Welcome aboard. Recently all the audio competitions/shows in New England can be found at nadbl.org which is rebranded TNESPL and has pretty much merged with New England SPL, though it may be that Steve will continue to update events on New England SPL website.
My .02 cents on your philosophy: Low inductance isn't necessarily the end all be all of good sound. AFAIK there's more than one way to skin a cat there. Split gap, split coil, LMS coil are other popular distortion lowering x-max raising techniques and even underhung motors seem to do quite well. Shorting rings aren't new and have their place but from the debates I've seen on the subject have their own set of tradeoffs.
As others have mentioned, single 4 ohm coil is a hard sell in the 12V arena these days. I suspect a brick and mortar with a real salesman could sell single 4 ohm, but we are living in the age of the cheap class D Korean amp. Power can be had for 15 cents a watt and you want to build your 1 ohm stable amp robust enough to survive .5 ohm since every ******* who watches youtube is going to try it. Even amps that make max power at 2 ohm are rather rare these days, I expect largely due to the cost We're not going back to bulky and hot-running class A/B for sub amps for the sake of driving 4 ohm loads. The psychology is "I want to get every bit of power out of this amp" and virtually nobody buys a 4000W@ 1 ohm amp to run it for 1000W at 4 ohm with better damping factor and sound quality.
In the single 4 ohm arena the market is pretty much home theater/Parts Express/Madisound type crowd. You might find some high voltage guys at
DIYMA forum but even there I suspect 1 ohm class D is or will soon be replacing that.
Also be very careful about 1200W power handling claim. If you call that "recommended amp size rating" you will probably be safe, but I'm very confident if you clamp a 50hz sine wave into one of those subs and clamp 1200W of power into it it will smoke quickly. Don't think that's realistic for real-world? Come to some of the SPL shows and see what passes for "music" and see what people who buy power cheap do with woofers.
Anyway, if you really wanted to sell something to the guys who like to run higher impedance, you'd do better to figure out a way to make an affordable amp that makes 1000W at 4 ohm with good enough protection to prevent guys from dropping it down to 1 ohm nominal counting on "rise" to get back up to 4.
Again, welcome aboard, it's good to have another enthusiast in the area and on this forum.
