I agree that you should attempt to take it back to the installer and see if he can (and will) attempt to adjust it more to your liking. However, I'd say this was your first hard lesson in Audio. Never purchase speakers without first taking time to listen to them, and do so with music your well familiar with.
The real problem here I suspect is the Type of tweeters the Triton's use. The vast majority fall into one of two categories: Hard Dome and Soft Dome. Some people (myself included) find many Hard Dome tweeters (typically a Metal Cone material) to be Harsh sounding. It's the resonance sound of the metal itself. Toning down the tweeters will help a little, but you can't EQ out that resonance tone.
This is why whenever someone asks what kind of speakers they should buy I ALWAYS recommend going out and listening for themselves. No one can tell you what will sound good To You.