Dj Harmonic

Every track has a key. Know it before you drop it.

DJ Harmonic finds the key of a track and lights up the ones that will sit next to it, on a Camelot wheel you can read at a glance. Everything happens on your phone: no account, no upload, nothing to sign up for.

AN ENGINE WRITTEN FROM SCRATCH
Keys are found by harmonium, the algorithm built for DJ Harmonic. It listens to the track from start to finish, intros and breaks included, and answers in seconds. No modes to pick: it is always the full analysis.

TWENTY-FOUR SECTORS, A COLOUR EACH
Minor keys on the inner ring, major keys on the outer one, and a fixed colour per key. Tap a sector and it becomes the current key: compatible keys stay lit, the rest go dark. After a week you stop reading the codes and go by colour.

CAMELOT CODES OR CHORD NAMES
Read the wheel as 12A and 1B, or as C♯m and G, the way they sit on the circle of fifths. One switch at the top, and the app comes back the way you left it.

SIX RULES FOR THE MIX, AND A LOCK
From every compatible key down to a single move: all compatible keys, without cross tone transition, adjacent keys, energy boost/lower, semitone higher, compatible tone. With the lock closed the wheel only lets you move to a key that mixes; open, you go wherever you want.

THE KEY STAYS IN THE FILE
The key it finds is written into the track's tags, in MP3s and WAVs alike: open the track again and it is already there, in other programs too, and it travels with the file when you copy it to your computer. You decide whether to write it always, never, or to be asked each time.

TAGS YOU CAN FIX
From the track card, fix the title, artists, genre, year and many other tags, saved into the file. And choose which ones stay up front.

THE TRACK IN FRONT OF YOU
The key badge is also the play button. Underneath, the waveform scrolls by: breaks and drops at a glance, the played part in colour, and a drag takes you anywhere in the track, to the exact spot even in variable-bitrate MP3s.

KEYS THAT STAY UP TO DATE
Keys found by an earlier version of DJ Harmonic are recalculated with the new engine the first time you open the track again, with nothing for you to do. Keys written by other apps stay as they are.

BUILT FOR THE BOOTH
Light and dark theme, following your phone or set by hand. Five languages: Italian, English, French, Spanish, German. Portrait and landscape.

EVERYTHING STAYS ON THE DEVICE
No library to import, no cloud to sync, no account to make. Tracks never leave the phone, and the app works with no connection at all.