A processor is a piece of audio equipment or digital unit designed to shape, modify, or manage sound using effects, modelling, or signal control. In music gear, processors can handle tasks such as reverb, delay, modulation, dynamics, amp modelling, speaker simulation, and multi-effects processing, often within a single device.

Processors are widely used in studio, live, and home setups because they offer flexibility and consistency. They can replace multiple individual pedals or rack units, allow precise control and presets, and are commonly found in guitar rigs, recording systems, PA setups, and modern digital workflows where efficiency and repeatability are important.