [[feedback suppressor]] can be used. Some of these work by shifting the frequency slightly, with this upshift resulting in a ''chirp''-sound instead of a howling sound of unaddressed feedback. Other devices use sharp notch filters to filter out offending frequencies. Adaptive algorithms are often used to automatically tune these notch filters.