ESS AMT1 "Great Heil" tweeters

[Jed]

I contacted ESS, and it appears these tweeters can be purchased again. I had the experience of hearing these tweeters recently, and although the specs aren't "perfect" the sound is magical. I'm considering buying a pair to try with a W22EX midrange and RS225s woofer. I think this system would be awesome. The AMT tweeter just produces so much life and air around subtle detail it is almost ghost-like. Some claim the newer Raven ribbon technology is better or new domes measure better- but man do these tweeters sound amazing. I'm interested in knowing more about your experiences with the AMT1. I've used ER4, but they just don't compare IMO.

Jed

PS- JohnL check your pm :T

[ThomasW]

Yep they have a very distinctive sound. You might want to actually measure a pair before deciding on the remaining components

[TacoD]

They are large , never heard one though. Can you describe differences between ER4 and the big Heil?

[Jed]

They are large , never heard one though. Can you describe differences between ER4 and the big Heil?

I didn't get a chance to A/B compare the ER4 to the big Heil, but based on my experiences I would have to say the ESS reproduced sounds around the tone- more resolution of microdynamics, where the ER4 would just produce part of the sound. Where the ER4 is neutral and unoffensive, the ESS could be called natural, which is neutral but with the added nuances of real acoustic performances. There was presence and an uncanny amount a realism. I haven't been this blown away by a tweeter in a looooong time. The measurements that I have seen suggest a high directionality at the top end, which may be true but it didn't take away from the music. The ESS is "fast" and deserves a fast midrange with low distortion. This suggests a W22EX midrange, since the ESS can be crossed pretty low with steep slopes. I need to listen more to determine how effective the ESS is below 2K, but my first impression is very good indeed.

Jed

[Jed]

Here is some data I found on the internet. Thoughts? Does anyone have distortion data on these?

I spent some time comparing my friends system that uses AMT1 and my system that uses OW1. I'm wondering if it is the low crossover point that is the main advantage- that is, using a good tweeter to cover the range from 1.3K on up, versus my sytem where the OW1 is used above 2.2K.

Jed

[TacoD]

In my experience tweeters with a large surface sound less strained. Also crossing < 1500Hz give more spacious sound (better radiation?).

[JohnL]

Hey Jed,

I would agree that they definately have a 'sound' that is very agreeable. I'm not entirely sure what produces that, but they sound nice to my ears. I have a couple of designs here that use Fountek metal ribbons (old JP2 and JP3) and they don't sound the same. Nice, but not as good as the AMT. I also have a set of ER4s here, but I can't say I ever listened to them. They belong to a project that's a bit further down on the list. I sent you a couple of emails, which I guess you haven't received. There is some measurements, some thoughts, some warnings and a crossover diagram for the RS225/AMT combo. Check your mailbox or perhaps they got caught in a spam filter somewhere, they had 2 attachments; a jpg and a zip file.

John

[mikec]

Here is some data I found on the internet.

I was disappointed to find the two sets of AMT1 drivers I purchased directly from ESS measured quite differently than some of the published curves that I had seen on the web. My correspondence with two others who also purchased the drivers confirmed that my measurements were indicative of what ESS is currently selling. YMMV.

[Jed]

Mike,

That is really bad news. What do you think is causing that dip? I noticed the new tweeters have a slightly different element that has a protective covering-fabric. I wonder if that is the problem. I asked ESS if the current AMT1 is the same as the vintage tweeter and they replied that it's the same and is used in their current speakers as well...

Jed

[mikec]

Jed, It appears to be a cavity resonance. My measurements were taken nearfield and there is a good chance that the response will flatten out at a distance. I plan to take more measurements when I have more free time. Cheers, Mike

[JohnL]

Jed, It appears to be a cavity resonance. My measurements were taken nearfield and there is a good chance that the response will flatten out at a distance. I plan to take more measurements when I have more free time. Cheers, Mike

FOAM is your friend! Some little wedges of acoustic foam in the V does wonders to flatten the response out.

I bought some new AMTs from ESS as well. I haven't measured them yet, but they sound pretty close. How they look, is another question. It looks to me like they pulled a mold off an older AMT and the mold wasn't that great. Thinner plastic, rough casting, thown together. Don't get me started on ESS, I will never do business with them again. It's a shame, because I love the AMT so much. If I ever need any more I'm buying them from Ebay.

John

[Jed]

FOAM is your friend! Some little wedges of acoustic foam in the V does wonders to flatten the response out.

I bought some new AMTs from ESS as well. I haven't measured them yet, but they sound pretty close. How they look, is another question. It looks to me like they pulled a mold off an older AMT and the mold wasn't that great. Thinner plastic, rough casting, thown together. Don't get me started on ESS, I will never do business with them again. It's a shame, because I love the AMT so much. If I ever need any more I'm buying them from Ebay.

John

John,

Could you send me a picture of the new tweeter? Does it look like the tweeter they have on their webpage? It's hard to see it in detail.

Mike,

Do you have the same quality issues?-- Just wondering if I should take a chance with ESS or not. Who knows when a pair of mint condition ESS AMT will come on ebay again.

[noah katz]

I don't see the AMT listed separately on the site.

Interesting that in their own systems they cross them so low - 800 Hz.

How much are they?

Thanks

[Curly Woods]

ESS AMT on EBay

John,

Could you send me a picture of the new tweeter? Does it look like the tweeter they have on their webpage? It's hard to see it in detail.

Mike,

Do you have the same quality issues?-- Just wondering if I should take a chance with ESS or not. Who knows when a pair of mint condition ESS AMT will come on ebay again.

I did a search on EBay last night and found a pair up for auction. ESS AMT did the trick. Cheap so far.

[Jed]

I don't see the AMT listed separately on the site.

Interesting that in their own systems they cross them so low - 800 Hz.

How much are they?

Thanks

$150 each. I think they cross them over too low- from what I understand there is a lot of distortion below 1000hz.

[noah katz]

Thanks.

Hmm, maybe a waveguide to lower the distortion.

[Jed]

Thanks.

Hmm, maybe a waveguide to lower the distortion.

They sorta have a waveguide because of the way the magnets are structured, but what was your idea for the shape of a different waveguide? Distortion is pretty low all the way to 1000HZ, from what I've heard from various people who saw the tests in Klang and Ton/Hobby Hifi. I took a chance and ordered a pair today actually- money order sent. I've had a few people email and tell me I have nothing to worry about... so lets hope they are right.

[noah katz]

I just started reading about waveguides so I don't know how to design one, but they have many nice advantages:

1) Greater directivity to lessen sidewall reflections in my long, narrow room

2) Greater efficiency, which may really be the focusing effect of 1), as opposed to the actual increase in electrical to sound energy conversion that a horn gives

3) Lower power compression and distortion

[mikec]

Since mine have been sitting idle collecting dust I'd consider selling them to anyone interested. This pair was purchased new from ESS not long ago and have seen no use. PM me with offers if interested. Cheers, Mike



Click on image for full-size photo.

[Jed]

Since mine have been sitting idle collecting dust I'd consider selling them to anyone interested. This pair was purchased new from ESS not long ago and have seen no use. PM me with offers if interested. Cheers, Mike



Click on image for full-size photo.

Say it aint so... I just sent payment to ESS today- oh well someone else will have to get a deal. Just don't let them go too cheap otherwise I'll feel REALLY bad....

[CraigJ]

Say it aint so... I just sent payment to ESS today- oh well someone else will have to get a deal. Just don't let them go too cheap otherwise I'll feel REALLY bad....

Jed, did you ever receive these?

Craig

oops, found this from your later;

"I'll start. I've tried 3-ways with W22, W15CH, OW1, then RS225, W15LY, OW1, then RS225, W15LY, and C12, and currently I am using the RS225 with ESS AMT tweeter. I'm thinking about exploring a speaker with either (A) dual RS225, Peerless 883, and Accuton C24 in a Wilson Sophia type enclosure, or an (B) opus clone with a single RS225, C79, and C12. I'd imagine option A would have more SPL potential, but option B might be more refined. I also like the idea of using newer driver designs, so option A would be interesting in that regard as well. So let me know what you think about these 2 options and what you are working on as well.

Because of my recent success with the ESS Heil tweeter, it has me thinking more about dipole B&G RD series drivers."

Jed, never mind, I guess the question is, did you like the Heil Tweeter, and how would you compare it to your current projects?

Thanks,

Craig

[Jed]

Hi Craig,

I've heard a few versions of the ESS AMT1. The older version sounded better to me than the new one, but I see now (it's 2009) ESS is back in business with a new production run. I have no idea how they will compare until I test them or if I decide to pick up a pair from PE. I've designed a lot of speakers since that last post in 2006, so it's a bit hard for me to compare these tweeters to my new designs having not listened to an AMT1 for along time.

Jed

[ThomasW]

Years back Nelson Pass posted about the sonics of the various materials used to make the diaphragms. Here's what he said....

As I recall the original Heil diaphragms were polyethylene, not Mylar or Teflon. These later materials were tougher, but never sounded as good.

Since I have no choice I'll take the newer more rugged Mylar diaphragms...

[CraigJ]

I don't know how much of this became reality, but according to Ricky's (of ESS) post from 08-07. #76 from DIYAudio:

"My name is Ricky caudillo
ESS is back in the U.S.A we are making the diaphragms to the original patent WE HAVE 1107S IN STOCK We will have more models available soon.
Please give me a call 310-962-0114 will give you more details.
We moved every thing from Sacramento to southern California we are in the process of relocating the Germany operation back to los Angeles

Leo David the original owner wants to keep it here

So pass the word out we are back

Thank you

Ricky caudillo

post at Diyaudio, on 09-07 Post #89
"hello
as for the material we will go back to the original mylar as per
oskar hiel patint the circut is a double sided we have made all new tooling to the original specs.
thank you
ricky
ess"


Craig

[el_seven]

Years back Nelson Pass posted about the sonics of the various materials used to make the diaphragms. Here's what he said....Since I have no choice I'll take the newer more rugged Mylar diaphragms...

They're not as bright as the older diaphragms and the old units are available a-plenty. I bought the new ESS ribbons recently and pulled the old diaphragms out to find this the case. The old ones went back in! If you want a new pair of mylar diaphragms, you can buy mine from me.

[ThomasW]

To each their own......

Others have posted they prefer the sonic quality of the new diaphragms over the old ones.