CDJ2000nxs2 djm900nxs2 rekordbox.

Have connected via usb to both CDJ's and back to my desktop running vers 6 Rekordbox.  Seeing both CDJ's but can only get slow distorted audio up one channel in performance mode.  

Have reinstalled Rekordbox and have a monthly core licence.

All brand new kit so hoped it would plug and play.

Have also tried via ethernet Link/switch and still no joy.

Any ideas or links much appreciated