Guides · Harmonic mixing
Harmonic mixing, without the theory
The beats were matched. The levels were right. It still sounded wrong, and you could not say why.
It was the key. Every track is built from a set of seven notes. When two tracks play at once and their notes disagree, the bass lines and melodies rub against each other. Nobody on the floor could name it, but everybody hears it.
Harmonic mixing is simply choosing a next track whose notes agree with the one that is playing.
The one picture you need
Lay the keys out in a circle so that each one sits next to the keys it shares the most notes with. Number the positions 1 to 12. Use A for minor and B for major. That gives 24 codes, from 1A to 12B, and three rules:
- Same code. 8A into 8A. Always works.
- One number up or down. 8A into 7A or 9A. Six of the seven notes are shared.
- Same number, other letter. 8A into 8B. Exactly the same notes, heard from a different home. Minor turns to major, or back.
That is most of harmonic mixing. You can try it on the Mixkey wheel: tap a key and the safe moves light up.
The moves that change the room
Safe is not the same as interesting. A whole set of one-step moves can feel like it never goes anywhere.
- Two or three steps up gives a lift you can feel. Fewer notes are shared, so do it quickly or over a breakdown.
- Two or three steps down lets the tension out. Good after a peak.
- Four steps is a change of colour. Use it to start a new chapter.
When to ignore it
Key only matters while two tracks are heard together. If you cut from one to the next, or mix a drum-only intro over a drum-only outro, there are no notes to clash. Harmonic mixing is a way of knowing how long a blend will hold, not a rule about which records you are allowed to play.
And the detected key can be wrong. Software listens and makes its best call; tracks that change key, or have very little melody, catch it out. If your ears disagree with the code, trust your ears.
Where to start
Find the key of the track you open with, then look up what follows it. Already have keys written another way? The key converter turns them into wheel codes.