To monitor sound with your headphones, you'll need to use the split cable that comes with the DDJ-200.

The issue may also be improved via different settings and operations.
To solve the problem, see the following information for the DJ software you're using.

WeDJ [here]
djay [here])
edjing Mix for iOS [here]
edjing Mix for Android [here]
rekordbox [here]

Three main factors can cause this and there are three possible countermeasures.

■ When USB connection and Bluetooth connection is established at the same time
If your smartphone is connected via Bluetooth and your PC/Mac is connected to the unit using a USB cable at the same time, you may not be able to control the app correctly.
Quit all applications on the PC/Mac, disconnect the USB cable from the PC/Mac, and reconnect it.

■ When the connection method is the cause
If you connect your smartphone using a USB cable, it may work correctly.
After disconnecting the USB cable, connect via Bluetooth from the setting screen on the app.

■ When the system environment is the cause
The following measures may work.
・If devices generating electromagnetic waves in the 2.4 GHz band (such as a microwave oven, wireless LAN or another Bluetooth device) are located nearby, move them away from DDJ-200 or stop using them.
・ If your smartphone is far away, move it closer to DDJ-200.

*If powered speakers or headphones are connected via Bluetooth or have the surround feature, the sound will be delayed.

The connection procedure may be the cause.
You cannot establish Bluetooth connection with your smartphone from the setting window of the smartphone when you use to connect Bluetooth headphones, etc.
In this case, a message such as "Pairing Unsuccessful" or "Couldn't pair with DDJ-200" is displayed.

Be sure to start the application before Bluetooth connection.
*You can't connect to a smartphone via Bluetooth automatically.

Three main factors can cause this and there are three possible countermeasures.

■When rekordbox setting is the cause
When the rekordbox is in EXPORT mode, click [EXPORT] on the upper left of the screen to switch to [PERFORMANCE].

■ When the connection is the cause
If you connect the DDJ-200 with your PC/Mac via Bluetooth instead of the USB cable, or if you connect the DDJ-200 with your smartphone via Bluetooth and the USB cable at the same time, you may not be able to control rekordbox properly.
When connecting the DDJ-200 with PC/Mac, disable Bluetooth connection and connect them using the USB cable.

■When your system (PC/Mac) is the cause
Mac
Follow the instructions in the guide [here]
Windows
Refer to case 5 in the guide [here]

You may solve the issue by doing the following:
- Disconnect any USB hubs and connect the unit directly to your PC/Mac.
- Disconnect any other USB devices.
- Quit all other applications.
- connect to a different USB port.

If the volume level is too high, the sound may be affected by distortion or clipping.
To solve the problem, see the followings.

WeDJ [here]
djay [here]
edjing Mix for iOS [here]
edjing Mix for Android [here]
rekordbox [here]

Three main factors can cause this and there are three possible countermeasures.

■When buffer size is the cause
If the buffer size is too low, sound cutting or noise may occur.
You can adjust buffer size in rekordbox [Preferences] < [Audio] < [Buffer size].
First, set a large value such as 1024. If the problem clears up, adjust to a value small enough that you can’t feel a delay (latency).
*The appropriate value depends on the system environment.

■When the connection or other equipment is the cause
An unstable USB connection with your PC/Mac may cause these problems.

To solve this, shut down your PC/Mac and disconnect all other USB devices and USB hubs.
Then, connect the unit directly to a different USB port.

■When your system (PC/Mac) is the cause
The following may solve the issue:
- Quit all other applications
- Disconnect from the internet and exit security software
- Turn off wireless connections such as Wi-Fi or Bluetooth
- Turn off power-saving settings
If your computer's system doesn't meet the requirements of rekordbox, it may cause the issue.
Read details on system requirements [here].

If you can't play audio files, check if the following applies:

• The file format is not supported by the application.
• The audio file wasn't downloaded from iCloud.
• The audio file was downloaded from Apple Music, etc.
• Only limited applications can play the audio file.

Two main factors can cause this and there are two possible countermeasures.

■When the connection or other equipment is the cause
An unstable USB-connection with your PC/Mac may cause this problem.
To solve this, shut down your PC/Mac and disconnect all other USB devices and USB hubs.
Then, connect the unit directly to a different USB port.

■When your system (PC/Mac) is the cause
The following may solve the issue:
- Quit all other applications
- Disconnect from the internet and exit security software
- Turn off wireless connections such as Wi-Fi or Bluetooth
- Turn off power-saving settings

If your computer's system doesn’t meet the requirements of rekordbox, it may cause the issue.
Read details on system requirements [here].

You can adjust the volume level of your headphones through the app.

[WeDJ for iPhone, WeDJ for Android]
Tap Gear icon > [Audio] on the top of the screen.
Adjust the volume level with the slider in [PRE-CUEING].

[djay for iOS]
Tap djay icon > Gear icon on the top of the screen.
Adjust the volume level with the slider (headphone icon) in [PRE-CUEING].

[djay for Android]
Tap djay icon > Gear icon on the top of the screen.
Adjust the volume level with the slider (speaker icon) in [PRE-CUEING].

[edjing Mix for iOS]
Tap Gear icon > [Audio setting] > [Pre-cueing] on the top of the screen.
Adjust the Volume level with the slider in [Volume].

[edjing Mix for Android]
Tap Gear icon > [Audio Settings] > [Volume] on the top of the screen.
Adjust the volume level with the slider in [Volume].

[rekordbox]
[rekordbox]
Click [MIXER] on the upper left of the rekordbox screen to display the mixer panel in the middle of the screen.
Adjust the volume level using the [LEVEL] knob in the mixer panel.

*If you feel that the volume level is still low, increase the volume level of your PC/Mac or smartphone and lower the volume of your powered speaker.

■ When the buttons are turned on in sequence the unit doesn't work properly, the firmware update may have failed.
Try updating the firmware again as follows.

1. Disconnect the USB cable between the DDJ-200 and your PC/Mac.
2. Restart the PC/Mac
3. Connect the DDJ-200 and the PC/Mac again with the USB cable.
4. Start the Update Program and execute the Update.