AMT

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trianglezerius

AMT
« on: 12 Sep 2018, 05:55 pm »
Hello. I am curious what speakers under $2k use AMT or Heil tweeters. Nothing else please just the 2 I mentioned.

Thanks,
Tom


JLM

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Re: AMT
« Reply #2 on: 13 Sep 2018, 12:21 am »
You should look at Adam active monitors.  Every speaker they sell use AMT tweeters with prices starting well south of $2k.

Other companies that offer Heil or AMT tweeters in active monitors include ESI, Fluid Audio, HEDD, and PreSonus.  All use Heil or AMT tweeters and have offerings under $2k. 

JakeJ

Re: AMT
« Reply #3 on: 13 Sep 2018, 12:41 am »
Emotiva Stealth Airmotiv speakers fit the bill?

https://emotiva.com/collections/powered-monitors/products/stealth-8

Hogg

Re: AMT
« Reply #4 on: 13 Sep 2018, 12:59 am »
My favorites are from a Swiss company


http://www.precide.ch/eng/eheil/eheil.htm


Jim

dB Cooper

Re: AMT
« Reply #5 on: 13 Sep 2018, 01:30 am »
Technically a Heil driver is an AMT driver AFAIK. That's how ESS referred to their driver in the 70s, as a "Heil Air Motion Transformer" driver.

JLM

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Re: AMT
« Reply #6 on: 13 Sep 2018, 10:08 am »
Emotiva Stealth Airmotiv speakers fit the bill?

https://emotiva.com/collections/powered-monitors/products/stealth-8

The Stealth 8 is a beast, in good and bad ways.  Bombastic, brutish, great for rock - not so much for classical or small ensembles, and has the Emotiva house sound - can initially impress but lacks finesse.  Don't know about company support as Emotiva has a reputation for poor reliability and changes lineups frequently, in fact they used to offer 5 similar speakers, this last one being the biggest/baddest. 

The Adam monitors I suggested have been around for decades, are well reviewed (mostly in professional journals) and used extensively in recording/mixing studios  where sound quality and reliability are paramount.  All but the F5 and F7 models are fully German built, all are German designed.  Prices start around $500/pair and go way up from there.

SlushPuppy

Re: AMT
« Reply #7 on: 13 Sep 2018, 03:32 pm »
I forgot the Legacy monitor has an AMT and is under $2000:

https://www.legacyaudio.com/products/view/studio-hd/

richidoo

Re: AMT
« Reply #8 on: 13 Sep 2018, 09:21 pm »
I have Legacy speakers with AMT tweeter and mid. They sound really excellent. Pure accurate tone and good dynamic range, similar to other high performance tweeters I've heard. I heard the Legacy 2way bookshelf speaker a few years ago at a show, I was really impressed with that too.

Early B.

Re: AMT
« Reply #9 on: 13 Sep 2018, 09:44 pm »
AMT -- best style of tweeter I ever heard.

SlushPuppy

Re: AMT
« Reply #10 on: 13 Sep 2018, 10:09 pm »
AMT -- best style of tweeter I ever heard.

Yep. Agree 100%  :thumb:

ohenry

Re: AMT
« Reply #11 on: 13 Sep 2018, 11:07 pm »
Why not get the real deal with the original Great Heil AMT?  $1850.



Or maybe the Horn Shoppe Horn with the AMT for about the same money?



That AMT emits sound from the front and rear, and IMO is pretty special

JLM

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Re: AMT
« Reply #12 on: 14 Sep 2018, 09:33 am »
Agree that the original bipole Heil tweeter is special. 

But The Horn with that tweeter is ridiculous.  Must admit to having never heard The Horn with the Heil, but have heard the 'plain' speaker several times and don't consider it a successful design (a speaker that only a rear loaded horn fan with a bad back could love).  Sits very low (driver is about 24 inches above the floor) so can be easily 'blocked' by furniture.  Has limited output (regardless of how over driven Ed pushes them), extremely fussy to setup, and very limited bass output (needs to sit in a corner to reinforce any bass it does have).  Have heard better sound from small Fostex drivers from ported monitor sized cabinets.  So the last modification it needs is a helper tweeter, especially an expensive one.  A real mystery how The Horn ever got any market traction.

ohenry

Re: AMT
« Reply #13 on: 14 Sep 2018, 04:30 pm »
For the rational and experienced, there are many ways to get good sound.  How many folks here have survived for 19 years producing one speaker?  I know of one.  :lol:

nickd

Re: AMT
« Reply #14 on: 14 Sep 2018, 07:05 pm »
Looked up ESS last night after reading these posts. Looks like really nice product for not crazy money.
I have compression drivers up top now, but I have always thought heil drivers were the most transparent of all of the tweeter designs.

What caught my interest was the 800hz crossover on a 2 way. That’s some serious speed in the upper mids. Need to make time to get to LA and have a listen for sure.  :thumb:

ohenry

Re: AMT
« Reply #15 on: 14 Sep 2018, 08:29 pm »
Give ESS a call and talk to Ricky.  He's a really nice person.

The thing I like about the Horn Shoppe speaker is that the Fostex driver mates very well.  I cross mine over a little higher because I think the Fostex driver's strong suit is the midrange.  It does require a sub or four IMO to sound best. 

Either way, I'm a Heil boy...

SlushPuppy

Re: AMT
« Reply #16 on: 15 Sep 2018, 11:33 pm »

ed

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Re: AMT
« Reply #17 on: 16 Sep 2018, 09:02 pm »
Since this is about the AMT I reckon I might as well help you guys learn a few things. I will have to reference my favorite speaker as example but the concept  can be used in many other designs.

First, I need to say I am “buddies” with Rico (“Ricky”) CEO of ESS and I have OEM status. I do not sell The Great Heil  but can use and sell them in my designs ( I'm not restricted to just my favorite speaker) .

 You do not have to take my word for anything but if you do the research you will see I am correct in my statements, if not, by all means call me on it. Before you do you'd better have read the patents and done the research on 1st order series xover and how they are unlike any other slope or type.

The thing is, in order to take advantage of how they can benefit a DIY guy you must know they require drivers that can cover several octaves.....as like a full range speaker/driver. A pretty much full range driver and a Heil can be a perfect match.  The 1st  order series xover will insure both divers will have the exact same xover point. Change the impedance on either driver and the xover point shifts for both drivers. Same with the values, if not “perfect” the xover will just shift a little for BOTH drivers.

This is why I use The Great Heil mated to my favorite speaker. The 126 can be xovered anywhere and the GH can be safely xovered at above 1.5K or so with a 6db. Below that 12db for safety and at 800Hz you better have 18db. The sensitivity of both drivers is within a couple db of each other. This combo is ideal for the series xover and benefits greatly from it as would any design that could properly use it, IMO. I can move the xover from 1.5 to 10K if I want. The point I use is “classified”. ESS designs and almost all DIY do not take this approach and can not benefit from the series xover. I do things differently. The total moving mass of my system is 5 grams and is 97db efficient in corners as they should be.

The addition turns my favorite speaker into a true 2-way. It is not an “add on tweeter”. It is a SOTA 2-way that properly placed in corners has response to ~50Hz. Which was the design goal. A sub or 4 is always best for the bottom octaves IMO but most of my guys do not use them.....they put them in proper corners, as designed. I have a sub.

So do the research on the series xover and see if it will work for you....it will insure perfect slope for both drivers regardless of their impedance's or not exact values for the inductor or cap, even if not on perfect target so far as freq.. Xovers are seldom perfect but 1st order series  insures the point is the same for both drivers regardless.  It's special if you can use it. DO NOT USE WITH DIGITAL AMPS!

Now, this may upset some folks but here it goes.......In order to be able to discuss the Great Heil with any understanding of it  YOU MUST READ THE PATENTS!!!!!!!!!

If you don't you may say something easily disproved by them, so here goes and I'm not going to do the work for you, I'm just gonna lay out the facts.

No other “AMT” can possibly sound like them. When the patents expired all kinds sprang up. They are easily outperformed by the highest quality soft domes such as the DynAudio D-28 and it's various types.  I sure wish they still sold them DIY. Yea, being me I can snag a pair but only for personal use. No point in that!

So here is the deal.....ALL, I repeat  ALL  “AMT's “ operate with a pleated diaphragm. And that is where the similarity to the GH ends. The dispersion of them ALL is no better than any other driver and maybe not as good as the best soft domes with a proper xover.

So here is the thing few are aware of....the GH have increasing dispersion with rising frequency. They  beam less  as freq. goes up. No other driver does this I am aware of. Check out the patents....you'll understand why they look like they do and no others are it's equal.

So, there you go, don't fart around with imitators, design a speaker that can use the GH. I've given more than enough hints. This post is mainly for the DIY but everyone interested in the AMT type drivers should read the Heil patents. Knowledge is power!

Hope this helps.
Ed
ps...I kind of got dragged back to AC, I'll leave you guys alone now. Thanks for cleaning up a mess.

fredgarvin

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Re: AMT
« Reply #18 on: 17 Sep 2018, 03:03 pm »
Thanks Ed, knowledge is power.  :D

nickd

Re: AMT
« Reply #19 on: 17 Sep 2018, 11:19 pm »
More interested in the ESS Heil than ever.
Make a nice DYI project for sure. Not too sure about Ed’s comment about digital amps not being welcome to the design party? I kind of like the good ones. Plus mine does selectable phase correct crossovers up to 48db per octave.  :thumb:
I have a nice pair of Altec 12” woofers that might be a perfect match to 800hz.
I’m not to sure about cancellation at those frequencies though? The large Heil should need a wide baffle or a back wing to avoid cancellation at lower mid frequencies.
Guess I need to read some boring patent papers.  :|