Mixing in key, explained.

The key wheel

Every track sits in one of 24 keys: 12 minor and 12 major. The wheel lays them out so that keys next to each other share almost all their notes. Arcline gives each key a code from 1A to 12B. A is the inner ring of minor keys and B is the outer ring of major keys. The number is the position around the wheel.

Five moves

Arcline labels every transition with one of these. The colours match the app.

Tempo and pitch

Most DJs keep neighbouring tracks within about 6% of each other's tempo. Arcline shows the gap in the crate, for example +1.6%, and counts half and double time as a match, so a 174 BPM drum & bass track can follow an 87 BPM halftime one.

Speeding a track up without key lock raises its pitch. Around 6% is one semitone, which moves the key one step on the wheel by seven places. Try it:

With key lock on (most players have it), tempo changes leave the key alone. Arcline's blend preview changes speed without key lock, like a turntable.

Energy

Arcline rates every track from 1 to 10 on a fixed scale built from loudness, low-end drive, brightness and tempo. A 7 means the same thing in every crate, so you can compare tracks you've never played together. Each section of a track also gets its own rating, so a breakdown can read 3 inside an 8.

A set has a shape. Pick one when you press Build set:

Phrasing

Dance music is built in phrases of 8, 16 and 32 bars, and the big changes (a drop, a breakdown, a new loop) land on the first beat of a phrase. Start a blend on a phrase boundary and the two tracks' changes line up; start it two bars late and every change in the next track lands in the middle of the other one's phrase.

Arcline finds the phrase boundaries, names the sections (Intro, Main, Breakdown, Build-up, Drop, Outro) and puts hot cues A–H on them. Hot cues are in beta, so check them before a gig. If a track's grid is off, use −1 beat and +1 beat in the deck to move it.

Using Arcline

1. Add tracks. In the Library tab, drop in files or choose your music folder. Analysis runs on your computer and nothing is uploaded. No tracks to hand? Press Try an example track.
2. Check the read. Open a track in the deck: key, BPM, energy, sections and cues. Fix the beat grid if it's off.
3. Build the set. In the Set tab, pick a shape and a length and press Build set. Clashes show in red with Find a bridge.
4. Shape the transitions. In the Mix tab, drag blends to move them, drag their edges to change length, pick a style, and draw curves. Leave Hear edits live on to hear each change on a loop.
5. Take it with you. In Export, save a rekordbox XML with cues and a playlist, write tags into your MP3s, or render the whole mix to WAV or MP3 with a tracklist.

Writing tags and saving files needs Arcline open in Chrome or Edge on a computer.

rekordbox

Send cues and a set to rekordbox

1. In Arcline's Export tab, choose your music folder and paste its full path into the box. On a Mac, select the folder in Finder and press ⌥⌘C. On Windows, Shift-right-click it and choose Copy as path.
2. Press Save rekordbox XML.
3. In rekordbox: Preferences → View → Layout, tick rekordbox xml.
4. Preferences → Advanced → Database → rekordbox xml → Imported Library, and choose the file.
5. Open rekordbox xml in the sidebar, right-click Arcline set and choose Import.

Tracks that rekordbox has already analysed may keep their own cues and grid. Remove them from the collection first if you want Arcline's.

Bring a rekordbox playlist into Arcline

In rekordbox, choose File → Export Collection in xml format. In Arcline's Export tab, press Open rekordbox XML, pick a playlist and press Load into The Set. Tracks are matched by file name, so add the same music folder first.

Questions