A compressor is an electronic device or algorithm that attenuates the amplitude of an audio signal when it exceeds a defined threshold. By lowering the volume of loud peaks and allowing the overall gain to be raised, it narrows the difference between the quietest and loudest parts of the signal. It is heavily used in broadcasting, recording, and public address systems to prevent clipping and keep vocals intelligible.
Heard on the job
Put a compressor on the microphone input so the announcer doesn't blow out the speakers when he shouts.