Here are a few suggestions for controlling feedback: To eliminate feedback, you must interrupt the feedback loop. This is what's happening when you see a guitarist hold his/her guitar up close to a speaker.)
(In fact many guitarists employ controlled feedback to artistic advantage. For example, the microphone could be replaced by the pickups of an electric guitar. Of course, there are many situations which result in feedback. One of the most common feedback situations is shown in the diagram below - a microphone feeds a signal into a sound system, which then amplifies and outputs the signal from a speaker, which is picked up again by the microphone. In technical terms, feedback occurs when the gain in the signal loop reaches 'unity' (0dB gain). It is caused by a 'looped signal', that is, a signal which travels in a continuous loop. Audio feedback is the ringing noise (often described as squealing, screeching, etc) sometimes present in sound systems.
