Track energy

A track's energy is how hard it pushes — how much intensity it puts on the floor while it plays. It is summarised as a number from 1 to 10 because that is the scale DJs already carry in their heads, the one Mixed In Key popularised, and changing it would only add one more mental conversion.

It is a simplification, and it is worth saying so. A track does not have a single energy level: it has a breakdown that drops away, a build-up that climbs and a drop that lands. The number summarises all of it — useful for ordering, useless for describing the track's insides.

One difference from Mixed In Key is worth keeping straight: their 1 to 10 scores each track on its own, and ours is used to score the whole set. A set of nothing but tens does not score ten. It scores lower, because it goes nowhere.

Where the number comes from depends on what your tracks carry. If they have BPM in their tags, the engine uses it as a first reference; if they carry an energy tag from another program, it respects that. When a track has nothing to estimate from, the product says so instead of inventing a number.