Wayne Parham Messages: 18752 Registered: January 2001
Illuminati (33rd Degree)
Looks like you're having fun. Nice stuff!
The midhorn I use in the six π and seven π cornerhorns will get you down below 200Hz if used in corners, but it won't go that low out in the open. It's designed for home hifi use, where it blends with a woofer in the 100Hz to 200Hz range. The corners help, acting sort of like mouth extensions, because the midhorn is tucked into the corner so close to the side walls. Without corners, the mouth area is insufficient for output below about 250Hz. You'd need a larger horn for that.
I'd grab a copy of Hornresp and start playing with it. You can probably knock out a few models that look good in a short period of time. Myself, I'd prefer a straight horn rather than folded for use in the midrange. Folded horns are great below 100Hz, but once you're in midrange territory, I don't like them. Wavelengths are too short and you inevitably run into problems with standing waves.
Here are Hornresp models of a couple larger midbass / midrange horns I tinkered with a few years back: