A feedback suppressor is an audio signal processing device which is used in the signal path in a live sound reinforcement system to prevent or suppress audio feedback.
This technique works by introducing a varying shift in frequency to the system response.
Only modest improvement of gain before feedback is achieved[3] and the technique creates noticeable pitch distortion in music program.
[citation needed] Parametric equalization and notch filters are commonly used by sound engineers to manually control feedback.
The automatic notch technique is the most popular method and has the advantage that the sound is not colored until the system is at risk of feedback.