I use the MPS2510P's that you see in the picture. However, I don't use M&K subs. I use Godzilla. A single Godzilla is equivalent and in many case's better than multiple subs by anybody.
A pair of Godzilla's ?....Forget about it. They would probably kill that lot you see in the picture. http://www.avforums.com/forums/showthread.php?s=&threadid=56100
Considering the size of the demo room, a few Godzillas would be needed as well.
In the recent interview Dr. David Griesinger (DG), chief designed at Lexicon, comments on a question by Philip Brandes (PB):
PB: Tom Holman is now demonstrating a very impressive 10.2 systembut where does it end? In your opinion, how many channels is enough for home use?
DG: I know Tom has been playing around with 10.2. With respect to bass reproduction, my work does suggest that having two subwoofers is better than oneif you define a subwoofer as below 80 or 100 Hz. I think it's very clear that phase and tonal properties are audible past 40 Hz in most rooms. That's even true in carsI've done experiments with 50 Hz in carsyou can hear the difference between one bass driver and two in a car. So that's important, and you can say that. Unless you assume that .1 refers to below 40 Hz only, and in that case 1 probably is enough.
Interestingly further in that interview DG comments on his ideal setup: five front speakers, 2 on the side, 2 at rear and 2 in the ceiling, and more subs the better.
Branxx, I think most know that two subwoofers are preferable in most if not all cases. I was pointing out that for a given output, one would need far less Godzilla's as proved in most THX subs failure to achieve the tougher THX Ultra 2 certification. As noted in my THX Ultra 2 thread, while multiples of other THX spec subs would be needed to reach these specs/levels, both the HGS-15 and HGS-18 did so on their own. May I also say that from my conversation yesterday with both Lucasfilm THX and Velodyne USA, they actually did so easily. For example, the distortion threshold alone was beaten by a massive margin. Great news for believers in this product, and bad news for snipers.
I found it incredible that no other current design (not brand new designs by Snell and a few more- including the now superceeded Vanilla flavoured THX spec) got anywhere near the Ultra 2 spec for subwoofers even though for years they have been quoting down to 20Hz and below.
There must be something in these Velodynes after all