The Camelot wheel, start to finish — numbers, letters, and the tempo trap
Knowing a track's key is not useful on its own. What is useful is seeing, at a glance, which keys mix with which. Working out "what goes with A minor?" from music theory every time is not something you can do in the booth. That is why the Camelot wheel exists: it puts all 24 keys on a clock face and moves the answer from memory to your eyes.
This post walks through the wheel from start to finish: what it shows, why certain transitions work, how a compatibility score is built, and one thing that often gets skipped — tempo.
What the number and the letter mean
Every key on the wheel gets a number (1–12) and a letter (A or B).
- The letter is the mode. A is minor, B is major. 8A is A minor; 8B is C major.
- The number is the position. Neighbouring numbers sit next to each other on what musicians call the circle of fifths: they differ by a single note.
An example. A minor (8A) is built from seven notes: A B C D E F G. One step on, E minor (9A): E F# G A B C D. Six of the seven notes are shared; the only difference is F becoming F#. That is why your ear hears them as the same family.
An A and a B with the same number share the same seven notes. 8A (A minor) and 8B (C major) are the same notes; what changes is which note feels like home — the mood.
In short, the wheel turns "how many notes apart are these two keys" into distance. Close keys blend; the further apart, the more they clash.
The four basic moves
If 8A is playing, there are four safe places to go:
- Stay — 8A. Same key. Nothing to clash; the safest blend there is.
- Energy up — 9A. One step clockwise. Same mood, lifts the room.
- Energy down — 7A. One step back. Same family, calmer.
- Mood flip — 8B. Same number, other letter. Same notes, different feeling: going from minor to major brightens the track.
Beyond these, two steps (6A, 10A) and the diagonal neighbours (7B, 9B) usually work too, but fewer notes are shared, so the length of the blend and how melodic the tracks are start to matter more.
All of these moves for every key, on one page each: 8A and all 24 keys.
How a compatibility score is built
The wheel gives you direction. To sort hundreds of tracks against whatever is playing, that direction has to become a number. This is the score Harmoniq uses to rank your library:
| Move | Example (from 8A) | Score |
|---|---|---|
| Same key | 8A | 100 |
| One step | 7A, 9A | 88 |
| Mood flip | 8B | 85 |
| Two steps | 6A, 10A | 62 |
| Diagonal neighbour | 7B, 9B | 55 |
| Further away | 6B, 5A … 3A | 29 down to 10 |
Anything from 55 up is workable; below that the scales stop overlapping enough, and the blend rubs however short you keep it. The full table is on every key page, with the same numbers as the app — the reference pages are generated from the engine's own function, not written by hand.
One note: the score does not only measure note overlap, it also accounts for a change of mode. The diagonal neighbour 9B (G major) actually shares six notes with 8A; two steps away, 10A shares five. Yet 9B scores lower, because you are moving around the wheel and switching from minor to major at the same time. Two changes at once, so the score keeps it one notch below two steps.
The tempo trap: the pitch fader moves the key
This is something even DJs who know the wheel can miss in the booth.
When you change a track's tempo with key lock off — like spinning a record faster — its pitch changes too. The maths is simple: one semitone is a frequency increase of about 5.9%. Push the pitch fader to around +6% and the track is a semitone higher.
On the wheel, the result is surprising: one semitone up is seven steps forward. That is because neighbours on the wheel are a fifth apart, not a semitone.
- An 8A (A minor) track sped up about 6% → becomes 3A (B♭ minor).
- The same track slowed down about 5.6% → becomes 1A (A♭ minor).
On paper you prepared a perfect 8A into 8A blend. But if you pulled the incoming track from 124 BPM to 131, you are now playing 3A against 8A. In our engine's score that is 10: the lowest value on the table.
Smaller shifts are not harmless either. At around 3% the track has moved half a semitone: right between two keys, sitting on neither. It may not sound like "the wrong key" so much as "slightly out of tune".
In practice there are three options:
- Turn key lock on. Master Tempo in Rekordbox, Keylock in Serato and Traktor. Tempo changes, pitch stays. On big shifts it can colour the sound, so still check by ear.
- If you leave it off, work out the new key. Around +6% is seven steps forward, around −6% seven steps back. Look across the wheel from 8A — that is where you land.
- Pair tracks with close tempos. Keeping the shift small is still the cleanest fix.
The wheel is only as good as the label
Everything on the wheel rests on one assumption: that the key on the track is right. If the label is wrong, the wheel confidently points you the wrong way, and a blend that scores 100 on paper clashes in your ears.
We wrote a separate post on why two programs can give the same track different keys. The short answer: in some tracks the evidence genuinely splits between two keys. That is why Harmoniq shows a confidence score next to every key and flags tracks below 80. In our measurement, 69.3% of tracks land above that line, and 94.3% of those agree with the Mixed In Key label. For the rest, listen to the section you plan to play before trusting the wheel.
Quick summary
- The number is the position, the letter the mode: A minor, B major.
- Four safe moves: stay, one step forward, one step back, flip the letter.
- A score weighs note overlap and mode change together; 55 and up is workable.
- With key lock off, 6% of tempo is seven steps on the wheel.
- The wheel is as trustworthy as the label on the track — and knowing how sure that label is belongs to the job.
If you want to see where your own library lands on the wheel, drop your tracks into the app. Analysis runs in your browser; nothing is uploaded.