Pat,
Is the current distance (i)between speakers and (ii)between speaker and listing spot the same as your prior setup? The prior setup was a very near field listening arrangement as I recall; with side walls so far apart, a carpeted floor but bare ceiling, you would have heard a lot of direct sound and less indirect sound, so you'd be hearing more of the tweeter.
Now if you are listening further away and you are absorbing side wall 1st reflections (which is somewhat of a proxy for the distant side walls of your prior arrangement) then the tweeter may sound softer. The other reason that the tweeter may sound less loud is that the bass and/or mids are louder relative to the highs and that the highs are just the same as before. The bass could very well be louder given the new location and the shape of the front wall 'trapping' and storing bass energy. Are you using bass traps in the front wall corners? If so, then experiment with different air space depths to alter which bass frequencies are impacted the most.
So net net, try to attenuate the bass (e.g. traps, move speaker farther away from front wall) or accentuate the highs by leaving a bare side wall at 1st reflection points.
Sounds like I might have to swing by again but this time with my handy dandy Dayton Audio OmniMic measurement tool. I could bring along some RPG Skylines and/or GIK D1 dffusers to try on the ceiling and/or side walls for fun.
cheers,
kevin
