Could you please share your room size? I'm interested to know if I need to have 2 Ultra's for my room size, or if 1 Ultra and 1 Plus would be good enough.
I'll also contact Ed and see what he says.
I've been running a pc12 plus and a pc13 ultra for about a year now; the combination is excellent, as long as they're well calibrated.
when calibrating, one must not forget to take into account the difference in max output of each sub. so that the smaller one is not overdriven.
if you listen to movies at Reference Level, then i suggest you use 2 pb13 ultras. because of room size.
room placement and a good calibration will also make a good difference.
have a look here: http://www.blu-ray.com/community/gallery.php?member=Gelli