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."
Many years ago I worked for an ESS dealer. I was impressed with the the ESS speakers at that time. Amazingly clear highs, really good bass for their size. The Heil air-motion transformer reminds me very much of a good ribbon tweeter. It would be fun to compare them to my current speakers.
Back in the mid-1970's, I worked for a high-end audio dealer in Seattle named ElectriCraft (long since defunct) which carried the ESS / Heil speakers. They produced very good sound for their time, but were VERY inefficient. To get loud SPL's from them, we used the PhaseLinear amp (Bob Carver's first commercially successful power amp, which was affectionately known as the "FlameLinear" for its tendency to overheat and "flame out"). The PhaseLinear amp produced 300-350 wpc (immense power output for that time), and it had barely enough power to drive the Heils to high volume levels.
It has been quite a while since I've heard the original ESS AMT speaker. I recall that the Heil driver sounded quite good, but the bass response did not match up.

At this year's THE SHOW (next door to CES) I heard a current version of a speaker with the Heil driver and it sounded pretty good for the money. The technology is still alive.
purchased a pair of Heil air-motion transformers from ESS a year and a half ago after hearing a pair of AMT's.
love 'em.
driving them with ASL WAV 8's (highs) with audire planar IV (mids) and cerriano subs, with two active 3-way mono crossovers.
still available from ESS for a desent price, even though ebay gets some outrageous bidding on old beatup units with questionable diaphram quality. kurt
i bought a pair back in 1978. used them for years and I liked them very much up until the early 90's. i recently sold them (been in my closet for many years) 5 months ago for $250.
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!
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
My first "real" stereo, back in 1975, was a system with SAE pre-amp & amp, with ESS AMT-1a bookshelf speakers. I really liked them. As with most of them, the foam eventually deteriorated & fell apart in the late 80's.
I have been a stubborn fan of ESS speakers since I first heard, and then bought them, back in 1974. I have long felt, like others have mentioned, that the bass and low mids could be better, but I would not give up on the transients that the Heils can produce.
After a long search for a speaker builder, I was finally able to have my AMT 1 Towers rebuilt, earlier this year. We replaced the old paper drivers with new kevlar mid woofers, and he designed and built completely new crossovers. I also use a subwoofer and an external digital crossover to help extend the lows. Well, I now own the best sounding pair of speakers that I have ever heard. We will be teaming up again, this time to build a speaker system from scratch. We will be using the Heil as the tweeter, in a bi-amped system, with a powered sub(s). I could never find a speaker company that used the Heils to their full potential, so with these two projects, we are building our own.
Thought I'd revive this thread.

I'm now in the process of rehabbing a pair of ESS AMT 1 (transmission line) Towers and was wondering why there is nothing in the A'gon blue book. Certainly in the last 5 years some have sold on the 'gon!

ESS is now active and actually never went out of business. They still have the originaly ownership and I've been chatting with the President of ESS, Rico. If I heard him correctly the owner simply put the business into retirement until deciding to bring the brand back into production.

They're going to have 2 rooms at CES, one devoted to a very large scale HT system. Legacy products are being serviced, many from NOS parts. Apparently crossover rebuilds are popular for the larger AMT 1 models.

Any ESS folks out there? Thoughts?
I have several pairs of Heil AMT-1 tweeters. I've had a pair on a 3 way system with Altec 416-8Bs, Altec 311-60 horns and Altec 288 drivers for almost two years. They easily keep up to the large Altecs, with head room, and they sound clear and musical. I love them.
wow, you guys have photographic memories. i had a pair 35 years ago and loved them. i would really like to hear them now on some good gear. i was using a crown d-150 and a sae preamp. probably a thorens td-160 or bang and o 3000 table. later i was a rep for the heil tweeters and sold them almost exclusively to pro music shops. they loved them. big dudes in kansas city was a retailer i remember well.
Lafayette branded Ess/heil speakers were my first good speakers circa 1977.

FWIW, they did not stick around long. The heils continuously got fried and the bass was fat/muddy. Not sure the heils were really that well integrated into the overall design.

I realized their shortcomings a few months after getting them when I left my summer job at Lafayette and worked part time at TEch Hifi during college years.
Very familiar with the Heil AMTT, built quite a few speakers using them during the late 70's right up until 1990 when i could no longer get the units.

Never cared for the ESS version, Very good driver and a Pity they ( ESS) never went into production with the full range version...

I had a pair in the late 80's (bought them used then).
I had to get the woofer surrounds replaced. Other than that, I was very pleased with them. The tweeter was spectacular in its day.
I just bought a pair of ess amt 1b, and like them so much. The only concern is the high is a little grainy. Any thought? If you are having the same model, where do you set the mid and high adjustment? Thanks
I had a pair of what I recall being ESS Heil AMT speakers: about four feet tall with a removable cover for the top. I thought they sounded very good driven by my Marantz Model 18 receiver. It was when I got the notion of using them with my TV that things went awry. Even having the speakers in the same room with the TV caused distortion of the picture that required deGaussing. IIRC the period of use was late 60s to late 80s.

Had a bookshelf pair around 1978 to 85, with a rear passive driver to augment the 8" bass on the front. The Heil tweeter is very efficient and clear sounding, great for dull LPs and cassettes of that era. The woofer is flabby but can play very loud, great for parties. It can compete very well with the huge Altec Lansing or JBL of that decade.
Adam Audio from Germany is using a variant of the Heil in its' speakers.

I'm very interested in anyone's direct experience with this company specifically the Tensor series.
I just encountered a new speaker company, GoldenEar Technology, that features its own nicely refined take on the Heil throughout its product line.

The company's founder and chief designer is Sandy Gross, who was a co-founder of Polk Audio in 1972 and Definitive Technology around 1990. You can especially see some family resemblance between GoldenEar's Triton 2 Tower and the Def Tech Mythos, but the GoldenEar uses the new Heil tweeter and costs 40% less than the Mythos.

I heard them at a high end audio open house at my local high end store just a couple weeks ago. Co-founders Sandy Gross and Don Givogue introduced the speakers while Stereophile's John Atkinson played 24/96 digital masters from his laptop. At $2500/pair list these speakers are stupid good and neutral. Bass extension goes down to a claimed 18Hz thanks to each speaker having a 1200 watt built-in amp to drive twin 5x9 bass drivers assisted by even larger passive radiators. It makes amp matching much easier.

The front baffle is only 5" wide, so imaging and soundstage are particularly good. They also make a selection of L-C-R and surround speakers featuring their "folded ribbon" tweeter in a D'Appolito array.
Just listened to Billy Joel At Shea Stadium Blu-Ray on my pair of AMT 1-D's. The cymbals sounded like a real cymbals with nice bite and smooth decay. The drums sounded deep and, amazingly, didn't overhand by mid-bass bloat. I go a long time without listening to these and with a truly good recording they really still can impress me. Recordings with too much bass, especially sludge-like mid-bass bloat, sound bad no matter how good the mids and highs are.
To my ear, there was always a speed differential making for poor 'blending' of the woof--an annoying discontinuity.

Good listening.
In response to Bill's post, I have heard the Adam speakers on one occasion, the $10K stand-mounted one with the powered woofers and the Heil type midrange and tweeter (I believe it is the smallest model in the Tensor series), and was extremely impressed. I was prepared for what Larry describes, but at least on first listen to me Adam seems to have done a great job, at least in this model, in minimizing that discontinuity between the midrange and the woofers. I had come in to my dealer's to hear the Wilson Sashas, which did sound very good, but the Adams had a dynamic realism to them, especially with transients, that made them sound like a live musical event vs. the Wilsons which, good as they were, sounded more like speakers reproducing a live event in comparison. I would like to listen to the Adams more to see how good they are in long-term listening, and perhaps also to the larger model in the line with deeper bass response to see if adding the last octave of bass to the speaker might highlight any discontinuity between the woofers and that remarkable performance in the midrange and treble. It could be that my enthusiasm for the dynamic realism of the speaker and the open and clean sound of the Heil drivers caused me to overlook some flaws in the speaker that ultimately might make it something I couldn't live with, but for now they are definitely a speaker that I would consider on my short list for purchasing.
I've always wondered why the AMT design did not get more attention over the years,with more designs showing them.Maybe a legal thing?

I owned the AMT Rock Monitors back in the early seventies.Sheesh,could these rock out,and with detail to spare.Those were interesting times.

No speaker of the time could do the Doobie Brothers with such dynamic aplomb and airy detail,but of course the fact that my pals were actually "doing doobies" in my room could have affected my senses -:)

Best to all
Lrsky, I identified this same problem with the two way. For me, the 3D sound of the tweeter was too good to pass up; so good, that I built 3way speakers using the ESS Heil air-motion transformer. With the help of an engineer to design the crossover, and a lot of experimentation with drivers; I got a smooth blend that is absolutely fantastic. Not recommended, too difficult.
Reprince, while my speakers sound fantastic, they are "but ugly" and I don't intend to hire a cabinet maker. I would like to audition the Adams speaker, post any information.
I just modified my ESS HEIL 1D and it is 3 times better then the original and is by far the best and most liveliest loudspeaker I have encountered among all loudspeakers I own and have heard and unfortunately I haven't heard many other fine systems.
I added another ess heil 1c transducer separating it from the 1d about 8 inches on top of it using longer screw poles and using a square mesh type square metal frame to place the 1c on top of it. I removed the front 12 inch ess driver and placed it on the REAR, removing the passive radiator and ordered the new ESS 12 inch driver from parts express. I placed that on the front. Now I have a DIPOLAR bass system and the upper highs and mids are done by the ESS HEIL 1C and 1D in a linesource array. I also added the controversial dakiom stabilzers in the crossover to clean up any harsh signal coming from the amplifier. I use paxthon integrate tube amp and a grand fidelity tube cd player and the soundstage is amazing. Modifying the ESS HEIL the way I did puts it another level of performance the original design was unable to do. Everything is wider and bigger. The bass are much tighter and realistic and deeper. The vocals and instruments are as if the musicians are actually there.

If you can afford to add additional ESS heil drivers and woofers, I highly recommend it for you DIY ess enthusiasts.

I collect loudspeakers and I have magnepans, acoustats, eminent techs, klipsch, sls and ohm walsh and by far the ess heils being modded puts me in audio nirvana. I am completely satisified with this set up!
Armyscout41 that sounds like a travesty of a design. Mounting another active bass driver in a location designed for a radiator is subjecting bass response to severe wave cancellation at all levels of the audible band. There is a significant reason the radiator is in place. The cabinet volume (vb) is specifically designed to have the active driver behave and perform to it's potential which is inclusive of the reflex alignment of the accompanying radiator. What you're suggesting is that bass has improved and that just cannot be so. Adding additional amt drivers to the array of only a single, yet again defeats the ability of a single woofer to perform in a somewhat congruous nature with an air-motion transformer.
Lawrence Audio Cellos use the Heil for the Treble and Midrange. They are extremely good!! They are relatively unknown here in the states. They have a nice website and will shortly be reviewed. I have no affiliation and just had the opportunity to hear one of the few pairs in the US.

It just so happens I have a pair of ESS MT with Optional
sub-woofer bass cabinet the made for the ESS main cab
FITS into.
I Bought ALL NEW BACK IN THE DAY!!Late 70's
The sub woofer is a KEF Rectangular 6 X 12" floor firing.
It's set-up for Tri Amp operation only.

How good are they? 15+ years back. I hauled them to buddy home who had just bought a pair of Sound Labs Electro's

Their were (4) of us. We did blind. TEST both were hooked
to ARC-D150M (Mid to Highs.)(2) ARC 120 for mid-bass & woofer on my EES MK11 all thru ARC-SP15-2 Pre-amp. Test record was a Telarc: Grand Canyon Suite. THE TEST(4) chairs turn backs to speakers. His wife JOB turned the balance L to R as the Pre was in Mono, playe SAME 15-SEC track over/over. We all wrote down. L is better. or R is 5 plays.
3 of the 4 picked the ESS for best upper Mid range to Highs.
All 4 including myself picked the S-Labs detail in lower Mids to upper bass hands down. But the EES SUB had punch all could feel the standing wave on our backs.

No of us were told which speaker was L or R.
Hope that helps your question.


I recently came across this brand. Looks like high efficiency loudspeakers. Any comparisons or experiences?
They came out with some headphones that uses these Heil air-motion tranformers, the new Obravo HAMT-1's for $1500 that sound as good as.. Reference Floorstanding Speakers!!
Recall that I heard Born to Run all the way thru for first time on a pair of AMT 1 B with a B&O table, Apt Holman Pre and this day trying to get that ROCK sound..ha
...the memory..altered..of youth is a great thing.....
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.