Trying to Eliminate Drone. Need Another Opinion.

With the Dynomax mufflers were they the super Turbo or the Ultra flows ? reason I'm asking is I run the super turbo's now on a 2 1/2 in system with balance pipe and don't get any droning where as before I had some 10in turbo mufflers don't know the brand ??? which would drone pretty bad around that RPM, around 40mph. Drove me nuts !!!:realcrazy: