Enter a tempo. See exactly how wide the mixable range is — including the half-time and double-time tracks most people forget about.
Bright center = clean match. It fades because the further you stretch, the more the pitch shift gives it away.
Most listeners won't hear a pitch shift here. This is where you can layer tracks almost blind.
The classic DJ pitch fader tops out around here. Comfortable, still musical, the working range most mixes live in.
Past here the pitch shift starts to color the track. Still usable with skill (or automatic correction), but know what you're trading.
No mental math. Drop songs in and Tuttii shows a match score for key and tempo before you commit to a mashup.