Hardware & signal path
CDJ
A CDJ is the club-standard media player: a jog wheel, a pitch fader, hot cues and a waveform display, playing from a USB stick, an SD card or a laptop. It carries no mixer of its own.
In practice
Two players and a mixer is the layout every club has, which is the argument for rehearsing on it.
Check the pitch range before you check anything else — the fader steps through ±6, ±10, ±16 and a wide setting, and a deck left on ±16 by the last DJ makes a 2 BPM correction feel like a twitch. Reset the tempo and the range between sets rather than trusting the player to have done it. Everything else you can prepare in advance: cues, loops and grids all live on the stick, so the work is done at home and the booth is only where you find out whether the export worked.
±6 · ±10 · ±16
Pitch ranges on the fader
USB, SD or link
Where the music comes from
Two decks + mixer
The layout to rehearse on
Where these come from: The standard control layout on club media players, not catalog figures — nothing we store describes the device a track was played on. For what we can measure, see what the pitch fader actually reaches.
Why it matters
It is the one piece of gear you can assume is there. A booth you have never seen will almost certainly hold two of these and a mixer, so the layout is worth learning even if you own something else — the transferable part of practising at home is the muscle memory, and that only transfers if the surface matches.
It also sets the limits you plan around. The pitch fader has a fixed set of ranges, the display shows you the grid rather than the music, and everything you prepared — cues, loops, grids — has to have survived the export onto the stick.
Frequently asked
What is the difference between a CDJ and a controller?+
A CDJ plays the music itself from a USB stick or SD card. A controller sends commands to software on a laptop and plays nothing without it. One is a player; the other is a surface.
Do CDJs still play CDs?+
Some models do and almost nobody uses the slot. Club playback is a USB stick or a link connection, which is why preparing a stick properly is the part of the workflow that matters.
What pitch range should a CDJ be set to?+
±6 for most beatmatching — it gives the finest control per millimetre of travel. Move to ±10 or ±16 only when the two tracks are further apart than ±6 can close.
Related terms
Pitch fader
The pitch fader is the slider that speeds a track up or slows it down, usually by up to 6 or 8 percent. It is how two records are brought to the same tempo before they are mixed.
Standalone player
A standalone player reads music straight from a USB stick or SD card. The decoding, the display and the cueing all happen inside the player, so nothing about the performance depends on a computer being awake.
Pro DJ Link
Pro DJ Link is the Ethernet network that joins several players and a mixer. One USB stick feeds every deck, the players share tempo and beat position, and lighting or recording software can read the whole rig from one connection.
Hot cue
A hot cue is a saved position in a track that plays from that point the instant you press its pad. Most players store eight per track, and they are stored with the file rather than with the session.
Explore: Pitch and tempo calculator · Mixing guides · Pitch fader · All DJ terms