Is anyone thinking about building Walsh drivers?

I have been giving a lot of thought to this. I helped build the prototypes for the Walsh tweeter that Infinity used back in the '70's. If the cone was silver with a diamond "crosshatch" pattern (very early models) it was probably built on my kitchen table. That material was Reynolds "Diamond" aluminum foil that is probably no longer available. It was supported by 1 or so mil acetate, which thinking back was a bad idea.
I've started a thread on the DIY Audio forum to share my work towards building a semi-full range driver. I'm starting with the tweeter, since it is somewhat familiar territory, and a lot of folks out there have the old Infinity's who would like to get them working again.
Like the ill-fated Ohms, the materials used by Infinity to dampen the cones and terminate the traveling wave was very finite in it's useful life. Newer materials may offer better longevity.
Obviously it's going to take a lot of trial and error, but ultimately I'd like to think I can get something like the German Physik drivers for a lot less than 50 grand a pair.
J-

Mapman-
I'm surprised The new Ohm management hasn't jumped on this myself. Infinity crossed at 10KHz, much higher than the "new" Ohm's 8 KHz.. Ohm did license the tweeter to Infinity, but it was probably done during the old regime. Maybe they forgot. The Infinity seems to have gotten a measure of critical acclaim.
The high crossover point fits Ohm's current model, and the offers the advantage of being co-incident to the primary driver's axis. The Infinity had 4 crossover points, three of them in the critical presence band, and moreover it's location on top of a larger rectangular surface without a doubt caused numerous diffraction problems.
I have listened to both the old "A" and "F" models set up properly, and personally, I think that "stuffing a pillow" behind the driver as Ohm is presently doing is not the way to go.
As far as electronics go, you are preaching to the choir.

I can see your point concerning close wall spacing. The omni's need a lot of room to breathe, and creating the correct acoustical environment is black magic a lot of folks would just as soon avoid.
As for the tweeters, they take a lot of skilled labor to build. It's not something you can pop out of an injection mold, and the key to profits these days seems to be not paying craftsmen or worse, farming it out to the Pacific Rim.
One of the ESL companies, I believe it is Acoustat, moved their production from the UK to China to contain costs. The Chinese company immediately started selling a knock-off with a different name for about 1/3 the UK price. The Chinese seem to be very challenged when it come to intellectual property

Eldartford is 100% correct. In the "A", the cone was two tiered and had two angles. The different angles reflected the propagation velocity of Titanium (upper), and Aluminum (lower). I think the "F' was the first in a series of compromises, in that all three cone materials were all at the same angle.
The theory behind the transmission line was detailed in a White Paper that Ohm would mail you for the asking back in the "70's. I have never been able to find it on the web, nor have I been able to get it from Ohm.
We did some experiments with two way "Walsh" speakers back then using off the shelf 10" CTS woofers and the foil tweeter that Infinity later bought.
It didn't sound too bad, and in fact a couple of musicians and wealthy audiophiles were impressed enough to consider backing a commercial venture.
Unfortunately, a profitable business model and art for the sake of art collided immediately and the project was doomed.
A lot of effort was put into dampening/stiffening the cone with things like roofing tar, and terminating the outer surround to coax transmission line behavior at the same time keeping a "back wave" from going back up the cone.
One big problem was that the roofing tar worked for a week or so, but then it started to really harden the the character of the sound began to degrade. After the business deal fell through, we never followed up.
We never did any serious tests, because we were a couple of broke kids playing with Hi-Fi and couldn't afford the gear to test with. They sounded good for a while, though