Very nice work. One thing I've always wondered about is a wide-bander in a flow resistance enclosure, rather than a horn or traditional box type setup. Has anybody ever tried that? In theory at least, no crossover combined with the room nullifying effects of a FR enclosure with maybe a bit of EQ would be the best of all worlds, requiring little more than maybe a few corner traps where the FR effect doesn't work.

What I was thinking is something like an Omega Super 6 that would run full range from about 45ish Hz to 18Khz, in a flow resistance box to cancel out the side and rear wave. Two subs I guess with some bass traps or EQ or both could be used to fill in the bass response where FR enclosures don't work anyway. The one FR speaker I'm familiar with is the Krypton, which is a 3-way, with two 8" mid-woofers that work from 160-1200Hz. I don't know how much bass output the Super 6 would lose if the box was a FR instead of just ported.

I suppose one possibility would be two opt for a two-way setup, using a method like Reference 3A where the mid-bass driver is driven without a crossover, with a single cap acting as a high-pass filter.

SYSTEM UPDATE:

BTW, on a related thought... I realized how dumb it was for me to notch the 30Hz room mode on the subwoofer DSP unit rather than in JRiver (where the EQ also affects the mains.) I have now implemented the 30Hz room resonance notch in JRiver. This also relieves the 6' Fostex drivers from trying to reproduce bass notes it couldn't reproduce in the first place (I'm sure the little driver was playing 60Hz and 90Hz tones - 2nd and 3rd order distortion - instead of 30Hz.) This seemed to have made a huge difference in the clarity of the driver and eliminated some odd noises from the horn (the horn is tuned to 50Hz, and the driver Fs is at 50Hz).

I tried doing the same with the 55Hz room mode, but in the end, I've decided to still let the mains handle it for better mains and sub integration. This may change once I get a better subwoofer in because the Hsu is not exactly a tight sounding sub.

I'll summon Donald to see if he can answer some questions. Woofers in open baffles are almost always EQ'd to adjust for the roll-off. Given the size (18') and excursion capabilities (max 75mm p2p) of that Aurasound monstrosity, the EQ requirements would be less extreme. The Qts .45 of that woofer (if it is the NS18-992-4A) would lend itself to an open baffle design as well. I wonder if the compensation circuits are part of that tube AXO box.