We continue with the Harmonica Microphones series with some thoughts on the knotty problem of microphone feedback: what it is and how to minimise it.
Feedback is that awful loud screeching, humming and/or whistling sound a system makes when a microphone picks up the sound from the amplifier’s speaker and sends it back to the amplifier for further amplification. Every system (in this case a microphone plus amplifier) has a feedback threshold. Turn the volume up loud enough and feedback occurs. Keep the volume below that point and it doesn’t. Unfortunately we often need to have our volume very close to the feedback threshold in order to be loud enough, and so feedback can come and go as conditions change. But some setups are less prone to feedback than others, and some microphones are less prone than others. (more…)