Anyone used these?
Reading rave revues about this type of tweeter, especially the Mark & Daniel models and the ones used by Burmester. Some of them can be crossed over 2nd order and also well into the midrange too.
Could someone explain this entry on wiki about the dipole effect and not being suited to certain cabinets? I don't understand it.
Air Motion Transformer - Wikipedia, the free encyclopedia
"While apparently very good as a mid-tweeter or full tweeter, the AMT is not commonly employed as much as one may expect in lower-end speakers. This is due mainly to the AMT's characteristics of a dipole sound radiator, which makes enclosure in traditional speaker cabinets difficult without sacrificing sound quality or employing sound reflex baffles. The AMT can reproduce sound down into the low midrange fully competently, making design decisions regarding crossover points difficult."
Reading rave revues about this type of tweeter, especially the Mark & Daniel models and the ones used by Burmester. Some of them can be crossed over 2nd order and also well into the midrange too.
Could someone explain this entry on wiki about the dipole effect and not being suited to certain cabinets? I don't understand it.
Air Motion Transformer - Wikipedia, the free encyclopedia
"While apparently very good as a mid-tweeter or full tweeter, the AMT is not commonly employed as much as one may expect in lower-end speakers. This is due mainly to the AMT's characteristics of a dipole sound radiator, which makes enclosure in traditional speaker cabinets difficult without sacrificing sound quality or employing sound reflex baffles. The AMT can reproduce sound down into the low midrange fully competently, making design decisions regarding crossover points difficult."
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I am currently modifying a standard 4-way Danish louadspeaker from Audiovector with an ELAC heil tweeter. I think it is an outstanding fast tweeter, but when I measure it, it rolls off around 2800 hz, so nowhere near lower mid-band. But this is a little tweeter compared to the size of the AMT, which is proposed to be used down to 1500 hz... I am fully satisfied with the sound but this one demands a very high quality mid-band driver. So I have changed the standard Peerless HDS with a SEAS Excel. -And I will do the same for the woofer...
These are the ones I'm looking at - pretty good price imo
Heil Air Motion Transformer Drivers to be Available for DIY - AudioJunkies
Heil Air Motion Transformer Drivers to be Available for DIY - AudioJunkies
That's strange, I have a pair of DM-4 laying on the shelf... 
Maybe you should look at the Eton ER4 instead, the M&D driver is one of those drivers people rave about when listening to them in systems but they don't measure so good by themselves. I haven't hooked my pair up yet but they sure sound good in the M&D systems I've heard.
Maybe you should look at the Eton ER4 instead, the M&D driver is one of those drivers people rave about when listening to them in systems but they don't measure so good by themselves. I haven't hooked my pair up yet but they sure sound good in the M&D systems I've heard.
Yeah - be careful about visiting their website - my anti-virus software blocked them from loading photo's. Every time I went to a new page Norton blocked the photo and warned me that I had just been attacked!!!!
Lots of info about AMTs in this thread, especially the Beyma TPL150:
http://www.diyaudio.com/forums/multi-way/142015-my-open-baffle-dipole-beyma-tpl-150-a.html
http://www.diyaudio.com/forums/multi-way/142015-my-open-baffle-dipole-beyma-tpl-150-a.html
I kind of wonder about Zaph having "expressed some interest..." Here's a brief snippet:
"Lets start with the good: non-linear distortion is decent and these tweeters do indeed work very low. A steep 900 or 1000 Hz crossover would be fine.
Now for the bad news: everthing else about these tweeters was horrible."
Zaph|Audio
"Lets start with the good: non-linear distortion is decent and these tweeters do indeed work very low. A steep 900 or 1000 Hz crossover would be fine.
Now for the bad news: everthing else about these tweeters was horrible."
Zaph|Audio
Yeah, those particular Mark and Daniel were pretty bad, huh? The Beyma TPL are a different story though. See my build here:
HTGuide Forum - Lambda TD12's + AMT monitors
I would say that I prefer the larger Raal though. Can't cross as low, but much better resolution and just sounds so right and effortless.
HTGuide Forum - Raal, Neo 10 open baffle
Greg
Back in the 70s I had 4 ESS AMT-3S in quadraphonic configuration. The AMT-3 had a huge Heil AMT driver 8"W by 6"H by 4"D magnet with a 6" by 2" diaphragm, and 2 10s per speaker. Powered by a Phase Linear 700 and a Marantz 500, those babies would rock. Except for the Quads and Maggies I thought the highs were some of the best available at the time, and would certainly attain higher SPLs than either of the aforementioned units. I believe they were crossed over around 1200hz. Now days I believe ribbons and technology has progressed beyond the older AMTs advantages however I haven't heard any of the latest incarnations.
That's strange, I have a pair of DM-4 laying on the shelf...
So they sold you a pair recently?
reply "M&D has no plan to supply his drivers to the third party since our productivity is limited and these handmade drivers are barely enough for our own needs. I'm very sorry."
Don't quite see why as a potential customer I would be classed as a third party.. go figure
I'll take some solace from the Zaph Audio review
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I was inspired to make my own AMT´s as Beyma and Mundorf AMT´s did not even sound good enough to match my 8" drivers Only the Mark & Daniels AMT´s was matching the 8" drivers..
http://www.diyaudio.com/forums/full-range/156466-one-only-full-range-amt.html
When I evaluated Beyma, Mundorf and Mark & Daniels AMT´s the audio quality of the Mark & Daniels was superior to the two others...
Only the Mark & Daniels AMT´s was matching the 8" drivers..http://www.diyaudio.com/forums/full-range/156466-one-only-full-range-amt.html
When I evaluated Beyma, Mundorf and Mark & Daniels AMT´s the audio quality of the Mark & Daniels was superior to the two others...
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"They" are still making the original 'full-size' version..at $350 USD.........From reading the comments section there seems to be a quality control issue on these reissued units.
The website crashed my Adobe Player immediately upon jumping to this site.
_______________________________________________________Rick.......
The website crashed my Adobe Player immediately upon jumping to this site.
_______________________________________________________Rick.......
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I was inspired to make my own AMT´s as Beyma and Mundorf AMT´s did not even sound good enough to match my 8" drivers
http://www.diyaudio.com/forums/full-range/156466-one-only-full-range-amt.html
When I evaluated Beyma, Mundorf and Mark & Daniels AMT´s the audio quality of the Mark & Daniels was superior to the two others...
I can only surmise that there is plenty of myth and legend surrounding AMT's. I won't believe everything I read on 6 Moons in future.
And at the end of the day I can pick up a pair of good Hivi ribbons for 100 euros.
RayCtech, did these make it into production?
I do not expect they ever will.
I have now extended the range to four AMT drivers:
Bass, Midrange (revised original version), Tweeter and SuperTweeter.
I will complete some sets of a real fullrange AMT dipole based on the revised / new drivers and that may be it
I'm sad to hear this - but I do understand (I think). The undertaking of starting up a production run is very time consuming and expensive - and there is no assurance of success - or even regaining your development and start-up cost. In the end it is very possible to wind up with a storage unit full of unused parts and an empty bank account. Been there done that! Such risk are for the young - as they will have many years ahead of them with which to recover from the loss.
There are examples of success tho - look at RAAL and M&D.
Still - a shame to see such fine work and effort go for naught.
There are examples of success tho - look at RAAL and M&D.
Still - a shame to see such fine work and effort go for naught.
I do not expect they ever will.
I have now extended the range to four AMT drivers:
Bass, Midrange (revised original version), Tweeter and SuperTweeter.
I will complete some sets of a real fullrange AMT dipole based on the revised / new drivers and that may be it
What's stopping you making a few sets of speakers and putting them on the market? Even if they are expensive to produce it would seem people are prepared to pay if they are that good
There are other models of vintage Heils that are not dipoles........and are quite affordable.
I harvested these tweeters out of a pair of vintage 1970's ESS tempests that the neighbors left out for the trash man, and they are the most realistic sounding tweeters I've had in my system for cymbals, etc. They are presently being used with my Half Changs.
I've seen these around the web for around $75/pair or so.
I harvested these tweeters out of a pair of vintage 1970's ESS tempests that the neighbors left out for the trash man, and they are the most realistic sounding tweeters I've had in my system for cymbals, etc. They are presently being used with my Half Changs.
I've seen these around the web for around $75/pair or so.
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