I finally got my Thiel SS2 sub and have hooked it up. Pictures attached are of my front Thiel CS2.3s, Pioneer RPTV and the SS2 with the passive crossover. When the correct balanced cable comes, the crossover will go into my equipment rack.
Here are my first impressions (comparison is to the B&W ASW2500 sub, which the Thiel replaced):
1. bass is NOT chest-thumping or overwhelming. The SS3 I auditioned at the store had more "power".
2. the bass IS very clean and integrates very well with the rest of the sound.
3. Sub is much more involved in DD 5.1 movies and SACD/DVA-A with discrete .1 channels than with 2 channel music (even when listened to in surround mode). This may be because the low FR of the CS2.3s is good, and it may be that the passive crossover is set very low for the fronts. Thiel doesn't have a passive crossover for my center (SCS3) and I have powerpoints in the back, so I'm a little surprised that the sub is subdued on music.
Despite the low volume of output with non ".1" material, the music sounds great with clean and natural full-range sound.
I'll be calling Thiel tomorrow to make sure I have it set up correctly for the different sources.
The JL Audio Fathom I auditioned played louder and made me feel more rumble than this sub. My old B&W made more "booming" but was muddy. This sub was great for music, especially DVD-A or SACD, and very good for movies, with enough powerful bass (Star Wars Phantom Menace THX intro and pod races, Apollo 13 lift-off) for me. If you want the cleanliness of the SS2 with the "oomph" of the Fathom, spring for the SS3. Unfortunately, the SS3 is a monster, both in size and price.
I'll post more impressions after I speak to Thiel and finish calilbrating the system.