Here are two sub set-ups for around the same price using the same sub(s) that would work with 15A. You could also use the same set-ups with smaller enclousures (5cf) with the AV15H subs.
Option #1 - AV15X sub, $275 w S/H
AE 2 x 18-2100 PR's, $250 w S/H
ED LT 1300 amp, $450
ED EQ2 or Behringer EQ, $100
Birch ply, 2PCS, 4' x 8', $100
Other supplies such as glue, screws, paint, stuffing, etc., $100
Also, a EP2500/4000 amp could be used for $100 less.
Option #2 - Same as above except it would substitute the PR's with two
AV15X subs in a opposite built sealed box for $50 more. So
option #1 would be $1,275 and option #2 would be $1,325.
Both set-ups would go in a 7cf enclousure, with the tuning of the PR's sub at 16hz + 1,300 watts input and the dual sub set-up getting some 650watts per driver. I believe the dual drivers would need to be built dual 8ohms in order to give the amp a 4ohm load. Here are the graph readings I got from AE (within +/- 1db);
Option #1 Option #2
Frequency AV15X sub w/PR's AV15X dual sealed subs
15 110db's 103.5db's
20 114.6db's 108db's
30 117db's 114db's
40 118.4db's 117.5db's
50 119.3db's 119.5db's
60 120db's 120.5db's
70 120.3db's 121db's
80 120.6db's 121.5db's
90 120.8db's 121.75db's
100 121db's 122db's
I have option #1, but I almost went with option #2. Why? Well, my room is 6,000cf and I wanted a flat frequency response from 15-20hz to 100hz, which I got with the very little room gain I got. Which set-up is best? It depends on your low/mid-bass and linearity preferences, room gain, etc. I do think the AV15X dual sealed subs should be close to the Submersive sub, performance wise.