Originally Posted by DavidinGA
with a um18 that I am satisfied with overall for the low end, but I am looking to add some higher frequency mid-bass to my setup I'm not looking to necessarily increase spl, as the wife doesn't like the power levels I can get to already; just more 50hz-150hz thump.
More mid-bass means higher SPL.
or at the very-least, a more dynamic system in the higher frequencies, which is just a fancier way of saying louder.
So if your wife is unhappy now, she will be even less happy after the upgrade.
As for what to do. I'd definitely throw the Klipsch in the trash to make room for better DIY subwoofers.
You can power 8 PA460's with a single 3kDSP, or a UM-18 on one side and quad PA460's on the other.
I put 16 PA460's in two 20x20x80 sealed boxes powered with 8000watts RMS, dual octal-opposed, so it takes up very little floor space. Obviously that is triple your budget, but it has useable bass to ~5-10hz, and above 40hz it will literally kill a person (150db @ 1m); add the other 13 18/21/24"ers subs in my room + the remaining 92kW and it goes even-louder.
Each PA460 is about ~10db more efficient than a UM-18 or any other high-excursion HT sub.
Each PA460 with 500w has about as much mid-bass as roughly 4 LMS-18's with 16kW.
Mid-bass is mostly limited by total cone area. (Heck, all bass is...
Two PA460's is a good-start, but 4 or 8 would be MUCH better, in terms of being kicked in the head.