sorry for the mess, moving and setting up a new studio, but enjoy this quick little guide (larger photos here http://sta.sh/2rr0v8cp9qj?edit=1)
CONNECT OUTPUT OF AUDIO INTERFACE TO INPUT OF INTERFACE:
SET TRAKTOR TO OUTPUT FOR DECK
USING “EXTERNAL INSTRUMENT” SET INPUT FROM INTERFACE.
a quick and dirty guide lol… on a side note, i wonder how abletons arpeggiator would work ontop of that
I tried that 5+ years ago mate. 
You don’t even need the “Ext. Inst.” device to do what you’ve said…
Also - I have a DJM-850 - so the routing has to happen internally, not in the physical world of cables…
The problem with routing Traktor into Ableton is the main reason you’d want to do it is to use the control vinyl which you can’t use because the audio interface has to be Traktor certified. Best bet is another DVS that doesn’t have that requirement.
but with ext instrument you can route the midi as well use the interface to sync
But you can only SEND midi from Ableton to Traktor.
I’m using timecode vinyl in Traktor - so - will Traktor’s midi clock follow Abletons?
My tests show audio coming in from a midi track.
that is a test we will have to try out 0_0 I am sure it will sync the tempos… I will give it a shot when i am done moving my gear. worst comes to worst someone can make a max4l shell to aide the process
People have been using Ableton as an FX rack for DJ gear for years.
Why dont you just look at one of their many setups for inspiration? ie Hawtin.
The trick is to use separate computers and audio interfaces, not to try to route it all with one computer. The latencies really add up.
And Ableton is garbage at midi sync. I used it for years of LivePA type stuff. Its famous for its midi slop. I gave up once I learned to beatmatch and just nudge everything now.
The other solution that the pros use is a hardware device that sends midi as audio pulses, ie Silent Way, Expert Sleepers type devices.
Use loopMidi to send traktor’s clock to ableton, use Jack to route audio from Traktor to Ableton, and you’re done. Get something like a Xone:K1 to control the channels in Ableton and you’re set.
with a pc on windows and to get a stable clock?