Are you still up for doing this? After moving, I finally am starting to get some free time. About two months ago I tried calibrating this to the new room it is in and the results weren't what I was expecting at all. I added my Klipsch sub to see if two subs would help and I think it is actually worse. During normal tv watching at around -15 volume, I can barely even hear the sub.
Keep in mind the room is a lot larger than before. It is now 27' x 22.5' x 12.5' (at the peak height).
This sounds like a set-up and digital bass management issue more than anything. I would take the Klipsch back-out - they don't have anywhere near the same FR and phase response and won't integrate very well.
The PB-4000 has lots of output capability, so it can easily fill this size room - we just need to make sure that:
the AVR is getting a bitstream DD 5.1 from your TV source(s) - many TV signals are default 2-channel PCM
the digital bass management settings in the AVR are optimized and the subwoofer is getting all of the redirected bass and the LFE .1 channel
the overall subwoofer calibration level is where you prefer it - many enthusiasts find the post-calibration baseline level match to be underwhelming