They rock bi-amped as I have a Triangle T17FLV 608 Mid bass and they sound great with any music, fast and open. not too bad without a sub.
Triangle speakers not for rock?
I was considering buying some Triangle Heliade's to match with my Onkyo A-9555 in my apartment, but heard they don't sound good for rock. I don't exactly know why though. Right now I have Heresy's which some might consider bright and little bass like the Triangles, but they seem fine to me for rock.