djm 900 nexus with BUTT

Hi I hope someone can help as I cant find a soloution anywhere .

I do a live mix on internet radio station using 2 x xdj 1000 and nexus 900 using butt and shoutcast . Tried to do it the other night and sound was terrible . I have cable from rec out in mixer to line in on laptop any information would be great . In rekordbox I use nexus 900 asio driver or should I use nexus line in ? And in butt settings should I use nexus line in or default ?  Please help thanks in advance