Originally Posted by JimWilson
I believe SVS has some on their website.
The difference between the SB-1000 and the PB-1000 is really two-fold. The first difference is deep extension - the PB-1000 does extend deeper. The second difference is max output in the deep bass regions - while the two subs have similar max output in the mid/upper bass regions, the PB-1000 has considerably more max output than the SB-1000 in the 18-36 Hz octave. This should really come as no surprise - it has a much larger cabinet volume and a 3.5" deep-tuned port, both of which contribute to higher max output at the deeper frequencies. This is similar to comparing say the SB12-NSD and the PB12-NSD.
As owners are discovering, the SB-1000 has a wonderful articulate sound, gets plenty deep in-room (as evidenced by the flat to 20 Hz FR chart posted previously), and also has surprisingly high output and punch. It's a fantastic choice for smaller rooms which don't need extreme output from the subwoofer, and also where ease of placement and low visual impact are also priorities.
The PB-1000 is a better choice for larger rooms at higher playback levels where more sheer output in the 18-36 Hz octave is needed, and a somewhat larger and more visible subwoofer is not an issue for the owner.