Pitch

Pitch is the control that adjusts playback speed, almost always expressed as a percentage: +2% means the track plays two per cent faster than it was recorded. It is the fader used to bring two tracks of different BPM close enough to mix.

How far you can move it before it shows depends on the material more than on the gear. An instrumental takes more than something with a vocal up front, and a change that passes unnoticed in one genre is audible immediately in another. Player ranges run from a few percentage points to wide ones, and the practical limit is almost never the machine's: it is the ear's.

Without key lock, moving pitch moves key too, and the adjustment stops being only about speed. With key lock on, tempo moves and key does not.

For preparing a set this is what defines "close". Two tracks a few BPM apart come together without drama; far apart, the mix exists but asks for a different technique. It is one of the reasons ordering a set is not only about ordering energy: the tempo gap between neighbours is paid for too.