The Lighting Controller

Hi, I can't get the Beat from Operating system to function. I'm running audio from an external Focusrite Scarlet 2i4 - any tips as I've checked audio setup, is it because I'm using an external audio source? Thought it would pick up from audio wav output - have the beat icon switched on, tried beat setting in speed etc., but can't seem to trigger, any thoughts much appreciated.

Many thanks