The application on my smartphone doesn't work correctly or the sound delays.

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.