Clarity, Detail, Imaging, Power Handling, Sound Field Depth,

Narrow vertical dispersion Heil, room placement is crucial, Heavy To Move

The Heil AMT (Air Motion Driver) is perhaps one of the best high frequency drivers ever conceived. Driven with clean power and good source material, AMTs can deliver such nuances in detail and imaging that is truely amazing. The AMT design is actually found in other manufacturers of fine loudspeakers, especially in Europe - just do a search for "AMT Heil" on Google. The AMT 1Bs and their successors (see below) use the bipolar design allowing for a more open sound stage, though bipolar designs require a bit more care with how you place them in a room due to rear surface reflections. The AMT 1Bs and AMT Monitor's were built like a rock, weighing in approx. 90 and 110 pounds respectivly.

Apparently, ESS Loudspeakers still manufactures and markets the AMT series - now version 1D, along with a full line of loudspeakers. Check out their current models and the prices at this website:

http://www.speakeress.com/IBS/SimpleCat/Shelf/ASP/Hierarchy/00.html

I think the newer AMT 1Ds are priced less than what the 1Bs were selling for 20 years ago. They appear, from the photographs, to have the same classic styling and construction quality as their predecessors, though it looks like they're using new woofers materials (polypropylene instead of paper).

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AMT Monitors

Heil. Midrange bass. Solid on the upper-bottom range. High range is incomparably good.

Replaced the foam after 14 years

The AMT1b's have been a solid performer since we bought them in 1978. Polycones still look and perform as new. Had to replace the foam after 14 years but that was easily accomplished. Drove 80 miles to the ESS shop in Sacramento and everything was there. Even bought new grill covers that had been scratched to heck by a cat. NO MORE CATS! :-)

Running these through a 5 year old Denon AVR 202 receiver (an Onkyo prior to that) really shows the strength and thought that went into these speakers. Component video sound, Dolby Digital, etc., are superb - simply excellent. I run Niles 800rp's inwall speakers for the rears and an Infinity 1000 for the sub. The sound is as good as anything I've ever heard. The only uprade will be for either a new DTS receiver - or preamp for the Denon. Decisions, decisions.

If you get a chance to pick a set of these speakers up you should grab them. Sure their big, bulky - but their shape fits into any decor. More importantly, so does their sound.

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Noen really - waited to buy the best the first time.

everithing

none

This for AMT1A

I buy thes in 1985 , never find so an amazing qualty of sound
I need to replace after 15 years the menbranes and for
an average cost of 150$ , I am going back to heaven

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infinity,vandersteen

I worked for ESS (Sacramento Calif)in the mid to late seventies. Strangely enough I never did buy any speakers for my own use. At that time was in love with the midrange of the 'Bozak Symphony' - they were my speaker of choice. However I did purchase seperately the 'Heil' driver - at the time sold under the name 'Elite'. When added to the Bozak, which needed a boost in the top-end the sound was quite amazing. I still have those 'Bozaks' although now they are stuffed neatly away in my closet. I am plan on refurbishing them later this year. I am currently running NHT 2.5i. I am looking forward to the comparision between the two. Norm......

Treble ambience, transparency

woofer mis-match and too low crossover

These are legends but the sound is dated in the midrange and bass so I have rebuilt them into a 3 way using another legend driver, Yamaha NS1000 berrylium midrange and 2 7" Scanspeak carbon woofers. Sound much better than the old AMT 1C bookshelf units. Check out the pictures on this photo website: http://communities.ninemsn.com.au/berryliumthing/berryliumheilss.msnw

The highs are really fantastic. Forget about the ribbon and the ceramics.... Only the electrostatic or Magenplanar can match

Very strong magnetic field: can destroy your TV screen or your analog watch

I bought a used pair of Heil tweeters, bass units + passive radiators and crossover ( ie. AMT 1b without the wood cabinet ). I have only used the Heil unit to match my desktop Mission 751. What more can I say? Simply perfect treble, 100 marks. Period.

I just don't know how the 12 inch woofer can match such a transparent tweeters. No wonder every body complains about the discontinuity. Now my mission bass is Ok but it is still a waste to use the Heil unit in this way. Probably I may try to match it with a bass unit with excellent transients.

The crossover is rubbish. A treak: discard the resistors and capacitors controling the "midrange" and replace them by a 4 ohm resistor and you can hear the difference. Also change the treble capacitors to film cap ( I am using Kimber )

Unbeliveable sound and quality. Value for the money. Tuff. Unless you are running a piece of &^%#$@ amp, you can't hurt them.

No current sales available in the U.S.
Size -alot of folks are looking to satelites and subs now.

I wrote the original review on these speakers and I'm back to follow up. Simply put, these baby's are the most unreal listening experience you'll ever have. I have heard many other brands, and NONE can compare. I used to sell audio and I have heard plenty of the competitors and they can't compete. Remember too that this design is at least 20 years old. They sounded awesome before C.D.'s were around. Now with C.D.'s, it is like a musical orgasm. I honestly can't believe some of the nick picking that I have read on this site regarding these speakers. Get real! For the price, you can't get ANYTHING better. They even sound better than speakers twice thier price. The only, and I mean only thing that is a negative is thier size, and I've seen some potential 5 star ratings knocked down a few notches due to that. Personaly, I would never give up such an astonishing piece of musical equipment because of size. If you want a listening experience that can't be rivaled, make the space. However, if you absolutely can't fit them, look to some of the other smaller ESS's maybe. Get a pair of these baby's if you can. On a rating scale of 1-5 I give them a 20!!!

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None - Why stray from perfection

Sound is superb.

Grill covering and frame can work loose.

I've owned a pair of these AMT1B's since 1977. They have withstood the test of time and four moves. Everyone is impressed with their sound. The Heil component looks weird but, what the heck, it produces a pristine sound that fills the room. I bought these during the days when you really had to shop, listen and compare before buying (and when I had the time to do so). I've noted that the Heil tweeter-midrange component has a better side-to-side dispersion than up and down. I have slightly elevated the front of the speaker using a shim to counter that perception. If you own a pair of these speakers, ESS will send you replacement woofers and passive bass radiators for a few hundred dollars. Back in 1993 the overhaul cost me about $275 with shipping (they wanted the old woofers back, too). Replacement was extremely easy. Reason for replacement: the foam lining of the woofer cone and passive radiator deteriorated to the point that holes were letting air escape. I was informed by ESS when I called them that the foam deteriorates over time, primarily from bacteria which eats it. Regardless of the etiology of the deterioration, I was promptly sent the replacement woofers and radiators and they fit and worked great. I'll be sad when my four-year old goes at those speakers with some sharp object (which is inevitable, right?). I do so hate being a fatalist.

I have owned my AMT1s for more than 25 years-one is on its 2nd woofer, one's on its 3rd. I agree with the two somewhat critical reviews posted, much as I love these speakers. I think the answer is they simply can't play loud. That is to say, they can take just about anything without damaging them, but they won't sound very good. The diaphragm's geometry changes when it moves. The longer the motion, the more this will affect the performance. Because the ends of the diaphragm tend to hold the folds in place, the center portion actually moves quite a bit more than the rest. (I just confirmed this with a battery) This is where the touching must occur when overdriven. Nobody seems yet to have mentioned the most important tweak for these speakers (pyramid cabinets only): Loosen the retaining bolts and insert a pencil under the front of the Heil unit. This will place the diaphragm in roughly the same plane as the woofer. It makes a big difference, if only to tilt the dispersion pattern up toward people's ears.
These speakers really only work properly with some sort of graphic equalizer. With an EQ you can roll off that sizzling high end, and try to balance the woofers. BTW, Why do these speakers sound SO bright, despite measuring flat? Speakers are measured from a position directly in front of them. All conventional tweeters are "beaming" all their energy in that direction. The Heil unit is radiating its energy out in a nearly 360 degree pattern horizontally. This won't be measured in an anechoic chamber, but you'll sure hear it when there are walls to bounce that energy back in your direction.
One last thing- I do not recommend the new ESS speakers. It is not really the same company, but some other manufacturer that bought the name and remaining stock when the original went belly up. Some reviewers have been OK with woofers, but the new AMTs are decidedly inferior. The aforementioned mesh was an absurd idea. Also the diaphragms they are producing are using a much thicker mylar. This, in combination with going to what appears to be gold foil, have made them much more massive. This pretty much defeats the purpose of the design. BTW, this isn't theory- I wasted quite a bit of money buying some of these units to play with. They sound awful- all of the Heil's bad characteristics amplified.

I have owned a pair of AMT 1bs since 1979 . I replaced the passive radiators and reconed the speakers last year (parts from ESS). Yes, the heil unit is impressive, but, on program material with dense high frequency information or when listening to less than top quality recordings or CDs they can sound downright harsh. Using better than average electronics, cables, etc. helps a lot, but I find that after 20 years I am still tweaking in order to tame excessive brilliance/harshness. I also agree with other reviewers that the bass speakers are not well balanced with the Heil Units. Despite this, I should point out that with every upgrade I make in the rest of my system, these speakers always sound better. The rest of my system consists of a high end Denon CD Player (Model?), Rega Planar 3, Electron Kinetics Eagle 2a Amp, Superphon Revelation Preamp, NAK Cassette, and antiquated speaker cable (Thinking of replacing speaker cable to Kimber 4TC which I hear has good bass and sweet highs). A local, in the know, audio guy has suggested the possibility of modifying these speakers for biwiring - and predicts a big improvement - hmmm. Anyway, I think these were great speakers, but if I could afford to lay out $1200 (CAN) or so I would definitely opt for something else.