I first heard the ESS AMT-1B while stationed in Okinawa Japan. I compared the ESS to Bose 901s the low frequency response just was not there. I heard the speakers with top of line equipment at the time SAE amplifiers, Marantz 400 Watts. Fortunately we could bring albums and reel to reel recordings to the audio liseting room and mix an match components for one of the best true listening experiences. To bad food and drink was not allowed. I brought in a 10 inch reel to reel recording of various musicians, music formats from jazz, classical, R&B and classic rock from the era and spent an afternoon comparing all the equipment available at my fingertips. To this day, for the price range $800.00 I have not heard a better sounding speaker. I bought my second pair on line and reconed the speaker and passive radiator.

With lots of headroom a powerful amplifiers two Crown Comm-Tech 800 and Adcom GFP-1A preamplifier. I have a Sony TTS-3000 Turntable amzaing paid $60.00 at a vintage audio replay with Shure V cartridge.

The speakers provide surperb midrange and high ends are clean, crisp and clear. The speaker and passive radiator adds a nice punch to the lower frequencies with adequate response. I have two ADC SS-II equalizers totaling 24 frequencies to tailor the sound to my speakers.

The original ESS AMT-1B I have had the all speakers surfaces reconed, better than factory specifications (Go ATC Audio West Springfield, MA). I replaced the speaker tops with 1D models. I also placed felt pieces on each of the corners for a better fit, especially at high wattage. I am driving the ESS-1B with two Crown CommTech 800 amplifiers. I have two sets of speakers downstairs in my listening area.
I listen to this day with my Akai 635D reel to reel, put to same an CD produced over the past 10 years.

I recently applied new veneers to all four speakers and tops. Would not recommend that to the weekend carpenter. I matched all the veeneers on each side on the speakers and speaker tops. Applied tung oil and every week use lemon oil to protect the veneer and clean the speakers.

The only drawback is the footprint of the speaker. An advantage is the speaker can be placed within 3 inches of back wall.

I am still a huge tube amplifier advocate. Can not beat that warm rich sound from a amplifier. Some day will be able to buy Big Blue McIntosh amplifers, (last thing my better half wants to hear.

Bottom line: ESS AMT-1B/C models for the price range, to date have not heard a better sounding speaker. Keep in mind with high end equipment your listening experience will be enhanced dramatically. I only crank up the system when the kids are and wife are gone. My neighbor accross the street who is a drummer professionaly, enjoy hearing music filter his way.

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All in all the old style of these cabinets does not suit modern decor. When people see my speakers they think i just popped out of the 70's. While i do not really agree, it's a common theme amongst all who see them. They truly are a sweet spot in my house listening wise. The new cabinets now for sale haven't changed at all i noticed. Too bad the company can't redesign anything from 35 years ago as they currently only offer this style of cabinet. Good old sound from good old speakers never hurt me one bit and i wouldn't personally trade them in for newer speakers but i wish something else was offered so i do a side by side comparison and look at possibly trading up "style" without trading in sound.

When I was 17 in 1976 I figured the best way for me to get credit was to take out a $2000 loan for a stereo. (had a car) I spent 3 months studying specs. Output, response, harmonic distortion....And listening. I heard a pair of amt1b's in the first store I went to. Didn't care for the sound. I listened to Klipsch, Altec's, Bose, all the top ,most expensive speakers around then. They all sounded great but something was missing. I went back to the first store. I told the guy I wanted to hear the ESS's again. The top end was more crisp and real as I had ever heard but not enough bass. The salesman finally ran those 75lb bass magnets up to 1/2 and that was all it took. He'd had the bass off. The pair I bought were used by the "Stones" in their studio..paid $500 apiece. Picked up a perfectly matched Onkyo 100watt per channel TX6500. Best 2 grand I have ever spent!!!!! Still rocking the neighborhood to this day!

I agree the people who enjoy the ess heil. I don't agree with any of the critics. These are the most lifelike loudspeaker I have ever encountered and I am a loudspeaker collector from electrostats to planars and dynamics. For anyone to say these aren't accurate, they need their ears checked. For anyone to think they knew more then the late physicist dr oskar heil who will claim themselves as audiophiles are a joke. what he invented was definitely revolutionary. I thought ribbons were accurate and until I heard the heils, it's in another level. Don't even think that the crappy dome design can even match these heils you would be out of your mind. Modifying the ESS makes it even many times better. I have an AMT 1D on steroids. I have two ess 12 inch woofers firing on both sides with no radiator. I decided to place 3 ess heils on a line array or linesource design and using dakiom feedback stabilizers on the crossover, the sound is beyond spectacular but the most lifelike loudspeaker I have yet owned or heard in showrooms and as a former high end home theater installer and electronic tech, nothing comes close to the sound of the ESS HEIL 1D in my configuration. The ESS as great as it is stock, it's even greater MODIFIED.

We purchased our ESS AMT 1B speakers in the late '70's and have been using them ever since.
They have been virtually flawless and reproduce sound as well as any speakers we've heard.
All the audio "authorities" I know have all advised us to keep these units through at least four different systems; starting back in the '70's with analog and up through the new Onkyo TX-NR709 and Sharp Aquos based HD internet/digital home entertainment system we are currently running.
The only glitch was about 10 years ago after almost 30 years of service (rockin out!) we had the main speakers re-foamed; no other service or issues.
We're using the ESS front, Atlantic Technology speakers, center and rear with an Infinity BU-2 powered sub-woofer.
Our house isn't big but we can vibrate the neighbors water bed when we turn it up.
Not likely to change anytime soon!

i have listen to many speakers over the last 30 years and essamt1a or the 1b is the best by far
great low bass,the top end is all onecould ask for,i still have a pair off amt1a which i will never part with
sit back and enjoy your music

When I was a junior officer ashore in California I heard a pair of ESS AMT1 c's .... and was smitten. I couldn't afford them, and bought a pair of ARs instead, which were OK. Just.
Fast forward to 2010. I was shipping a 57 tbird back to Australia, and decided to track down a pair of AMTs to put in the container with the car, as to ship individually they would have cost a fortune. Not to mention packing.
The ship was sailing in a week... I had to work fast.
A friend in San Francisco was called upon to pick up a pair... and drive them to LA. I eventually found a pair of boxes for $100. All that was missing was the Heils, which had been sold previously. they were located in a very dodgy part of SF, and my mate said wryly. 'Tim your speakers are probably in a crack house.' Well as it turned out they were.... and nobody wanted them (the AMTs had long gone, probably sold for ... well... you know.. )
Driven to LA in the back of Gl;enns old Jaguar. 'You really owe me for this, the speakers are shot anyway'
'oh well, I reasoned, they're not costing anything to ship...'
Into the 20' container with the tbird, and a pair oh Heil AMTs I had also managed to find.
Ship sails ex LA... to Australia... via China! ... and into a force 12 gale. Great. they'll be pulp.All I cared about was the car at this stage.
8 weeks later.... after 2 transhipments, the box arrives. I am allowed to witness its opening, fearing the worst.
Tbird was fine, covered and chained down... But at the side of the container, lashed securely to the bulkhead, were 2 familiar truncated pyramid shapes, covered with blankets.
Impressive shippers, I thought. I gingerly lifted off the blankets and couldn't believe my eyes.
A pair of mint, absolutely mint boxes... with unmarked covers.
Got the woofers re-coned in Melbourne,replaced all the caps with new ones, rewired the insides of the cabinets with more appropriate cabling (the originals were like spaghetti )
and fired them up.
Wow! What fabulous sound, gutsy, gorgeous upper harmonics... just a remarkable top end.
The cabinets are now lovingly oiled and take pride of place in the lounge. These speakers look fabulous in a post modern style environment ... even the brown grill cloth is very 'now'
As to the controversy over the 'huge ' peaks in response... well my Nov 1977 Stereo review by Julian D. Hirsch raves about these speakers. " The AMT1 is a really highly accurate reproducer" "essentially perfect"
"airy open and crisp" The superlatives don't end there.
And, most tellingly, 'one of the speakers we have most enjoyed testing'
I have a $12,000 pair of electrostatics. But for every day listening with non critical listening positioning,
you just can't beat the AMT1s.
And I FINALLY got a pair, saved from a council throwout in San Francisco.
Now gracefully ageing on the other side of the Pacific.
If you listen carefully in Candlestick Park you may just hear them... playing beautifully.


couple of questions: Should I update the diaphragms, which look fine and have a fine mesh on them.
Which woofer is the best replacement? Any point in replacing the passive rad with a subwoofer, making the cabinet acoustically sealed?

The review by Marcus is 100% correct as it turns out. The frequency response of all of the AMT's were, and are very ragged indeed. This was noted by all PROFESSIONAL REVIEWERS in the years these were being produced and was even acknowledged by the designer who held the patent,, Dr. Oscar Heil . For an easy online reference that shows the HUGE peaks in response, check out the response plot shown here:

www.exdreamnet.de/.../AMT1-Klinger_Fgang.jpg

Astonishing! 10 db peaks, and then a rolled off extreme treble range. That's exactly how they sound too! modern 1" dome tweeters can be +/- 1 db through this range. Some of those are under $30 to buy.

Dr. Heil readily agreed that his units had response problems, but he felt that the more important aspect in speakers was accurate timber, and pitch. This assertion was never respected or well regarded by any other hard-science designers, and today, this seems more like snake oil then hard facts. Still. it gave a usable marketing angle for ESS to sell the product.
In fairness, the later versions such as the AMT-1B, and even better, the AMT-1C had COMPLEX and sophisticated crossover networks that massaged some of the peakiness out of the response. They do have a special sound, and some will absolutely LOVE them, while others will want to throw them off a cliff. Myself, I own a pair, and have owned others. Their unique sound makes them interesting to play with some recordings, but they are not even close to being my favorite speakers. For critical listening with excellent recordings, I prefer truly accurate speakers, not ones with a "special' kind of sound.

Hey, back in 1986I bought a pair of amt b1's at a flea market for 170.00. The sellers wife said they had to go.
When I say his expression I know they were a great find.
I just currently had them refoamed an I was amazed at the sound,if you ever get an chance to hear these speakers close your eyes and injoy. I would have paid 10 times the price if I knew they were this great.
my friend told me to name my price for them.( not for sale)
that hit very hard and you neighbors will come see what the hell is going on!!!!
Neg:
They are very heavy and not the best looking.
talk up a large foot print.

I have to disagree with the previous reviewers rating of the ESS AMT 1B.
The AMT Heil Air Motion Tweeters have no such 7 or 8 decibel peak around 7500 hz. I have a spectrum analyzer and have never measured nothing like this. In fact the Heil because of it's characteristic ability to handle a broad range of high frequencies has not mid-range driver, the Heil handles both mids and highs with aplomb. When placed in the listening room correctly the Heil demonstrates an above average ability to display a flat and accurate frequency response. However they Heil tweeter is designed to project front and back. Depending on what surface the reviewer has behind the speaker this can change the characteristic of the high end frequencies significantly. However a 7 or 8 dB increase is ridiculous and I doubt he measured such a peak. I have measured and used many speakers in the last thirty years and the Heil is one of the best imaging, best phase coherent speakers I have ever heard. In my opinion there is no better device for imaging out there. If the previous reviewer wishes to sell his AMT1 B he will find a buyer very fast.
Comparing the AMT 1B to the Dahlquist DQ-10 is like comparing a jet engine with a prop plane. The Dahlquist DQ-10 is a five way speaker using four regular speakers and one piezo-electric super tweeter. A mishmash of components that was designed in 1974 as compared to a two way speaker with significantly less cross over distortion characteristics and a 360 degree sound field with radical and forward thinking design that was well ahead of it's time.
My two cents, but I think judging by the enormous weight of positive reviews out there this speaker is fabulous. I only wish the original Company is still in business. But I hear that now the patent is with ESS Laboratories so hopefully we will see some more of these amazingly designed speakers out there!