I heard a Leak loudspeaker with a "sandwich" cone woofer in 1971---it was excellent, the best speaker I had heard until hearing my first ESL later in the year. That year I also heard the ESS Transtatic I, which had three RTR ESL tweeters and the legendary (with good reason) KEF B139 woofer, itself having a sandwich cone with a flat front face of Styrofoam and a butyl surround. I currently own a pair of the Transtatics, and their B139’s are still operating perfectly, as are the KEF 5" B110 Bextrene midrange drivers (the first commercially available Bextrene-coned driver) and the RTR tweeters.
I’m a big fan of composite construction, @bdp24 , from Focal’s W, to Rohacell to ... paper! :)
I’m currently listening to Scanspeak’s Revelator mid-woofers, which are two paper layers with an epoxy bonding them together. really pretty marvelous.
The "aged cheese" woofer never caught on, neither did the overly damped "used catcher's mitt" design...I say stick with paper...or hemp fibre...anything...
They should have just followed Peter Walker's lead. KLH?
I believe Lowther still uses a paper cone. Great sounding speaker if set up right.
My Audionote AN-J's have a nice paper 8" woofer and sounds great to me!
Bozak has it was rumored beaver felt in the tapered cones
the Eagles have never sounded better than the B-305 ( half a Concert Grand ) circa 1965
We of course being a KEF and KEF-Kits dealer had access to drivers, filters, cabinet designs, etc
i goofed around w Cantata, 104 a/b ( a B200 driving a passive 139, which I recall was ok...
the lovely and sweet T-27 or T-33
with a Decca Ribbon
ah the fun
We also had an FFT running on a Commodore PET
you understand the Vandersteen and Thiel..... or maybe not....,
In the late 70’s I had a prospective employer tell me that COBOL was dead.
So much for predictions. 😊
"We of course being a KEF and KEF-Kits dealer..."
Do KEF kits still exist? They used to be an interesting concept. A friend of mine built a pair and they sounded really good. For that time and to me, at least. Model 102? 103? 104? or am I mixing something up?
Do KEF kits still exist?
Not for a very long time, but you never know when some one will find a NOS kit in their garage and sell it on ebay. Not that I'd buy one, age will do a lot to a driver, but hey, lots of great kits from Maidsound, Meniscus and Parts Express are available for peanuts.
Had a pair of Leak Sandwich speakers . Very good sounding on low watt tube amps. Look them up. IIRC foil and styrofoam? Sorry about no paper ref.
bdp24 noted your comment on the KEF B139,
I finally bought commercial speakers, (Monitor Audios) and decommissioned my homemade KEF speakers.
Have to say the B110 (dextrene?) I think still sound fantastic.
I`m making small subwoofer boxes for the B139s,still going strong after 35 years!
@lastperfectdaymusic, the ESS Transtatic put the KEF B139 in a transmissionline enclosure (hence the "trans" part of the name; the "static" for the RTR electrostatic tweeters). That enclosure was very similar to that of the IMF Monitor, which also had a B139 woofer. Irving Fried (IMF were his initials) was a fan of transmissionlines.
Interesting that on both pair of Frieds I had in the 80s-90s it was the paper cones that eventually failed.