Trying to collect some info on various lower priced, larger AMT tweeters. The Dayton and Aurum Cantus get mixed reviews from what I can see on line but no specific info on how they perform crossed lower.
I've tried the larger Dayton AMT Pro 4 and AMT 3-4. My conclusions were they sound a bit rough down low well within their recommended crossover points. The larger Pro 4 was a little worse than the 3-4. Using better dampening behind the Pro 4 helped considerably but didn't leave me feeling confident trying to employ it under 3k, even with steep filtering. It appears the rear dampening can make or break the performance.
I listened to the larger Aurum Cactus AMTs someone sent me to try (didn't see a model number on it). It sounded a bit better than the Dayton Pro4 but I couldn't cross it under 3k either without hearing a few distortion peaks on female voices using various HP filters, both active and passive at 2nd order to 4th order slopes. Once above 3.5k the Aurum Cantus was very good. The upper end sounded extended and effortless, even at eviction level SPLs. The matching between the same model tweeters was however poor with an audible difference in output and channel balance between both. That was rather disappointing after hearing their overall potential.
A long time ago, around the late 90s when AMTs just started showing up on the market, I worked on an R&D project with an independent speaker company in Europe which wanted to get into the AMT market building their own drivers for use in production speakers. It turned out the complexity of design, materials and tooling needed to build an AMT driver with the desired level of performance required more time and money than they were willing to spend.
In that design process, I tried a few AMTs, including models that Mundorf had at the time, which could be readily purchased. Those first gen AMTs also had problems with spurious lower frequency breakup.
Nowadays, the newer Mundorf AMTs sound much better, but they cost a fortune compared to a very good dome or even most true ribbons. I still use planars from Hivi which are pretty good crossed over higher. So far, I'm just not finding any AMTs which fall into that price bracket. The quality control appears to be hit and miss in that part of the market. That's unfortunately rather predictable.
Has anyone compared some of these newer, larger and less expensive AMT models yet and measured their performance?
I've tried the larger Dayton AMT Pro 4 and AMT 3-4. My conclusions were they sound a bit rough down low well within their recommended crossover points. The larger Pro 4 was a little worse than the 3-4. Using better dampening behind the Pro 4 helped considerably but didn't leave me feeling confident trying to employ it under 3k, even with steep filtering. It appears the rear dampening can make or break the performance.
I listened to the larger Aurum Cactus AMTs someone sent me to try (didn't see a model number on it). It sounded a bit better than the Dayton Pro4 but I couldn't cross it under 3k either without hearing a few distortion peaks on female voices using various HP filters, both active and passive at 2nd order to 4th order slopes. Once above 3.5k the Aurum Cantus was very good. The upper end sounded extended and effortless, even at eviction level SPLs. The matching between the same model tweeters was however poor with an audible difference in output and channel balance between both. That was rather disappointing after hearing their overall potential.
A long time ago, around the late 90s when AMTs just started showing up on the market, I worked on an R&D project with an independent speaker company in Europe which wanted to get into the AMT market building their own drivers for use in production speakers. It turned out the complexity of design, materials and tooling needed to build an AMT driver with the desired level of performance required more time and money than they were willing to spend.
In that design process, I tried a few AMTs, including models that Mundorf had at the time, which could be readily purchased. Those first gen AMTs also had problems with spurious lower frequency breakup.
Nowadays, the newer Mundorf AMTs sound much better, but they cost a fortune compared to a very good dome or even most true ribbons. I still use planars from Hivi which are pretty good crossed over higher. So far, I'm just not finding any AMTs which fall into that price bracket. The quality control appears to be hit and miss in that part of the market. That's unfortunately rather predictable.
Has anyone compared some of these newer, larger and less expensive AMT models yet and measured their performance?
Here in China the (grey) market is flooded with them (often branded Golden Ear) but typically small. My first DIY "HeilEve" used boutique 1in by 2in AMT after first trying and returning a smaller one due to both QA and extension issues. I was very happy with the upgrade (paired with ~90dB honeycomb after Eve Audio SC-205 but series-1st-order ~2.5khz 7L tapered TL) however I didn't buy another pair. (Found Adam F5/F7 AMT instead.) A Hong Kong net-friend did clone my TL cab and used the next size boutique AMT (only half the price of Satori TW29R...), with active XO.
Size matters.
Size matters.
The Dayton aren't bad but it depends on how you use them. The ATM Pro 4 are PA tweeters. I suspect they used a thicker foil for a higher power rating and ruggedness. The foil material - Kapton - is another hint that's probably been a design choice despite Kapton being too stiff.
That's the case for all dipole AMTs.
Aurum Cantus doesn't have AMTs in their program, I only know of ribbons. Low crossover points are not what they like and if it is too low, you can easily damage/stretch out the ribbon by it. Even a single sweep from too low can do that.
Thanks guys. I suspected the Kapton choice and thought the membrane was too thick for sake of durability. I’ve heard the Adam AMTs in their more expensive line and they were good as well. How would one get those separately as a bare driver?
@ICG These two AMTs are sold by Parts Express under the Aurum Cantus brand.
https://www.parts-express.com/Aurum-Cantus-AST2560-Aero-Striction-Tweeter-276-440
https://www.parts-express.com/Aurum-Cantus-AST25120-Aero-Striction-Tweeter-276-446
These are both excellent drivers. Far better than any other generic AMT I've heard and very close to lower end Mundorf. Not cheap in comparison to other cheaper models.
@ICG These two AMTs are sold by Parts Express under the Aurum Cantus brand.
https://www.parts-express.com/Aurum-Cantus-AST2560-Aero-Striction-Tweeter-276-440
https://www.parts-express.com/Aurum-Cantus-AST25120-Aero-Striction-Tweeter-276-446
These are both excellent drivers. Far better than any other generic AMT I've heard and very close to lower end Mundorf. Not cheap in comparison to other cheaper models.
These are indeed AMTs. The reviews seem to be excellent though I can't say anything about them, I have not seen any measurements yet. Their prices seem to be much more reasonable than the Mundorf. It's definitely worth trying them I think.
I heard the smaller one in a 3 way crossed 2.8k 3rd order. Didn't have any of that honk or abrasive lower treble and played very clean at any volume, very close to a true ribbon. I owned the original Raven R1 ribbons from the late 90s sold by Orca (long gone by now). Those had the cleanest top end I've ever experienced from a real ribbon. The transformers they used were better than Raal and their performance is a benchmark by which I judge all other planar tweeters. If the cheaper Asian AMTs weren't so fragile, they'd be a great deal. For a driver that should be able to play very low (<1500 hz) the durability is a big issue. At least its easy and cheap to replace ribbons when they blow, but with an AMT the expense goes into most of the membrane which isnt user serviceable.
And just for giggles, I tried a pair of the Beyma TPL150s. They were disappointing. Compared to other planars, they had more junk going on under 3k than any other AMT, even the big Dayton. Perhaps the WG helps with this, but I never felt they were on the same level as a higher end compression driver on a good WG. The 18sound NSD1095N on the B&C ME45 sounded superior to the TPLs above 3k.
That's a well-known issue, you just have to extend the back chamber and damp it. After that they perform flawlessly. That's not just a Beyma thing, you have to be prepared to make some kind of back chamber modification to any of the big AMTs, even Mundorf.
I've tried the Beyma with various dampening strategies and they still have that thicker low mid congestion. The TPL75 was a little better but not good enough. The Mundorfs come in chambered and open versions. The moving elements are the same on a given model, just the chambering is the difference and its clearly not that sophisticated of a design. Many planars suffer from this too, being open. The Hivi planars are known for their congested upper mids and respond well to modification.
Have you looked at the relatively new Dayton Audio AMTHR-4?
I'm working on something now and can probably post distortion measurements in the next 7-10 days.
I'm working on something now and can probably post distortion measurements in the next 7-10 days.
Javad built a 3 way using the Dayton AMTs for both mid and tweeter. I don't know what or how he did it. I believe the build is on facebook.
Some of the best, most open sounding speakers I've listened to.
I liked the Adam AMT. I think this is a custom unit built by Eton but I'm not betting my life on that. All they're other drivers used to be Eton.
Some of the best, most open sounding speakers I've listened to.
I liked the Adam AMT. I think this is a custom unit built by Eton but I'm not betting my life on that. All they're other drivers used to be Eton.
I think Adam builds or has someone else build their AMTs. This is why I think so:
- their AMTs are quite different (and a lot simpler / more cheaply made) than the Eton ER4
- LPG, the company behind the Eton brand, went belly up about three years ago and Adam continued churning out their speakers apparently unchanged
- I kind of remember having seen some snippet or video about AMT production at (for) Adam
I heard the TPL150 in the horns (Hawthorne?) as Jim Griffin built his active open baffle 3ways xovered at 800, and I thought they sounded quite good, but too neutral if I had a proper adjective.
The Dayton/Tianle models are just okay for the most part. Being the AMTHR is different material, I don't think Tianle makes those.
I really prefer the Airborne/Hygaeia models over the Tianle, and they are what Legacy uses. The 4001 and 5002 are both really good units. The 4001 will play lower than the 5002, which is only good to about 3.5k. The 20021 really is not that great for more than a super tweeter. (The 4101 is a really slim and long super tweeter as well, good for 8k+, but this one is not an AMT.)
The Mundorfs are so expensive, and I don't feel sound any better than the Airbornes. I've heard several in commercial designs.
The Dayton/Tianle models are just okay for the most part. Being the AMTHR is different material, I don't think Tianle makes those.
I really prefer the Airborne/Hygaeia models over the Tianle, and they are what Legacy uses. The 4001 and 5002 are both really good units. The 4001 will play lower than the 5002, which is only good to about 3.5k. The 20021 really is not that great for more than a super tweeter. (The 4101 is a really slim and long super tweeter as well, good for 8k+, but this one is not an AMT.)
The Mundorfs are so expensive, and I don't feel sound any better than the Airbornes. I've heard several in commercial designs.
This goes well with something I posted in another thread. While the expensive AMTs can be very good, the less expensive one's are a duck shoot. On the other hand ring radiators and dome's have a very wide and excellent set of choices in the $50-$150US range.
As for gunk under 3K with Mundorfs, sorry I measured distortion ages ago here in this forum, and they didn't suffer as claimed, even when pushed. Perhaps this is model specific. Also, having now owned them and some domes and ring radiators I'd probably tell the me of 10 years ago to go with domes, save the money and put it towards a plate amp. 😉
As for gunk under 3K with Mundorfs, sorry I measured distortion ages ago here in this forum, and they didn't suffer as claimed, even when pushed. Perhaps this is model specific. Also, having now owned them and some domes and ring radiators I'd probably tell the me of 10 years ago to go with domes, save the money and put it towards a plate amp. 😉
Buy the desired replacement AMT's that is available from different sources, like:
https://reconingspeakers.com/?s=Adam+audio&post_type=product
https://audiodesign-parts.com/collections/adam-audio-parts
As for unmentioned AMT's, Fostex released the T360FD, the previous year.
And there is the japanese FAL(Furuyama Audio Lab) AMT, but does not fit in the budget category.
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If you are talking about Beyma TPL150 (not TPL150H horn), by "low mid," are you talking about the proper vocal low mid, e.g. 250-500Hz or the low mid range of the TPL150 extension, i.e. 1.5-2kHz?