Before ESS introduced the Heil AMT, they already had a line of really good speakers using KEF drivers. The way Dr. Heil and ESS hooked up was that the Doctor came into the ESS dealer in San Jose (TV-Audio Center, Inc. I was a customer of theirs.) to see about getting a pair of KEF B-139 woofers (the 9" X 12" flat-faced oval driver you may have seen pictures of) to use in the speaker he was developing (the AMT, of course.). ESS was using the B-139 in their Transtatic model speaker (Dave Wilson used it as well, in his WAMM loudspeaker. It's a REALLY good woofer.), along with a KEF Bextrene 5" midrange driver and a trio of RTR electrostatic tweeters. The Transtatic was actually a much better speaker than the Heil AMT, but cost $1200 in 1971 dollars. It was competition to the Infinity Servo-Static loudspeaker. I found a pair in the early '80's, one of them having a replacement woofer. I called ESS in Sacramento and got their last remaining B-139! Still have the speakers.
ESS and Heil air-motion tranformer - any thoughts?
These seem like interesting speakers, has anyone on this board had any experience with the ESS line of speakers?
A.M.T. description:
"The Heil diaphragm, made of soft, quiet mylar to reduce background noise, is bonded with conductive aluminum strips. It is equivalent in surface area to a conventional cone type eight inch midrange driver, but is accordion-folded down to a compact one-inch band for better point source dispersion. The low mass diaphragm is suspended in a massive magnet structure concentrating an intense magnetic field around the diaphragm.
When a signal passes through the aluminum strips, the bellows-like motion of the folded "pleats" squeezes air out five times faster then the air motion of a conventional cone driver. The virtual "instant acceleration" provides high definition, crisp transients, and overall spaciousness with superb dynamic range. This type of performance distinguishes the heil from all other transducers."
http://www.essspeakers.com/
A.M.T. description:
"The Heil diaphragm, made of soft, quiet mylar to reduce background noise, is bonded with conductive aluminum strips. It is equivalent in surface area to a conventional cone type eight inch midrange driver, but is accordion-folded down to a compact one-inch band for better point source dispersion. The low mass diaphragm is suspended in a massive magnet structure concentrating an intense magnetic field around the diaphragm.
When a signal passes through the aluminum strips, the bellows-like motion of the folded "pleats" squeezes air out five times faster then the air motion of a conventional cone driver. The virtual "instant acceleration" provides high definition, crisp transients, and overall spaciousness with superb dynamic range. This type of performance distinguishes the heil from all other transducers."
http://www.essspeakers.com/