Harmonic mixing

Harmonic mixing means choosing the next track by key as well as BPM, so that the seconds where both tracks sound together do not produce clashing notes. It is the difference between a transition that feels inevitable and one that feels like a cut.

The idea is old; the notation that made it popular is not. With Camelot or Open Key, deciding whether two tracks get along went from requiring a trained ear to requiring you to read two codes.

Two warnings belong together here. The first is that the rules in circulation tend to be narrower than reality: plenty of combinations a simple rule calls a clash sound fine. That is why our tools read from a transition table rather than from distance around the circle.

The second is that harmonic mixing is not an obligation. An abrupt key change, placed deliberately at the right moment, is a tool — and there are whole genres where the harmonic content is low enough that the question barely applies. The rule exists to keep you from clashing by accident, not to forbid clashing on purpose.

EnergyCurve uses it as one criterion among others when ordering, alongside energy.