How to set up the Gemini SDJ-4000

The Gemini Sound SDJ-4000 is a standalone, two-deck DJ system with a built-in 4-channel mixer, so you don't need a laptop to play a set. Here's how to get it connected, powered on, and ready to play.

What you need before you start

A stable, level surface away from vibration and heat sources like amplifiers or spotlights.
An operating environment between 5 and 35 degrees C (41 to 95 degrees F). Outside that range the display can be hard to read or the unit can become unstable.
A USB flash drive formatted in FAT32, loaded with music compatible with the SDJ-4000.
Optional but recommended: Gemini's free V-CASE library management software, available at geminisound.com/v-case, to prep your tracks before you play.

Prep your music with V-CASE

You can play tracks straight off a FAT32 USB drive, but V-CASE unlocks the SDJ-4000's more advanced features. After you install V-CASE and add music to your library, analyze your tracks so V-CASE can calculate BPM and key, render waveforms, and store track data like cue points and beat grids.

Import your music (drag and drop, or use File, Import, Import Folder for a whole directory at once).
Analyze your tracks, then load one into the V-CASE player and check that the beat grid lines up with the first beat and the BPM looks right. Use the move tools to fix the grid if it's off, and use the metronome to confirm placement.
Add cue points if you want them. Each track supports up to 8.
Select a group of tracks or a playlist and choose Export to write them to your USB flash drive.

Connect your outputs

The SDJ-4000's rear panel gives you a few ways to get sound out of the unit:

Master XLR balanced output: connect standard XLR cables to your loudspeakers or amplifier system. Use the Master knob on the top panel to control the level.
Master RCA unbalanced output: connect standard RCA cables to loudspeakers or an amplifier system, also controlled by the Master knob.
Booth RCA unbalanced output: connect standard RCA cables for a booth monitor system, controlled by the Booth knob.
Headphones: on the front of the unit, accepts a 1/4 inch or 1/8 inch (6.35 mm or 3.5 mm) headphone plug for cueing and monitoring. Volume is set with the Phones Level knob.

Connect inputs, if you're using them

CH1/CH2 line input: standard RCA cables from an external line-level audio source.
CH3/CH4 phono/line input: standard RCA cables from a line-level or phono-level source, such as a turntable.
Each phono/line channel has a switch and ground post. Set the switch to match what's connected, and if you're using a phono turntable with a grounding wire, attach it to the ground post. A low hum or buzz usually means the turntable isn't grounded.
Mic 1 accepts a standard 1/4 inch (6.35 mm) cable; Mic 2 accepts XLR or 1/4 inch (6.35 mm). Both have Level knobs on the top panel.

Power on

Connect the included power cable to the power input on the rear panel. Power on the SDJ-4000 only after all of your input devices are connected, and before you power on your amplifiers and loudspeakers.

Load and play a track

Insert your USB drive into USB 1 or USB 2, then press the corresponding USB button to browse your music.
Use the Navigate knob to scroll through your list and press it to move forward, or press Browse to switch between the track list and waveform view.
Press Load 1 or Load 2 to send the highlighted track to that deck.
Press Play/Pause to start playback. Use the Channel Fader and Crossfader, along with the Channel EQ knobs, to mix between decks.
Set the Master Level and Booth Level knobs to your desired output volume.

Expanding your setup

The SDJ-4000's rear panel includes a Link port for a standard Ethernet cable, which connects to a computer, a switch, or another SDJ or MDJ player to share library resources. There's also a MIDI port that uses a standard USB cable to send and receive MIDI messages if you want to use the SDJ-4000 as a controller.

Once everything's connected and powered on in the right order, you're ready to browse your library and start mixing.