Before trying any of these steps, it may be worth a simple reboot of your computer. Unplug the DDJ-400 before you start.
1. Check that the computer recognizes it as a USB device
- With the unit powered-on and connected via USB, open the System Report by click the Apple icon > About this Mac > System Report.
- In the left pane, click Hardware (if not already open) > USB.
- On the right, look for the DDJ-400 and click it to see if the details are provided.
Not recognized? Try using a different USB cable and/or USB port on your Mac.
2. See if the OS recognizes it as a MIDI Device
- Open the Audio MIDI Setup app.
- Open the MIDI Studio window if it's not open; Window > Show MIDI Studio.
- See if the DDJ-400 appears in the window with a solid color.
- If it does not appear or you feel this may be part of the problem, you can try creating a new MIDI Configuration.
- Click the drop-down (currently showing Pioneer DJ in the image above) and select New Configuration...
- Give the new configuration a name and click OK.
- The connected devices will be scanned and your DDJ-400 should appear.
3. Check the audio device
- Open the Audio MIDI Studio app.
- Open the Audio Devices window if it's not open; Window > Show Audio Devices.
- Verify that the DDJ-400appears as an audio device with a 0 ins / 4 outsconfiguration.
4. Ensure proper configuration within rekordbox
- Launch rekordbox and switch to Performance Mode if you are not already.
- Open the Preferences and see if the DDJ-400 is selected as the audio device.
- Scroll down and verify that the Master Output is set to DDJ-400 : MASTER and the Headphones Output is set to DDJ-400 : PHONES.
- If you scroll to the bottom, you should also see the DDJ-400 listed beside Control Device Information.
5. Reset the rekordbox MIDI configuration
- If the rekordbox preferences are set correctly but you still have issue with control, verify that the rekordbox MIDI configuration hasn't been switched.
- On the main rekordbox window, click the MIDI button from the top bar.
- With DDJ-400 selected lick the DEFAULT button at the top right of the pop-open MIDI setting window.
- You will be asked if you want to export the current settings, choose Yes (and save the file) or No (to discard changes), and the DDJ-400 MIDI defaults will be restored.
- Close the MIDI settingwindow.
6. Check Operation
- With a song playing on each channel, adjust the channel TRIM knob on the DDJ-400 until you see activity on the channel meter LEDs.
- Push each of the channel faders to the top, and adjust the master LEVEL knob so you have output on the master channel.
- Ensure that your output device volume is turned up to hear the incoming signal.
7. Headphone Cueing
- To hear the audio for any channel in your headphones, press the individual channel CUE button, and adjust the headphone MIXING knob to the far left.
- To hear the audio from the master, press the master CUE button, and adjust the headphone MIXING knob to the far right.
- To hear a mix of both sources, have one or more CUE buttons illuminated, and adjust the headphone MIXING knob as desired.
- The headphone LEVEL knob will adjust the volume on the headphone output.