Ok, my JL F112's are sold, so now I feel like I can make some observations about the differences between the Submersives and the F112's. (I was refraining because I had the F112's advertised on this forum, and I didn't want to make any remarks that a potential buyer might find "disparaging" about the F112's. In fact I have nothing at all "bad" to say about the F112's. I have had a thoroughly enjoyable ownership experience with those subs). Nonetheless, I have moved on to the Submersives.
First off, if you saw the pic I posted earlier, the Submersives are quite bit bigger than the JL's. I'll re-post the pic here for convenience:
The JL's were the best subs I had ever heard for music. I have quite a few SACD's and DVD-A's with some excellent bass recordings. I also have quite a few concert DVD's, HD-DVD's and BluRays. The JL's made the bass on those recordings sound more like *music* than anything else I've ever heard. I was actually very reluctant to sell them because I was afraid I would never be able to duplicate that sound quality.
However, their performance for Home Theater left something to be desired. I have a THX Ultra2 speaker system, (Atlantic Technology 8200e's, 3 of the L/R's up front behind an Acoustically Transparent screen, with SR's for surrounds). They are driven by an Earthquake Cinenova amp, (325 wpc into 8 ohms, 650 wpc into 4-ohms). The speakers and amps were definitely capable of full Reference Level... but the JL subs were holding them back. On scenes with really deep VLF effects, I couldn't get much above -15 to -12 before the subs would hit the "limiters", (and the limiters on the JL's are really obnoxious, with their "clacking" sound).
In my room, the dual JL's could hit about 100 dB before the limiters kicked in, unless the content had bass below about 30 Hz. Then the max output dropped as the frequency dropped. Some of the VLF bass spectaculars, like Pulse, Cloverfield, M&C, WotW, Ironman
etc., were not playable unless the MV was kept below -15.
I recently went to a friends' house to check out his theater. He's an AVS member, and he has a Klipsch THX Ultra2 speaker system with 4 Klipsch THX Ultra2 subs driven by a pair of the 1 kilowatt amps. His system is in a large, but fully sealed room. His system is easily capable of full RL at the seats, with headroom. I was floored by the sound, especially the bass. Right then and there, I decided I needed a subwoofer upgrade.
Enter the Submersives. Where the JL's were two 12" drivers in very small, sealed boxes, the Submersives are four 15" drivers in much larger sealed boxes. The JL drivers (probably) have more excursion (xMax) than the Seaton drivers. However the total air movement capability of four 15" drivers overwhelms the capability of two 12" drivers. Where the JL subs were moving like crazy to attempt to produce output, the four Seaton drivers are loafing along, barely breaking a sweat, producing the same, (and much more), output.
The resultant sound is...
...well, let's just say that the Submersives do everything the JL's did in terms of sound quality for music, (in fact, they provide the same sound quality at significantly higher SPL's), while at the same time, providing the massive output and extension I desired for Home Theater. Reference Level is now a piece of cake for my system, even with the bass spectacular's! In fact the system sounds like it has plenty of headroom left, even with the deepest LF soundtracks.
These Submersives are the best upgrade I have implemented in my system since I went with 3 identical front speakers behind an Acoustically Transparent screen. I have lost *nothing* in terms of sound quality and I have gained massive output capability and VLF externsion.
Mark Seaton, I couldn't be happier. Your subs have definitely taken my system to the next level. The whole system plays back louder, cleaner and "better" with your subs than it ever did with the dual JL F112's*.
*Having said all that, I don't want, in any way, to disparage the JL subs. I think, for what they are, (small, sealed, well built and executed subs), they have no peer. They simply have limitations. I wanted to go beyond those limitations, and the Submersives allowed me to do so.