ESS Heil Air Motion Transformer AMT Tweeter

Brand:| Model: Heil AMT
This is the original highly acclaimed ESS Heil Air Motion Transformer invented by Dr. Oskar Heil over 30 years ago. Unlike a normal piston loudspeaker that excites the air by alternately pushing and pulling a cone or dome, the Heil Air Motion Transformer linearly squeezes and expands its diaphram.
  • Articulate, open sound quality
  • High sensitivity
  • Dipolar output for naturally ambient sound reproduction
  • Pleated diaphragm "squeezes" air instead of pushing it
  • 800 to 20,000 Hz from a single source
  • Diaphragm shape delivers wide horizontal/narrow vertical dispersion
Part # 
Weight: 14.2 lbs.  
List Price$399.00
You Save12%
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Part # 264-600
Qty:  EA
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Product Details

ESS Heil Air Motion Transformer AMT Tweeter

The ESS Heil Air Motion Transformer (AMT) tweeter uses a folded pleated Mylar diaphragm of a mere 0.0005" thickness! Its "voice coil" is a serpentine pattern of precision-etched aluminum, selected for minimal weight and high power handling. Unlike a normal piston loudspeaker that excites the air by alternately pushing and pulling a cone or dome, the Heil AMT Air Motion Transformer linearly squeezes and expands its diaphragm's pleats, moving the airload at a very high velocity. Because the moving mass of the Air Motion Transformer is extremely low and the magnetic structure very powerful, this combination results in extremely high acceleration that yields amazing transients.

Moreover, the Heil Air Motion Transformer diaphragm's low mass and high output also allow for an unusually high combination of efficiency and bandwidth to be attained in a single loudspeaker. That is what also makes it able to efficiently reproduce frequencies over the very wide range, between 500 to 20,000 Hz. The AMT is a dipolar transducer, making it act just like a live musical instrument in many cases propagating as much sound to the front as it does to the rear, enabling a more natural and musical ambience to be heard in the listening environment. The diaphragm's shape delivers wide dispersion in the horizontal axis but tightly controlled vertical coverage. This creates a wide soundstage while simultaneously minimizing unwanted reflections from floor and ceiling. Minimum crossover frequency: 800 Hz at 12dB/octave or more

ESS still manufactures the original Air Motion Transformer invented by Dr. Oskar Heil over 30 years ago.

Product Specifications
  • Tweeter TypePlanar
  • Impedance4 ohms
  • Power Handling (RMS)40 Watts
  • Frequency Response800 to 20,000 Hz
  • Sensitivity92 dB 1W/1m
Thiele-Small Parameters
  • Resonant Frequency (Fs)1,500 Hz
  • DC Resistance (Re)2.9 ohms
Mounting Information
  • Overall Outside Diameter6"
  • Cutout Diameter3.75"
  • Depth4.25"
ESS Heil Air Motion Transformer AMT Tweeter
  • BrandESS Labs Inc.
  • ModelHeil AMT
  • Part Number264-600
  • UPC844632079771
  • Product CategoryTweeters
  • Unit of MeasureEA
  • Product Rating
    (11 Reviews)
  • Weight14.2 lbs.
  • California Prop 65

    Warning: California residents only. Please note per Proposition 65 that this product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

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ESS Heil Air Motion Transformer AMT Tweeter
ESS Heil Air Motion Transformer AMT Tweeter is rated 4.6364 out of 5 by 11.
Rated 5 out of 5 by from Sound as Clear as Light! Truly!I can't heap enough praise onto the sound of these speakers. The first time I'd ever heard these incredible drivers was way back in 1973 at an audio salon in Champagne, Illinois. The salesman let me hear them in comparison to the Large Advents (which I ultimately purchased). I wanted the Heils so bad, but they were way, way out of my budget. Like $1500.00 out of my budget, and that was 1973 dollars. So all my days I've had this impression of the Heils and have always wanted a set. Now, available through Parts Express, I have made my purchase of an audio icon, and having connected them just this morning, the sound is as crisp and clear as I remember. They arrived well packed, each driver in its own box. They are quite heavy, mostly due to the magnet structure. Approximately 15 pounds each, they come wrapped in a nice string pull pouch (surrounded by stiff styrofoam) with a serial number verification card. 2 wires are dangling freely from the bottom, the connections, one purple (+) and one blue (-). I have them connected using an Ashly XR1001 crossover, 1 kilo-hz crossing frequency using a Linkweitz-Riley response curve. The sound is just as I remember way back in 1973, clear and crisp with such detail, only a listen can give the true experience. I urge anyone who has ever wanted to hear reproduced music the way it should be heard, GET A SET OF THESE!!!!
Date published: 2014-10-12
Rated 5 out of 5 by from The Great Heil AMT.I have just completed some measurements of #2230 and 2231 and have found them to be virtually identical in impedance and frequency response. The impedance is 3.6 Ohm between 1.2 to 8 kHz and droops slightly to 3.4 Ohm at 20 kHz. The main resonance occurs at 550 Hz.The SPL measured 92 dB at 1 M on axis with a 2 V input at 1 kHz.The SPL increases linearly with frequency to reach 102 dB at 20 kHz.Parts Express delivered these items on time and extremely well packed.
Date published: 2014-04-10
Rated 5 out of 5 by from Very low distortion!These are very good, distortion is low and 3rd harmonic is lower than 2nd. I have posted some data on my web site. I will be using these along with the Tang Band W8 1808 8" full range in an open baffle system using miniDSP for the crossover-EQ. Based on the measurement data I see no reason not to cross them over around 1200 Hz. I would not cross them much below this however, definitely not the suggested 800 Hz. If you are crossing them passively or otherwise not using any EQ, you may want to cross them higher but with DSP EQ you will easily be able to flatten out the response. I expect this to be a very good match with the TB W8 1808.Monte
Date published: 2014-03-18
Rated 5 out of 5 by from This tweeter in ESS AMT 3 Rock MonitorThis tweeter in recently refurbished ESS AMT 3 Rock Monitors
Date published: 2014-03-16
Rated 5 out of 5 by from Dream to cross overI am on my third build with these and would just like to counter another review that was negative about designing and building crossovers.These are the easiest speakers to crossover - period.Just make sure you have a fast woofer.Typically at 2Khz 3rd order crossover. Fewest parts = no color.Simply beautiful sound.
Date published: 2013-08-14
Rated 5 out of 5 by from The best compromise with dynamic speakersI must say that I have been impressed with the Oscar Heil since the 1970 with the AMT 1 It featured a 12 inch bextrene woofer with a flat passive radiator. I hear these driven with a Phase Linear Amp and they were crossed over at 800hz with a second order passive crossover. I actually thought they sounded good until I heard an electrostatic panel speaker.Skip to the present. I realize now that the crossover was much to low and the woofer much to slow to match up. I am using this driver with the Tang Band 1772 wide band driver. This is the only driver efficient enough and fast enough to be used with the Heil. I actually use the new mid sized Heil with an 8 ohm load instead of the 4 ohm. I also use a 4.7 mf capacitor to the Heil for a first order crossover. The Tang band driver has a peak around 1000 hertz that can easily be compensated for with a .15 mh inductor with a mills 4 ohm low inductance 12 watt resistor . The reason I prefer the Heil over ribbon tweeters is that the Heil is able to reproduce the lower treble much better than a ribbon. This has to do with surface area. The Heil has close to the cone area as an eight inch woofer. The second reason is though the Heil is very fast a ribbon is just a bit quicker and thus almost impossible to find a fast enough mid range. Nola does a wonderful job with 4 raven ribbons retail $800 each and four dedicated mid range drivers. The crossover I believe is 3rd order. My recommendation to you is just buy the Tang Band and use a 1st order crossover and you will be very happy. Nothing even close to the money will match these two. Happy building hifiralph
Date published: 2013-04-03

Product Q&A

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ESS Heil Air Motion Transformer AMT Tweeter

Is there any chance these may be back in stock before October 3rd, and can I purchase them while they are out of stock?

Asked by: Hammy Technoid
Please contact our sales and customer service for available stock, price and shipping options. sales@parts-express.com or 800-338-0531 x2.
Answered by: MattP
Date published: 2014-09-24

Does it come with mounting brackets?

Asked by: Bigsound
These do not include or require brackets for mounting.
Answered by: MattP
Date published: 2014-03-18

Can I cross this with 800-5khz band pass crossover as a mid-range?

deos it work with 800-5khz band pass 4ohm crossover as a mid-range?
Asked by: Bigsound
I see no reason this won't work as long as the crossover is at least 12 dB per octave.
Answered by: MattP
Date published: 2014-02-12

ESS classic pedestal speakers

Was wondering if i can buy just the heil transformer for these speakers... bought in late 70s and would love to recreate the sound. would like to get two heils and four woffers for said speakers... can you help me...chris...
Asked by: cjsmiles
the Heil sound was a sound that exhibited very open and articulate midrange and high frequencies when it came to Lows and the woofer they weren't special, but also did an acceptable job at reproducing the frequencies although not exceptional. The impressive sound these speakers exhibited was primarily in the high and upper mid range frequencies. I would recommend any good enclosure vented with 2-8s, 2 10's or even 212s and the heil motion Twitter provide appropriate crossover network and you would be home free what's a good quality 19 seventies hi fidelity sound.
Answered by: Nitnub
Date published: 2014-02-12

Can I use the ESS Heil AMT to replace the horn tweeter in my Klipsch Heresys?

If yes, would I need to reconfigure the crossovers (Bob Crites replacements of the originals) or would the ESS Heils AMTs be a simple "drop in"?Any and all opinions, thoughts are welcome.MTIAHarry FreibergBrookings, OR
Asked by: hapiniregon
Hello,Not an easy answer.Yes you can, and you will gain a lot in terms of refinement. But this is not gonna be plug and play!you will have far less efficiency with the ESS, which means you will need to rajust the level, and/or move to biamplification.The ESS is 95dB/w at 4 ohms.The horn driver of the Heresy may reach 100dB/wOn the other hand, the ESS will be easier to filter and to drive.But you will have to redesign the filter.Good luck
Answered by: Philippe Croft
Date published: 2014-02-12

can the ESS Heil Air Motion Transformer AMT Tweeter be used in a three way system/crossover? Using a crossover from a pair od pioneer DSS-10E's.

Asked by: grumpy96
If you have never listened to a pair of the Heil transformers you are open for a shock. They are the ultimate for acoustic instrument reproduction and great at amplfied instruments. This is because the vibrate much like the sound box of an acoustic instrument.Your Pioneer 10E speakers are cloth/ paper cones and have a good responce time characteristic. I think the mid crossover frequency is 800 Hz. If this is accurate, I would consider using it as a mid tweeter. If not then replace the tweeter, except I would mount it on top of the box. I have not heard your pioneers since the mid 1980's, but they should compliment each other. Remember, Heil created these over 30 years ago and they continue to remain one the best in reproduction.I know a band with a very good fiddle player. They added 4 (2 per side) to their FOH pa and the fiddle is unbelievable. Prior through the horn it was screatchy notes, now it is great.My advice is yes, and you will love the end result.
Answered by: Nitnub
Date published: 2014-02-12

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