The ratio of processed signal to original unprocessed signal in an effects unit, controlling how heavily an effect is applied to the output.
Wet refers to the signal that has passed through an effect processor. Dry refers to the original unprocessed signal. The wet/dry ratio, often a single knob or percentage, blends the two: 100% wet means only the effected signal is heard, 100% dry means no effect is audible.
Why it matters
Dialing in the right wet/dry ratio is the primary way to use effects musically rather than destructively. Heavy reverb or delay sounds obvious and can obscure the mix; setting the wet level low keeps the effect present but natural.
In practice
Start any new effect at 0% wet and increase slowly until the texture is noticeable but the original transients remain punchy. For send effects on a mixer, the channel send level acts as the wet control against the dry channel signal.
