Phase describes the timing relationship between audio signals or parts of a signal as they move through a circuit or system. When signals interact in or out of phase, certain frequencies can be reinforced or cancelled, which directly affects tone and clarity.

In effects and audio processing, phase is most commonly associated with phaser effects and signal alignment in multi-mic or multi-amp setups. Managing phase correctly helps maintain fullness and definition, while deliberate phase shifting is used creatively to add movement and texture to a sound.