Originally Posted by flyinrazrback
On the fence on these 3. My room is a sealed 3200 cubic space. I am looking to run one subwoofer and not duals. 100% HT use. I am sure all 3 would be great but trying to narrow this down.
I think that Jamie gave you good advice on going with the lower-tuned options. I believe you will be grateful that you did that. For instance, the V1811 only has about a 20Hz port tune, and it doesn't dig nearly as deep as the Cap 2400, or the FV25HP. To make it a fair comparison though, you should be considering PSA's new lower-tuned models, as well, instead of just the V3611.
The TV3612 (edited per Chucky's observation in the post just below) has a new Neodymium driver and about a 14Hz port tune. The TV36 iPal has an even better driver and the same ~14Hz port tune. Those subwoofers would give you all of the strong mid-bass that PSA subwoofers are known for, along with almost as much low-bass as the Cap 2400. (As Jamie said, the Cap 2400 pulls ahead of the other ported subs below about 11 or 12Hz.) The new PSA subs are somewhat larger and more expensive than the other models you are considering, but they have very strong SPL and good extension, combined with low distortion.
I don't want to promote one subwoofer brand over another. In my opinion, any of the lower-tuned subwoofers that I have discussed would be excellent for your situation. But, if you are really trying to narrow things down, I would personally lean toward either the Cap 2400 (or the Cap 2400ULF) for maximum low-frequency SPL and TR (tactile response); or I would lean toward the two new Neo (Neodymium) subs, from PSA, for a combination of more mid-bass and very good low-frequency extension.
It may help to read a bit on the various owner's threads, for the three brands, in order to form your own conclusions. I think that many people start to naturally group themselves somewhat, according to their personal priorities, if you really look for that.