Ok, recently I've been working on fine tuning the system.
The speakers have been repositioned over a period of time and I have found a great spot and angle for each one.
I bought a Pioneer Elite Vsx-91txh not too long ago, which made a huge improvement on sound quality. I can definitely tell the amplifier section is better with the bass. There's so much more impact and intensity with it.
Recently, I decided to test the limits of output and played what I guess you would call pop-rock with a lot of 30hz range synthesized bass and deep sounds.
I have 4 12" Drivers - 2 have about 10mm Xlim and the others about 20mm (2dB more efficient too) tuned around 35hz for the system. I guess a 60mm Xlim 12" driver (much lower Xmax) driver would be equivalent, but one with lower acoustic impedance (or higher, don't remember which).
Volume Control: -40dB The bass is definitely present, but no visible cone movement.
-30dB There's now a lot more intensity, barely visible cone movement.
-20dB Now the cones a moving a little bit and I'm starting to feel the bass a little.
-10dB The cones are moving a bit more and I'm really feeling the bass now.
0dB The cones are not at their extremes, but are definitely moving a LOT. The bass is felt everywhere and it sounds great.
+6dB As loud as I was willing to go (maybe slight clipping at the worst), the driver excursion was about as high as I was comfortable with and the pictures were starting to move around on the wall more than I was comfortable with so I turned it down. Since it was too loud to actually listen to clearly I went outside so I could hear it (you know what I mean?) and it sounded just like it did at lower volumes, except the bass wasn't as strong (dynamic compression, I'm assuming). It was fun watching 4 12" drivers moving a lot.
I am still trying different things to improve the sound image I see if I close my eyes.
I'm very pleased with this receiver. The bass is much better sounding than it was with that Paradigm UltraCube 10, but I am still not quite sure why...
Ah...well anyway a new DVD Player (cheapie right now) and a dual 18" LLT will be on their way when the time is right.