4DJ is DJ software with the layout DJs already know: decks, mixer, effects and browser where you expect them. It goes further with stems made on your own computer, transitions that stay in key and in tempo, a tablet as a second screen, and controllers that map themselves.

• 2 or 4 decks with hotcues, loops, beatjump, slip, key lock and SYNC
• StemX: splits any track into drums, bass, other and vocals on your computer, nothing is sent online
• SmartSync: the next crossfade glides in key and in tempo
• Three-band EQ, filter, two FX units with 19 effects
• Library with playlists, smart playlists, instant search and import of collections from other DJ apps
• Audio recorder, microphone with talkover, loop recorder, live inputs and timecode vinyl
• More than 110 MIDI consoles recognised as soon as they are plugged in
• RemoteDeck: a tablet or phone becomes a second screen

BEFORE YOU START (one time only) After installing, open a terminal and type these two commands, then open 4DJ again:

 sudo snap connect 4dj-mixer:alsa
 sudo snap connect 4dj-mixer:raw-usb

• alsa: sound cards with separate master and headphone outputs, and MIDI consoles
• raw-usb: consoles with lights and jog wheels that talk over USB HID

The Snap Store does not connect them for you yet: without them 4DJ still plays music, but your sound card and console may not show up.

Consoles driven over HID (such as the Kontrol S2 MK3) also need a udev rule once: when you plug one in, 4DJ shows the command to copy into the terminal.