And then there were three
I took the PS1400 I was using as a LFE unit out of the system. Instead, I daisy-chained three HTPS400s as indicated in the owner's manual.
The HTPS400 subs are at the midpoints of the front, left side, and right side walls. They're crossed over at THX standard 80Hz.
At first, the added LFE info was overwhelming, inasmuch as I hadn't done any calibration other than putting the levels at midpoint. Taking out the ol' RS meter, I got the levels right.
The resultant improvement is quite satisfying. The LFE for HT is quite impressive as is the improvement on the multichannel sound from HDTV. However, the biggest enhancement is in 5.1 surround music, such as DVD-A and SACD.
Those little bastiges are quite the subs.