I've gotten the impression that the 3a and Quattros are decidedly musically oriented. providing a well heeled, more laid back presentation without having great dynamics which definitely aid HT presentations. Jump factor and so forth. The lower eff ratings seem to support this as well... being 87db. Not sure on the imp.
is this true?
The idea Macdadtexas posted is a good one. to start with or stay with.
I started there, but didn't stop there. I bought an Odyssey Stratos SE plus + amp as the first outboard amp. Better indeed than simply my Onkyo 805. Fine.
Then, I thought to add another amp as you suggest. My preffs for sound come first nose to nose with sufficient power for the speakers of course. But I didn't want to spend a lot for that amp... yeah. Sure.
With more eff speakers than your proposed Vandy's, my power needs weren't so critical and I've seen from the SS Odyssey 150 170 was plenty! So I figured on getting an ATI multi ch amp, and sought out a few.... along the way I felt perhaps I should improve upon the Quality of sound the Odyssey puts out and get at least a 3ch amp so all the fronts were more cohesive. Following a few brainstorms, and a couple hicups, I decided to try the butler approach and do all the channels with the same influence and went with a 5ch TDB 5150.
Once in place and conected up with the Stratos driving the rears and the 5150 driving the mains and center, the sound was both more present, congruent and cohesive. A slam dunk improvement from just a receiver, or a reciever and a 2ch amp.
The additional benefitts are this... the tone of the 5150 which uses tubes in the ckt is that the amp has great stereo sound abilities. utilizing but 3 of the 5ch, the power reserves are greater than would be for all 5ch at once, and it does show it too.
However, for Vandys, in that size room (s), I'd think the tendency would be to raise the vol. More power than just 170-200+ probably is going to be needed in your application. That brings me back to ATI amps + either a rec or proc with HDMI 1.3a.
I'd also go with a Vandy center ch spaker or same same of your speaker choice there. rears could go either way depending on how critical you want to get. Vandys do seem to enjoy power. Do consider that too.
Go all HDMI 1.3a signal cabling and save a lot of $$$ without sacrificing much at all.
Luck to you.