Apologies for bumping a thread that's over a year old, but it showed up while I was searching for sub information so I figured I'd add some personal insights that are relevant to the topic.
I'm a big measurements guy, and tend to shy away from any audio equipment for which objective data is minimal, questionable, or absent entirely. I recently swapped from dual HSU VTF-3 MK5s to Monolith 15" V2s. The Monoliths were fantastic, but my curiosity got the better of me and, while keeping my fingers crossed, I ordered a pair of PSA TV2112Ms in an attempt to land on true "end game" subs.
For those concerned with their ULF performance, I am finding them to be excellent in that regard. Subjectively, they integrate with my mains at a level that I haven't experienced with prior subs. They are exceptionally pleasing for music and offer loads of dynamic range. They come alive with the lightest bass notes and reproduce them with a level of delicacy and finesse that I've not heard before. When fully woken up they're enough to create a true earthquake in my house, even when two floors up (just ask my wife). For those who are only interested in measurements, I've included an in-room frequency response and compression sweeps below. I am getting extension to under 9Hz in my room (the below plots start at 10Hz). I stopped after the top sweep as my UMIK-1 hit its factory limit and was clipping at that point. The subs remained clean with no unsettling noises other than the house sounding like it might fly apart, so I imagine that they still had more gas in the tank. Note that both subs are nearly 4 meters from the MLP and on a concrete slab. At that distance these subs manage to surpass 115dB at 10Hz. If this isn't enough low frequency output for you, PSA also offers an IPAL version (same cabinet) which includes a similar B&C driver with a larger motor, more excursion, as well as a more powerful amp. This should result in a 3-4dB increase in headroom sub-30Hz and beyond.
I have / have had several subs over the years, including Outlaw, Neumann, SVS, as well as the Hsus and Monoliths that I mentioned above. These PSAs offer the best performance out of any of them for both HT and music, and not by a small margin. For those who might be interested but worry over the lack of objective data, I'd suggest considering taking the leap. I am personally thrilled that I did. For those who want loads of unfettered ULF output from high-excursion drivers, yeah, sure, look at JTR, Harbottle, Funk, etc (at a much higher price point). For reasonably priced options that can deliver ridiculous SPL at practically all sub frequencies, PSA is certainly worth a look.
Frequency response after Audyssey XT32:
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Compression sweeps (UMIK-1 clipping during the top sweep):
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