[Marc Mühldorfer]

I have a problem that drives me mad (and I am lacking some special audio knowledge as well): Audio in Avid is brutally distorted and generally humming like hell.

I have the following setup:

A Mac Pro (early 2009) with a DeckLink Studio 2 card, an Alesis MultiMix 16 Firewire, 2 KRK Rokit 5 speakers and Avid Media Composer 6.5.

I connect the DeckLink card with 2 unbalanced (instrument) 6,3 mm/1/4 inch phone connector cables. Those go into the Line in 11/12 of my Alesis mixer (one channel). I think this is where the problems begin, right? Should I use balanced cables instead? What’s about mono/stereo? Are balanced cables mono or stereo or doesn’t it matter? Because I was assuming that both the two audio outs of the DeckLink and the two inputs of my mixer are mono, right? Just for info: I am connecting with the exact same cables via a Line6 KB37 audio interface to the mixer and there are no distortions or buzzes in Logic Pro at all.

Then there are the KRK Rokit 5 speakers. I connect them via the balanced TRS outputs to the Main Mix out of my mixer with unbalanced 6,3 mm/1/4 inch phone connector cables as well. I assume it is vital to use balanced cables here as well, right? Because right now I have a bit of humming going on as well only if I turn on the speakers (does the cable really make such a big difference or is there something else going wrong in my system?).

Basically I really would love to know (exactly) how to connect/cable my DeckLink Audio outs to my Alesis Mixer and to my KRK Rokit 5 speakers in order to have crystal clear sound in Avid.

Thanks so much for helping out an audio beginner.