I started to post about this yesterday, and then changed my mind and deleted my post. But, I think that the ported versus sealed issue deserves some more discussion. We seem to be concluding that a 2600^3 room is too small to benefit from ported subwoofers, and I'm not sure that is the right conclusion to reach. I know quite a few people, in similar size rooms, who prefer ported subwoofers to sealed. And, some of them are on suspended wood floors.
The reason that I mention suspended wood floors is because they convey much stronger low-bass tactile sensations (vibrations) than a concrete floor does. Mid-bass tactile sensations (chest punch) are primarily the result of sufficient SPL, combined with sudden percussive mid-bass sounds, such as a kick drum or a gunshot. The floor material is not really a factor for those sensations.
Low-bass tactile sensations, such as the rumble of an earthquake, or the thud of a T-Rex footfall, however, are primarily conveyed through the floor. And, ported subs seem to convey those sensations much better than sealed subs do. That is largely due to the dual action of the drivers, and the ports themselves, creating pressure waves at low frequencies.
Where I am going with this is that I believe that the right ported subs might add another dimension to the movie watching experience, when someone is on a concrete floor. That certainly seems to be the case for many of us. I like the idea of going with four Rythmik FV15HP's. I believe that the variable port tunes (including a 12Hz port tune) would give the OP great user adjustability and all the low-frequency extension he could ever want. And, there would be plenty of low-bass SPL, and the action of the ports, to provide some additional low-bass tactile response.
I don't believe that the FV15's would give up any significant advantage to the sealed versions in terms of accuracy or overall sound quality. And, although the Rythmik ported subwoofers do not create as powerful low-bass TR as some of the other brands of ported subs, they will provide appreciably more of that than their sealed counterparts. I think that might be very welcome for a number of action movies, where low-bass sounds can not easily be separated from low-bass tactile sensations.
Buying four good subwoofers to put in the corners of the room, as modeled by Nyal, means that the OP is unlikely to make a bad decision. There are probably any number of potential good decisions, in fact. But, I think that highly versatile ported subwoofers, such as the Rythmik FV15's, might be one of the best solutions. If at all possible, I recommend that the OP go somewhere to compare ported and sealed subwoofers (of whatever make) to determine whether low-bass tactile response is a potential factor in his preferences. For a 2600^3 room, on a concrete floor, I think that is a question worth exploring.
GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES
* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
Last edited by mthomas47; 10-12-2018 at 10:08 AM.