TTI exhaust too loud

i just put on a full 2.5 tti exhaust on my 70 Dart with manifolds and magnaflow super turbo's. The system went on very easy everything lined up no problems with fit no hacking no cutting. That was the good part the exhaust is very loud in the car. All kinds of strang harmonic sounds and vibrations. It sounds good at 1900 rpm but makes your head hurt around 2100 rpm and again around 3100. The car sounds good outside. You just can't drive it without all the new resinence Nothing hitting or rubbing and the old exhaust did not do this. Is there anything I can do or is this normal for a tti system. Has anybody had any luck with this system and another muffler?