When I slide the crossfader, the sound doesn’t change. Even if I slide the crossfader all the way to the left/right, I can hear the sound from the other deck. What should I do?

Crossfader Assign may not be set the way you want the crossfader to work.

 

You can change the settings on the [UTILITY] screen or the [CROSSFADER CURVE] on the [Mixer Settings] screen.

For details, see [Settings] > [Changing the settings] in the Instruction Manual.

 

You can read the Instruction Manual [here].