AMT, anyone use them ?

bladesmith · « **on:** 27 Jan 2014, 04:28 pm »

Anyone ever listen to one ? Or know anything good or bad about ATM's in general ?

I was pondering the use of one in an OB speaker. (WOOFER/AMT/WOOFER or WOOFER/MID/AMT)

http://www.parts-express.com/ess-heil-air-motion-transformer-amt-tweeter--264-600

TrungT · « **Reply #1 on:** 27 Jan 2014, 04:55 pm »

Rainier

Brad · « **Reply #2 on:** 27 Jan 2014, 05:22 pm »

I'm working on a new OB using the AMT PRO4 tweeter.
I should have them up and going in the next month or so - I'll report back then, but I think it will work well.

GT Audio Works · « **Reply #3 on:** 27 Jan 2014, 05:27 pm »

In general I don't care much for ATM's...especially when they charge a fee !!!

But AMT's I have heard a few, they sounded quite good....but I have not heard them enough to comment on their character of sound.
What I can tell you is they are designed to go lower into the midrange better than a pure ribbon tweeter which will run into power and excursion issues. The pleated diaphragm is more efficient at coupling with the air in the mid frequencies , enabling it to blend better with a woofer. But like everything in the world there is a compromise, the diaphragm material and bonded conductor is thicker than a ribbon which will not have the same top end response as a ribbon. This is not necessarily a bad thing...just something to consider in your design process. The Ess Heil unit is quite pricey...the Dayton unit is less than half the price and seems to have more radiating area http://www.parts-express.com/dayton-audio-amtpro-4-air-motion-transformer-tweeter-4-ohm--275-094. These units also seem to like at least 2nd order networks..something I don't. The Dayton unit boasts a diaphragm thickness of .0005, I don't know if this includes the conductor traces or not...this is not thin. You would think it could handle a 1st order network. The ribbon tweeter I build, which is aluminum foil bonded to mylar is much thinner and I have no problem crossing it over with a 1st order network. Greg

bladesmith · « **Reply #4 on:** 27 Jan 2014, 05:32 pm »

TrungT, those are very sweet, no doubt. (jealous)

Brad,

Are you using it in a two way or three way application ?

Couldn't a pair of woofers be used with it ?

bladesmith · « **Reply #5 on:** 27 Jan 2014, 05:37 pm »

Quote from: GT Audio Works on 27 Jan 2014, 05:27 pm

In general I don't care much for ATM's...especially when they charge a fee !!!

But AMT's I have heard a few, they sounded quite good....but I have not heard them enough to comment on their character of sound.
What I can tell you is they are designed to go lower into the midrange better than a pure ribbon tweeter which will run into power and excursion issues. The pleated diaphragm is more efficient at coupling with the air in the mid frequencies , enabling it to blend better with a woofer. But like everything in the world there is a compromise, the diaphragm material and bonded conductor is thicker than a ribbon which will not have the same top end response as a ribbon. This is not necessarily a bad thing...just something to consider in your design process. The Ess Heil unit is quite pricey...the Dayton unit is less than half the price and seems to have more radiating area http://www.parts-express.com/dayton-audio-amtpro-4-air-motion-transformer-tweeter-4-ohm--275-094. These units also seem to like at least 2nd order networks..something I don't. The Dayton unit boasts a diaphragm thickness of .0005, I don't know if this includes the conductor traces or not...this is not thin. You would think it could handle a 1st order network. The ribbon tweeter I build, which is aluminum foil bonded to mylar is much thinner and I have no problem crossing it over with a 1st order network. Greg

Greg,
I have seen these (amt) used with other tweeters, using the amt, kind of like a midrange driver.
Can your ribbon tweeter be set up with two woofers ?

TrungT · « **Reply #6 on:** 27 Jan 2014, 05:37 pm »

It's not mine, sorry.

This's mine

jimdgoulding · « **Reply #7 on:** 27 Jan 2014, 05:40 pm »

Quote from: TrungT on 27 Jan 2014, 04:55 pm

Rainier

Damn, T, I think it's about time I ventured to Dallas and we dine together and listen to some tunes!

TrungT · « **Reply #8 on:** 27 Jan 2014, 05:45 pm »

I think John (InfernoSTi) has the Rainier and he's not too far from you Jim.
And you can ventured to Dallas, dinner is on me.

bladesmith · « **Reply #9 on:** 27 Jan 2014, 06:11 pm »

Quote from: TrungT on 27 Jan 2014, 05:37 pm

This's mine

TrungT,

What are those ?

GT Audio Works · « **Reply #10 on:** 27 Jan 2014, 07:22 pm »

Quote from: bladesmith on 27 Jan 2014, 05:37 pm

Greg,
I have seen these (amt) used with other tweeters, using the amt, kind of like a midrange driver.
Can your ribbon tweeter be set up with two woofers ?

Sure you can augment the upper range of an AMT with a ribbon tweeter....but my tweeter is a line scource like in a Maggie,
not suitable for an MTM arrangement.

Pete Schumacher · « **Reply #11 on:** 27 Jan 2014, 08:14 pm »

Quote from: bladesmith on 27 Jan 2014, 04:28 pm

Anyone ever listen to one ? Or know anything good or bad about ATM's in general ?

I was pondering the use of one in an OB speaker. (WOOFER/ATM/WOOFER or WOOFER/MID/ATM)

http://www.parts-express.com/ess-heil-air-motion-transformer-amt-tweeter--264-600

A far better AMT than that particular version can be had at Parts Express also.

http://www.parts-express.com/aurum-cantus-ast30100-aero-striction-tweeter--276-442

The AST can be run in dipole mode by removing the felt pad on the back.

Another fantastic AMT is the Beyma TPL150. It too can be run dipole by removing the rear chamber.

jimdgoulding · « **Reply #12 on:** 27 Jan 2014, 08:18 pm »

Quote from: TrungT on 27 Jan 2014, 05:45 pm

I think John (InfernoSTi) has the Rainier and he's not too far from you Jim.
And you can ventured to Dallas, dinner is on me.

It is my intention to come to Dallas soon to audition some DeVore's at Audio Concepts and the venerable Maggie 1.7's. I will definitely get in touch. You might care to join me. Hope so.

TrungT · « **Reply #13 on:** 27 Jan 2014, 08:39 pm »

Elac

mgalusha · « **Reply #14 on:** 27 Jan 2014, 08:48 pm »

I use the Beyma TPL-150H in by big two ways, crossover over at ~1200Hz, quasi 3rd order. I like them very much, smooth, high efficiency and extended. I won't post a pic, not open baffle.

Tyson · « **Reply #15 on:** 27 Jan 2014, 08:54 pm »

I can vouch that the TLP-150H is phenomenal - I've heard it in Mike's system and damn its good.

Brad · « **Reply #16 on:** 27 Jan 2014, 09:34 pm »

Quote from: bladesmith on 27 Jan 2014, 05:32 pm

Brad,

Are you using it in a two way or three way application ?

Couldn't a pair of woofers be used with it ?

I am going to use the AMT PRO4 crossed over around ~1900hz to a Hawthorne Sterling Silver 15" midwoofer
I'll have two Hawthorne Augie 15s per side, operating up to about 60hz

Brad · « **Reply #17 on:** 27 Jan 2014, 09:37 pm »

Pete/Mike,

Thanks for the links on the other drivers. They were a bit out of my price category during initial concept time, but either that Aurum or the Beyma would provide an upgrade path for me

mgalusha · « **Reply #18 on:** 27 Jan 2014, 11:11 pm »

Quote from: Brad on 27 Jan 2014, 09:37 pm

Thanks for the links on the other drivers. They were a bit out of my price category during initial concept time, but either that Aurum or the Beyma would provide an upgrade path for me

That is the big downside, they are quite proud of them.

solhaga · « **Reply #19 on:** 27 Feb 2014, 07:05 pm »

I built my own.

Membrane:

goes into a magnet structure:

that gets a wave guide:

that is mounted in a baffle together with three magnet mount AE TD15Ds:

Complete system: