Speaker cables for Simaudio/ Dynaudio

I think it would help to know what you don't like about the sound now, and what you're ideally looking for. Granted, a cable may not fix or change everything/anything, but it helps to know your tastes.

I am looking for a tighter control of the bass and a greater clarity in the midrange and highs; an overall increase in transparency.

I would imagine it's very rare that someone has heard both of these cables with your amp/speaker combination, so in general the best anyone can do is venture an educated guess, which is going to be very general, since we also don't know what else is in the chain (front end and IC's). I have had the Nordost in my system and while they definitely provided increased clarity across all frequencies, and were very tight/fast cables, I ultimately found them a little on the analytical side of neutral. All the details sparkled, but a little too much. I was using them with a Dali Euphonia's, which have a ribbon tweeter, and the Pass INT-150 which in my opinion is close to your i-7, which I have also heard. The esotar tweeter in your Dyn's is remarkable, so this may not be a problem for you.

A buddy used the Teslas with his Dynaudio Contour 5.4s and thought they were excellent. This confirms my own experience of Synergistic Research, which I feel are very neutral cables. If I had to compare the two, I feel that the Nordosts focus you in on the minute details while the Syns make a more holistic presentation. Don't get me wrong, they're both excellent at detail retrieval, but in my experience I've found the Heimdalls to be a little more analytical. FWIW.

My source is a Simaudio Supernova cd. I am using a Nordost Heimdall xlr interconnect.

Well, one could assume you're already familir with the Heimdall in your system then. I would just bite the bullet and get the Heimdall from Cable Co or something, that way you can return it if you don't love it.