I am working on a very compact horn subwoofer, which I am calling the "Crusher" horn, for the HL-10 woofer that should be good down to at least 55 Hz for a single box. I am trying to see how small of a mouth I can get away with, so that you have lots of little, easy to transport modules that can fit together for a huge, powerful bass stack, with the most output for the mouth area. My goal is to provide something I have heard mentioned on here a few times, where people wished there were a good horn subwoofer that was smaller and easier to transport, and that they would rather cart around 4 smaller subwoofers than two big LABs. Also, I am making sure it is relatively easy to build, with simple miter joints and easy-to-use openings into the rear chamber for access to the woofer. Small size is more important to me here than super low extension, though I won't settle for anything that won't reach 55 Hz. I expect to work more on it next week. If you're willing to wait a while, you should be rewarded. The goal is a sub that you can use anywhere from one per side (55Hz low frequency cutoff, -5dB) to 16 per side, and transport easily. I've already figured out how to fit over eight feet (97" in all) of horn behind my 15"x27" horn mouth (area: 405in^2) which makes up the entire front of the enclosure, which will be 34" deep. Unfortunately there won't be any handles but the box should be fairly small, and there will be casters on the rear so you just tip it up and roll it away. I'm making it a good deal smaller than the Punisher Horn, which uses a 12" Ciare woofer, so it will be even more attractive to people who might be considering the Punisher Horn. One limitation, however, is that the HL10 only handles 300w RMS instead of the Ciare 12.00SW's 1000w. The Punisher reportedly handled 1700w well. I might not have the chance for a while to build and test an actual Crusher horn unless someone is willing to buy and experiement with a HL-10 and report back to me how well the horn matches the simulation. The enclosure should be very relatively compact and easy to construct, especially with the lack of complex miter joints or routed holes and with the simplicity of the mounting of the access panel covers, so time and money invested should be very small.
One thing I need to know is what people want here. I have some concept drawings that are fairly advanced and about ready to go into Hornresp (the excellent program responsible for relative newbies like me breaking into the once-exclusive land of bass horn design). One thing I want to know is this: The current targeted bass cutoff is 55 Hz for a single box in half space. Would you have me try to go lower at the expense of sensitivity? Also, I'll have to see what Hornresp has to say, but the 97" horn of the Crusher is 1/4th the wavelength of 36 Hz. If the use of four or six of these boxes can get you down to 36 Hz, then that would be quite a thing to experience. However, it's been a while since I read up on horns, and I don't remember how mouth size affects the bass cutoff frequency. Guess I should do reading.
And if this turns out well, I intend to design the Super Crusher, designed around the LAB12, or perhaps the Adire DPL12 driver.