Problems with DJ io and Traktor Scratch Pro

[simulacra]

Hi guys, first post here~
I use a Numark mixtrack and DJ io, connected to the Traktor Scratch Pro software on my macbook. The problem is I can't get the audio right so that I can cue a track on say Deck B, before mixing it with Deck A. I have two sets of speakers and a pair of headphones at my disposal.

Any advice would be much appreciated Thanks!

[psyEDk]

how many audio channels does your interface have?
i'm not familair with the numark mixtrack or dj io.

you're going to need to set an output channel in traktors setup to be the headphone cue, and use the cue assign contol in traktor so preview your tracks before routing to the main mix.

i'm guessing you're mixing internally?