ESS and Heil air-motion tranformer - any thoughts?

I have a pair of them in my family room, in the corners. They're my father's, and that's what the conventional wisdom of the day told one to place the speakers. The woofers are now suffering from rotted foam, for the second time. He bought some woofers to drop in there this summer. It will be interesting to give them a listen once he fixes them. My recollection was that some of the midrange and maybe all of the treble sounded very, very good. But, I have not listened to them in yeeeeearrrrrsss.

Still have my AMT-3's ("RockMonitors") from the 1973/74 time frame. Their configuration consisted of the Air Motion Transformer, a 5" mid range and (2) 10" drivers.

Up until a few years ago, they were used in a HT system, but are currently in my son's seldom played, and never critically, 2nd.system.

The 10" drivers were re-coned twice, and then totally replaced.

If someone knew their way around speaker design, replacing the crossover and the (3) drivers with "matched" ones, would probably substantially improve a so-so speaker.

The lack of synergy between the standard drivers and the Transformer were the speaker's weakness, but in the 70's, when loud was good, and louder was better, the AMT's driven by a Phase Linear 400 were a lot of fun.

BTW, I still am using the 1978 Phase Linear Model 400 Series II to drive rear channels in a 7.1 HT set-up.

trelja- you don't have to replace the woofers- which can hurt the sound if it's the wrong woofer for the cabinet (Q factor) - you can re-foam what you have!
http://www.simplyspeakers.com/2doityourself.htm

I had a pair of ESS amt-1a bookshelf speakers for about 25 years. In October 2003 I replaced them with a pair of Paradigm Studio 40 v.3's. The ESS had plenty of high end and bass. When I had them I thought the high end was clear. The Paradigm's are far clearer. The bass in the ESS is mushy. The Paradigm has a better punch. When it comes to midrange I feel there is no comparison. The Paradigm's are far superior.

Back in the '70s Ess released the AMT-1 speaker. I own it's predecessor the Ess Transsatic. The TS uses a Kef 12x9 flat piston driver in a four foot long floor ported transmission line woofer. The mid-range is handled by a Peerless 5in polypropalene cone driver in a short rear firing transmission line. The tweeters were 3 RTR ESR-6 electrostatic drivers, one mounted horizontally above the mid-range, two more mounted vertically below the mid-range. This speaker is the best sounding speaker I've ever heard. The bass is crisp, taut and very deep. Reference 2001's low D organ opening of "Also Sprach Zarathustra" or the bass riff in Stevie Wonder's "Superstition". The highs are clear, sweet and shimmer transparently on the most difficult to reproduce instruments. Find any well recorded piece containing triangle strikes. Response is dead flat from 20 to 30K Hz. The speaker combined transmission lines and electrostatic tweeters hence "Transstatic". It's sonic strength was offset by the weakness of the RTR ESR-6's. They find any number of ways to self-destruct, from arcing grids to just losing thier ability to respond to the high voltages required to drive them.

The Heil based speaker was released immediately after Ess ceased production of the Transstatic. To my ear comparing the two speakers the AMT-1's bass was weak and muddy. The mid's and in particular the highs sounded screechy and strained, but then my ear may have been spoiled.

I still have my Transstatics if anyone knows how I can get my hands on some RTR ESL-6 drivers please write.

Thanks, Jim Miller