Mid-woofer for foldy-twisty horn?

[Spasticteapot]

I was looking at building a pair of these funky horn-loaded speakers.

http://www3.ocn.ne.jp/~hanbei/eng-angular.html

While I'm not so keen on "fullrange" designs, I think that this is a pretty neat trick for squasing a great big horn into a nice, neat rectangular tower speaker. Use a standard woofer and add the tweeter of your choice (perhaps a Bohlender-Graebner Neo3?) and you have above-average bass response with a small, hopefully inexpensive mid-woofer.

Two possibilities are the Silver Flute W14RC25-04 5.25" and W17RC38-04 6.5" woofers, with a Qts of .28 and .24, respectively. Zaph very much liked the W14 driver, at at $17.50 or $24.60, they're both inexpensive drivers.

http://madisound.com/silverflute.html

While the Qts is a little on the high side, I'm leaning towards the W14RC25 simply because it's cheap. Horn-loading may help push bass response closer to the Fs of 42hz, and while this driver is never going to rival a 8" woofer for sheer floor-stomping bass, it should sound very nice with a good tweeter.

With a suitably inexpensive tweeter (perhaps a cheap Hi-Vi or Sinar Baja dome?), these could take the crown for "Best speaker under $50 using parts that you can actually get from Madisound."

(It's pretty hard to compete with homemade scrap-parts electrostats or NSB line arrays!)

For a more "high-end" design, the W20RC38-04 might work very well - it's an 8" driver with a Qts of .232, and it only costs $32 to boot! However, they don't like to cross over at 1khz or higher, or so I have heard.

However, there's an easy solution: The bohlender-graebner Neo3 tweeter and Neo8 midrange combo. It's capable of crossing over at 700hz, and the sensitivity is almost identical to that of the woofer.

Alternately, the PDR versions of the midrange and tweeter could be used. While I would prefer to use this tweeter due to the much better off-axis dispersion, the sensitivity is much lower, at only 90.5db. While this matches the 8-ohm variant of the W20, the problem is that the W20 is an 8-ohm woofer and the Neo drivers are 4-ohm - I'm not so sure if this would work, but if it would, it's an even better option.

[Pano]

You know Spastic, I've been looking at that site for years. Hard to find anyone in the West who had built any. Maybe someone here has?

It's a fun idea, anyhow.

[johninCR]

I seem to remember that Mr. Takenaka (mr. spiral horn) prefers higher Q drivers in his cabs. His new staircase construction method seem like a very easy build, although it would seem to be a compromise compared to the continuous expansion of his original spirals. I'd like to see some large acrylic versions of the spirals for use as BR ports, since that would have some advantages, especially to add some resistance to avoid completely unloading below tuning.

[Ang]

can anyone comment on the quality of the bass from these vs TL designs? I'm looking to crossover an 8" driver around 1K and I want excellent sensitivty and extension (not hard to please, am I?). So.... I was looking at the helical designs which seem to be more efficient vs tl's.

Does anyone have any advice for other driver's that would be ideal for this? Part of what I'm wondering it if I mount this driver @ the bottome of the tube for stability, will that be a problem when it's playing so high?