I can't apply Serato DJ Pro FX to external input sound (PHONO/LINE/MIC).
The external input sound may not send to Serato DJ Pro.
Follow the steps below.
1. Move the input select switch to the [USB A] or [USB B] (where your computer is connected).
2. Move the input select switch back to the [LINE], [PHONO] or [MIC].
Please see "Using effects" in the operating instructions.
