@Landmonster
I know this has come up before.
What is the total open room volume you will be placing the subwoofers in? This is different than your "Listening Area." It should include all open hallways and any other room connections that are not closed off.
This is a very important metric which you seem to continually neglect.
You are clearly focused on the “impact” of the subs and like many don’t trust that even the 15" Rythmiks will be able to satisfy you.
This is fine. At some point, many of us (myself included) have questioned this.
While it will be nice to give you piece of mind in what will and will not pressurize the Whole Space, you also don't necessarily need to to have a good experience.
Regardless:
This article outlines our test procedure in determining a subwoofers room size recommendation based on its max CEA SPL output while making room size and subwoofer distance assumptions.
www.audioholics.com
This is an oldy but goody, and Shady will still reference the Bassholic rating when he does a Sub Review.
If you understand the CEA-2010 measurements, then you can compare and contrast Subs and how they stack up against each other. You can easily cross reference their output against subs that AH has reviewed to see how they stack up. Sources like DataBass, here, anywhere you see that testing.
The only catch is you need to make certain you know at what distance the testing was measured. Hsu, for example, publishes 1meter tests which will not compare directly to many other tests which are done at 2m. In order to properly compare, you need to subtract 9dB from Hsus measurements to compare to Shady's here at AH.
With those two bits to work with, you can easily start to make the informed decision you keep asking us to help with.
In the end, most of the Subs that get tossed about all perform more or less on par with each other. Some may have stronger output sub-20Hz, and less Mid Bass compared to others. These tradeoffs are routine, and you have to make the decision for yourself what is more important. Low Bass or Mid Bass, Small Box or Large Box, Higher than average output or not... Suffice it to say, you can not have all of those.
A good reference is Hoffman's Iron Law. When it comes to Speaker Design, you can pick any two of these three, but you can never have all three: Extension, Sensitivity, Size. The two you pick will cost you the third. Always.
Cheers!