Unity Gain
Definition
A state in which the output level of a device or processor equals its input level — neither amplifying nor attenuating the signal. A foundational reference point when setting up and calibrating a signal chain.
In Simple Terms
When something goes in at one volume and comes out at exactly the same volume — no louder, no quieter. It's the starting point for comparing whether a plugin is actually improving your sound or just making it louder.
In Practice
A compressor with no gain reduction engaged should output at unity gain so that bypassing it does not change the perceived level of the signal.