Comp is short for compressor, an effect used to control the dynamic range of a signal by reducing the difference between loud and quiet sounds. It smooths out peaks, adds sustain, and can make notes feel more even and controlled.

Compression is commonly used on guitar, bass, and vocals to improve clarity and consistency. Depending on the settings, a comp can be subtle and transparent or more noticeable, adding punch, sustain, and character to both clean and driven tones.