Thaddeus Smith Posted February 8 Share Posted February 8 Approximately four years old, pulled fully working from a franken-scala project I threw together and am now dismantling to pursue other things. Qty 4 drivers total, will sell in pairs and will be shipped with original OEM boxes/packaging. Currently selling from ESS for $250/each, I'm selling these for $375/pair, shipped and paypal'd in the conUS. Invented by the noted physicist and scientist, Dr. Oskar Heil, the ESS Heil Air Motion Transformer (AMT) tweeter uses a folded pleated Mylar diaphragm just 0.0005" thick. Its voice coil is a serpentine pattern of precision-etched aluminum, selected for minimal weight and high power handling. https://essspeakers.store/collections/heil-amt/products/original-great-ess-heil-air-motion-transformer™-i-large 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. Weight: 14.5 pounds Height: 6″ Width: 6.75″ Depth: 4.25″ Impedance: 4 ohms, Re: 3.9 ohms Power: 40 Watts RMS, 160 Watts Max Response: 20 kHz - 800 Hz Sensitivity: 96 dB, 1 watt, 1 meter Fits ESS Cabinet and Driver Models: ESS: AMT-1. AMT1, AMT-1A, AMT-1B, and many more 4 Quote Link to comment Share on other sites More sharing options...
JohnJ Posted February 10 Share Posted February 10 I remember hearing some of these years ago on top of some speakers. Their presence and the dispersion of treble was very nice. Think Infinity started using some similar foil tweeters soon after that. But not with the ingenious Thermalright Heatsink looking housing! GLWYS 3 Quote Link to comment Share on other sites More sharing options...
Vahorns Posted February 10 Share Posted February 10 Try Money by Pink Floyd with the ESS AMYs --- unreal - stunning - spectacular ... 2 Quote Link to comment Share on other sites More sharing options...
MookieStl Posted February 11 Share Posted February 11 This would be a cool project! Thad a good dude (a bit snarky) to deal with. Good luck on a great deal. 2 Quote Link to comment Share on other sites More sharing options...
jwc Posted February 12 Share Posted February 12 Does anybody have a frequency response of this speaker. Does it require EQ? Is it really usable down to 800 hz? Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted February 12 Share Posted February 12 8 minutes ago, jwc said: Does anybody have a frequency response of this speaker. Does it require EQ? Is it really usable down to 800 hz? ChrisA posted some information here JC 2 Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 12 Author Share Posted February 12 2 hours ago, jwc said: Does anybody have a frequency response of this speaker. Does it require EQ? Is it really usable down to 800 hz? The thread above is what spawned my interest in doing this, and Chris very much held my hand all the way through the tuning process. So I don't presume to understand it all, however, this was a raw full-range sweep of one channel @1m, with the drivers stacked and wired as recommended, in the custom "wings" discussed through the thread. We went through a few rounds of EQ tuning per L/R channel, once with HF/Mid/Subs individually, and then three more rounds with them as a single speaker. 1 1 Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 12 Author Share Posted February 12 After tuning, my full left channel looked like this (TH-SPUD + LS Bass bin + AMTs): 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted February 12 Share Posted February 12 It took TWO per side for sufficient low frequency response IIRC. If the LF cabinet being used goes higher one might be able to get just 1 per side to suffice. I mean Heil does so why not. Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 12 Author Share Posted February 12 7 minutes ago, babadono said: It took TWO per side for sufficient low frequency response IIRC. If the LF cabinet being used goes higher one might be able to get just 1 per side to suffice. I mean Heil does so why not. Correct, along with a bit of additional wave guide/"horn" ..which is why I have two pair available for sale. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted February 24 Share Posted February 24 On 2/12/2024 at 4:09 PM, Thaddeus Smith said: Correct, along with a bit of additional wave guide/"horn" ..which is why I have two pair available for sale. You are lucky the price went back up. They were available for like, $150 new for a while, which would kill your attempt at selling. I have 4 of them myself, so not need. GLWS. Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted March 9 Author Share Posted March 9 Buuump. Make an offer. I like amps, too. Quote Link to comment Share on other sites More sharing options...
dkalsi Posted March 12 Share Posted March 12 On 2/12/2024 at 1:00 PM, jwc said: Does anybody have a frequency response of this speaker. Does it require EQ? Is it really usable down to 800 hz? Here is the measured raw response (with 80uf protection cap): 1 Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted March 12 Author Share Posted March 12 2 hours ago, dkalsi said: Here is the measured raw response (with 80uf protection cap): Is that one driver on its own, or two in series with a horn? Quote Link to comment Share on other sites More sharing options...
dkalsi Posted March 13 Share Posted March 13 15 hours ago, Thaddeus Smith said: Is that one driver on its own, or two in series with a horn? That was one on its own - without horn. Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted March 13 Author Share Posted March 13 Thanks! just wanted to make sure measurements were correlated with the appropriate variables. Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted March 30 Author Share Posted March 30 Buuuuuuuuuuuuuuuump Quote Link to comment Share on other sites More sharing options...
wildchild Posted April 13 Share Posted April 13 (edited) Would these work just using them as tweeters on top of a fh-1 bin and PRV wg 45-50 mid horn? Edited April 13 by wildchild Quote Link to comment Share on other sites More sharing options...
wildchild Posted April 13 Share Posted April 13 On 3/30/2024 at 2:21 PM, Thaddeus Smith said: Buuuuuuuuuuuuuuuump Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted April 13 Author Share Posted April 13 Probably, yep! I know someone using them as a super tweeter with jubilee and he's pleased with the sound. And I used them on LA Scala bass bins. Quote Link to comment Share on other sites More sharing options...
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