What a key is
Every track revolves around a home note and a scale, major or minor. "A minor" means the home note is A and the scale is minor.
DJs use the key to know whether two tracks will clash when they overlap. Two tracks in the same or neighboring keys blend smoothly. That's the foundation of harmonic mixing.
Finding it by ear
The traditional way:
- Open a keyboard, or a piano app on your phone.
- Play notes along with the bass or the main melody until one sounds like "home". That's the root.
- Listen for whether the track feels bright (major) or dark (minor).
Great ear training, but slow, and hard with effect-heavy electronic music that has no clear melody.
Finding it with software
Software measures how much energy each of the 12 notes has across the track, then compares that with the profiles of all 24 keys and picks the closest. Results are usually shown as a key name (A minor) or a Camelot code (8A).
With thousands of tracks, it's the only way to get through them in one evening.
Why key detection gets it wrong
No detector is 100% right, and the mistakes fall into a few familiar types:
- Relative major and minor mixed up: A minor and C major share the same notes, so they get swapped.
- A neighboring key: one step away on the Camelot wheel.
- Key changes partway, usually near the end.
- Mostly drums, with too little melody to go on.
- Recordings not tuned to 440 Hz, a few cents off.
The good news: the first two kinds of mistake still give you tracks that mix together. On the Camelot wheel, relative keys share a number with a different letter (8A and 8B), and neighbors are one number apart.
Converting to Camelot
Key names hide how keys relate, Camelot codes show it. An 8A track goes with 8A, 7A, 9A, and 8B. More in what is the Camelot wheel.
Faster with TaxonomyDJ
TaxonomyDJ detects key, BPM, and Camelot codes for your whole library, free, with no track limit. On 885 real tracks with the key in the filename, it matched the exact Camelot code 90.7% of the time, and 96.6% were harmonically mixable (exact, one number away, or same number with the other letter).
To put keys into tags, the start of the title, or filenames so other DJ software can read them, use the batch tag editor (Premium).