I wouldn't trade them for anything... 😀hifi said:
planet10...you woudn't happen to remember which version of the diaphram the Heil you tested used? I realize that the curve may vary somewhat from one version to the next, but are all the ESS Heil's 'about' the same low impedence (3 ohms and change)?
EchoWars said:
The only ref i have is the pictures in my Planet_10 HiFi Audio Vendors Bazaar thread...
dave
I used to work for a large Hi-Fi dealer in the Chicago burbs back in the early 70's that was an ESS dealer. We did alot of expereimntation with them including placing a small baffle behind the AMT to slightly delay the rear wave. This made a noticable improvement in the lower mids. Has anyone else here tried this?
Mark
Mark
Not with mine...I'm running 2-way with the Heils crossed over at about 2500Hz.
I love the Heils, but the Dynaudio's I have for the bottom end sound much better doing midrange duty from 2500Hz down. I know the Heils can go lower, but I've never cared for the sound of them in the hardcore mids (800 to 1800Hz). IMHO, they don't 'come alive' till 2K or so.
I love the Heils, but the Dynaudio's I have for the bottom end sound much better doing midrange duty from 2500Hz down. I know the Heils can go lower, but I've never cared for the sound of them in the hardcore mids (800 to 1800Hz). IMHO, they don't 'come alive' till 2K or so.
EchoWars said:
Are you using heil 10" drivers or do you have something smaller in order to crossover that high?
Homebuilt cabinets, with two Dynaudio 20W75's in each. The stock cabs used 12" Utah woofers that were horrid (these began life as stage monitors). 😉
Heil AMT's - Question for Mark A. Gulbrandsen
This is an old thread, so it's a bit of a long shot! But Mark if you are still around could you please describe what size, type and placement of small baffle you used to get the Heil AMT to sound better in the mids ??
Having just acquired a decent s/h pair of 1977 vintage ESS AMT-1A's I am surprised at how good they are overall (after all these years the speaker is not at all dated sounding and the bass is gutsy to say the least), and this is in the context of someone who's used to Accuton+Ravens/Seas Excel magnesiums/ESLs and Fostexes!.
With respect to the slight lack of body in the AMT midrange, I have experimented with trying to get it to sound more natural/warmer and have found that Mark's earlier suggestion of placing a small baffle behind the AMT treble unit does indeed seem to work. All I have done is place a 4" x 8" x 2" paving brick about six inches behind the AMT driver, and it has the effect of giving more body to the upper mids without sacrificing the airiness of the AMT driver. I suppose this sends some of the backwave towards the front thereby increasing the strength of the midrange.
I also tried closing off the rear end of the AMT unit with a piece of MDF and dacron stuffed into the rear cavity as suggested elsewhere, but this seems to have a negative effect on transparency so I don't favour it.
Anyone else tried similar tricks and Mark if you're still around please comment ...
Regards,
Steve M.
This is an old thread, so it's a bit of a long shot! But Mark if you are still around could you please describe what size, type and placement of small baffle you used to get the Heil AMT to sound better in the mids ??
Having just acquired a decent s/h pair of 1977 vintage ESS AMT-1A's I am surprised at how good they are overall (after all these years the speaker is not at all dated sounding and the bass is gutsy to say the least), and this is in the context of someone who's used to Accuton+Ravens/Seas Excel magnesiums/ESLs and Fostexes!.
With respect to the slight lack of body in the AMT midrange, I have experimented with trying to get it to sound more natural/warmer and have found that Mark's earlier suggestion of placing a small baffle behind the AMT treble unit does indeed seem to work. All I have done is place a 4" x 8" x 2" paving brick about six inches behind the AMT driver, and it has the effect of giving more body to the upper mids without sacrificing the airiness of the AMT driver. I suppose this sends some of the backwave towards the front thereby increasing the strength of the midrange.
I also tried closing off the rear end of the AMT unit with a piece of MDF and dacron stuffed into the rear cavity as suggested elsewhere, but this seems to have a negative effect on transparency so I don't favour it.
Anyone else tried similar tricks and Mark if you're still around please comment ...
Regards,
Steve M.
Memories of AMT-1
I haven't posted in ages, but this thread inspired me. I have a pair of AMT-1 air motion transformers which I acquired after having built DIY versions based on an old article from Audio Amateur. The home builts were OK, but the real thing is really nice.
I had the pleasure of visiting with Oskar Heil several times before he passed on. He had some wonderful stories, including how he invented the first transistors, and then due mostly to world war II lost credit to Bell Labs. When I visited him back I think in the early 90's or late 80's, he was working on a new improved version of the air motion transformer. The results were so much better than the AMT-1's, I wish they had been produced for us to enjoy. I'll have to see if I have any notes from those meetings. He also had a very interesting passive radiator cabinet design for a woofer to complement the air transformer.
Anyway, thanks all for the fascinating thread. I'll have to resurrect my AMT-1s and see how they compare to the Beveridge III's I am now using for my main system.
I haven't posted in ages, but this thread inspired me. I have a pair of AMT-1 air motion transformers which I acquired after having built DIY versions based on an old article from Audio Amateur. The home builts were OK, but the real thing is really nice.
I had the pleasure of visiting with Oskar Heil several times before he passed on. He had some wonderful stories, including how he invented the first transistors, and then due mostly to world war II lost credit to Bell Labs. When I visited him back I think in the early 90's or late 80's, he was working on a new improved version of the air motion transformer. The results were so much better than the AMT-1's, I wish they had been produced for us to enjoy. I'll have to see if I have any notes from those meetings. He also had a very interesting passive radiator cabinet design for a woofer to complement the air transformer.
Anyway, thanks all for the fascinating thread. I'll have to resurrect my AMT-1s and see how they compare to the Beveridge III's I am now using for my main system.
ESS AMT-1
Do anyone have an idea on the best way to cross the AMT tweeter.
I have an old schematic that indicates 18dB/oct for the tweeter.
Also in the schematics are included brilliance an mid controls (±6 dB)
Thanks
Do anyone have an idea on the best way to cross the AMT tweeter.
I have an old schematic that indicates 18dB/oct for the tweeter.
Also in the schematics are included brilliance an mid controls (±6 dB)
Thanks
What are you crossing it to?
I cross mine at about 1250, with a 48db/oct filter to a pair of 8s and the sound is great. YMMV
I cross mine at about 1250, with a 48db/oct filter to a pair of 8s and the sound is great. YMMV
I cross my ESS at 2250 Hz with a 12dB/oct.
I use them with 2 HDS205 Peerless woofers. So I get around 95dB
I use them with 2 HDS205 Peerless woofers. So I get around 95dB
ESS AMT Monitors-Got a pair...Any info?
Hello, just picked up a pair of ESS AMT Monitors from a friend. I don't know if I can talk my wife into allowing them in the house! About 4 feet tall and frankly, pretty ugly burgundy tweed fabric and tired Oak veneer. My question is this...should I keep them or sell them? They sound excellent and other than the obvious aged cabinets are in very good original condition. I know the Heil tweeters go for about $300 a pair on eBay but think it would be a shame to tear up the boxes if they are desirable to someone as is. I am a fan of vintage US made HIFI and don't want to disturb them, but maybe the only real value is in the HEIL tweeters. Anyways, hope I am not being too much of a pain to post here, thanks for any input you may have...
Hello, just picked up a pair of ESS AMT Monitors from a friend. I don't know if I can talk my wife into allowing them in the house! About 4 feet tall and frankly, pretty ugly burgundy tweed fabric and tired Oak veneer. My question is this...should I keep them or sell them? They sound excellent and other than the obvious aged cabinets are in very good original condition. I know the Heil tweeters go for about $300 a pair on eBay but think it would be a shame to tear up the boxes if they are desirable to someone as is. I am a fan of vintage US made HIFI and don't want to disturb them, but maybe the only real value is in the HEIL tweeters. Anyways, hope I am not being too much of a pain to post here, thanks for any input you may have...
Re: ESS AMT Monitors-Got a pair...Any info?
Hello, I have a pai of bookshelf ones (only one woofer with passive radiator in the back). IMHO the woofer is definitely cheap if compared with the Heil tweeter.
I'm trying to rebuild the speaker keeping the tweeter and throwing away the ugly woofer.
Remember, a big box usually sounds better than a small one. You only have to face the SAF (Spouse Acceptance Factor).
essjohn said:
Hello, I have a pai of bookshelf ones (only one woofer with passive radiator in the back). IMHO the woofer is definitely cheap if compared with the Heil tweeter.
I'm trying to rebuild the speaker keeping the tweeter and throwing away the ugly woofer.
Remember, a big box usually sounds better than a small one. You only have to face the SAF (Spouse Acceptance Factor).
JohnL said:
Hi JohnL,
I'm trying to contact you regarding your speakers with ESS tweeters. I'm considering buying a pair of AMT1s from ESS and would like to possibly mate them to W22EX for midrange and RS225s for bass. I'm also very interested in your design. I've pmed you at htguide.com too- but it appears you haven't seen my message yet. Would like to know very much what you think about the AMT1 and how they integrate with the RS225s. I'm astounded by the clarity of the Heil Motion and right now I'm not sure if anything compares- even ER4! Thanks and hope to hear from you soon.
Jed
JohnL said:
No, I think you may have to send the attachments to me through a PM (here)- unless the files are too big for that feature too. I just sent you an email explaining the situation I'm in. I think PM should work. Thanks and looking forward to seeing your designs.
Regards,
Jed
ESS AMT-1a Air motion transformers
I came across this forum while wondering what to do with a pair of these units: I pulled them out of a pair I'd bought new, loved and listened to for years, the bass driver cones eventually got blown out...(still have those if anyone wanted them too 😉 , and life changes never let me get back to using the parts for anything...
So now I'm aware these things actually have some intrinsic value to audiophiles out there, is anyone on this forum still looking for a pair? Would $200. US and you pick up the shipping be out of line?
cheers,
Brett
I came across this forum while wondering what to do with a pair of these units: I pulled them out of a pair I'd bought new, loved and listened to for years, the bass driver cones eventually got blown out...(still have those if anyone wanted them too 😉 , and life changes never let me get back to using the parts for anything...
So now I'm aware these things actually have some intrinsic value to audiophiles out there, is anyone on this forum still looking for a pair? Would $200. US and you pick up the shipping be out of line?
cheers,
Brett
Hi Brett could you email me at william_backhouse(at)hotmail(dot)com. I may be interested depending on postage (ie how heavy are they).
Once, for one of my customers I built an open baffle triamp system with AMC-1 on top, Audax PR170MO as a mid, and Titanic subs (also open baffle).
It had a very good integration between top and mid, with IIRC, crossover points at 225Hz and 1500Hz.
Although AMC-1 can go as low as 800Hz, you need a high order crossover to avoid low freq. overloading. With continiously variable 4th order electronic crossover I found 1200-1500Hz is a lower limit, when they start feeling "happy".
It had a very good integration between top and mid, with IIRC, crossover points at 225Hz and 1500Hz.
Although AMC-1 can go as low as 800Hz, you need a high order crossover to avoid low freq. overloading. With continiously variable 4th order electronic crossover I found 1200-1500Hz is a lower limit, when they start feeling "happy".
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