For your Information Pioneer Using the controller and external sound card does not work.

Connecting a DDJ SX to my desktop and connecting and external dac to the desktop.

When i use only the external dac, I can output sound to the speakers, but, when using the controller asio and external dac  is non functional.

@Phillip > Have you tried checking the audio settings within rekordbox to ensure you have the routing going where it needs to be?

Yes I have    I have tried every way possible.  Havent tried using a laptop.  but using a desktop   Not possible.  I can make a video of this and post it on youtube to explain.

The gear is a DDJ-SX   and a Creative SB1240 external  where the external power KRK 6  powered moniters via line out.

This is a pity since  it is generally agreed that external dacs are better than internal dacs..

Please look into this.