| old beginner needs help with ESS AMT conversion - Click HERE for Original Thread |
| robin brown |
In 1975, I bought a pair of ESS AMT 1's (Heil driver, 12" woofer and passive radiator) and never looked back. They're still working fine, and but for replacing the woofer / radiator foam, they're solid. Love the sound.
BUT they're huge and ugly and the bass is marginal.
I'd like to use the Heil drivers in new enclosures, maybe with a separate midrange boxes to set nearby, maybe with bass commodes / subwoofers to carry the rest of the spectrum. Or minimally, I'd like to build a better cabinets with better bass / mid components. Getting them smaller and prettier would be real nice. With the right speaker plan, I'll change the electronics to suit.
I need beginner's advice, having not done any electronic DIY projects in over 40 years. While I can probably rebuild a 5-tube AM radio or push-pull amp dead drunk in the dark, I know virtually nothing about modern techniques or supply sources--having left this world when Heathkits walked the earth. With instructions, though, I can build anything--and the cabinet-making is a piece of cake.
Minimally, I'll need crossovers and mid / bass speakers--and the lore to hook them up.
I'd appreciate advice on whether this is worthwhile, and if it is, what I might buy / build. |
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| el`Ol |
| In Japan the AMT/Furuyama combination with a flat crossover is very popular. But I never listened to it, I think Furuyamas are not sold in Europe. And the price for the units is high. |
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| jmateus |
A few years ago I had a similar dilema, to eliminate these bulky speakers but saving the tweeters which I think are fenomenal.
I choose to build a pair of MTMīs around the Heil tweeter. The
result was very interesting, to put it mildly, the quality of the
MTM is excelent, only limited by the quality of the double woofers,
which are Bravox, a brasilian brand of speakers not very well
know in this country but really well made.
If interested I can give you details of these speakers which I use
even today.
You can judge by yourself, the picture is here. |
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| JohnL |
I am using AMT-1 tweeters on top of sealed ~80 liter box with 2 Parts Express Dayton Reference RS-225s. The filter is a Cauer Elliptical (LR8/Jon Marsh style) and the sound is just plain heavenly. 80 Liter boxes are big, but thinner than the old AMT1 cabinets. I think the AMT1s blend well with a pair of 8s. I have seen some other designs like this (AMT1 w/2 Seas L22s, Focal 8Ws, Scan Speak 21Ws). I would be happy to share my crossover diagram if you want to go this route.
John |
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| jmateus |
This is the ESS crossover Iīm using. It has provision on the passive side
for the AMT 1 and whatever woofers youīre using (with some mods).
As a bonus it has an active filter for the subwoofer at 95 Hz.
I think part of the good sound that comes from those speakers is due
to the factory crossover that I had a chance to buy three years ago.
Out of curiosity could you please supply me the schematic of yours
just to see how different is it from mine?
Thanks |
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| JohnL |
Umm... well. That appears to be an active (line level) crossover. I'm not exactly sure what you mean by "It has provision on the passive side for the AMT 1 and whatever woofers youīre using".
My crossover will be substantially different considering it is a passive (speaker level) crossover. Having said that, active crossovers are generally thought of as being better than passives, all things being equal.
If the crossover is somewhat adjustable, I would say this: Set a budget for how much you want to spend on a set of drivers. Unless you get something of very high efficiency, expect to buy 4. I would recommend a pair of 8's on either side. Many people here could argue the virtues of any particular brand, but find something you like in your price range. Peerless, Vifa, ScanSpeak, Seas, Focal, Eton and PHL are all good brands. In most cases, expect to get what you pay for. Some will have a different sonic signature than others. A $100 pair of Peerless drivers can sound good, expect that a $1000 pair of Skannings will probably sound better (given the right amount of tuning). I personally think the Parts Express RS225s are a real deal at their price.
Once you have the drivers, it's not too difficult to figure out the right size box. Most vendors can recommend the appropriate sized box for any given woofer, of course double it if using 2.
The last part would be setting the crossover up. If it's an adjustable crossover, shoot for a xover point around 1000-1500 depending on the woofers you use. Listen to it and see what sounds best to you.
The picture below is somewhat representative of what I have done, however that one is using Focal drivers. |
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| inertial |
Hi Jmateus,
I am not sure, but " the black box" remember me the original ESS
crossover of the Transar ATD 2 sistem. Am I wrong?
regards |
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| jmateus |
Yes, I believe it was used with that ATD system, however I bought
it separately sometime after I had the ESS speakers.
It is a crossover especially designed for the Heill tweeters, and
it features an active section for a subwoofer that gives it a
certain versatility. The rest of the crossover is passive, again for
the tweeter. Itīs a nice piece of equipment, they donīt make these
things anymore, Iīm sure.
John L
Among all the name brands of drivers I still think the Parts Express
private brand Dayton has a lot of good drivers that represent a
very good value. Iīve used several in the past, I still remember the
excelent tweeter they had #275-070 (out of the production line now)
but an excelent value for the money.
Iīm the type of person that is always looking for good buys no matter
the name brand and, sincerely, Iīve found excelent returns for
my money, a good example of this is the Bravox drivers that I use
in my MTMīs along with the Heill tweeter. It was a sale item at
Parts Express.... |
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| inertial |
(sorry for my english)
Hi jmateus,
I am very surprised. Look at the rear of the box,please. If there is writed "transar heil out" on the two cannon connectors you have purchased a RARITY!
Maybe you not remember the dipole heil woofer (4 membranes) but (maybe)this is his dedicated crossover .
In this case ,unfortunately, the totally different modality of emission
of the different drive units cause impredictable results.
Maybe the passive section it was modified , or maybe you are very lucky!! :)
Many years ago I had a transar atd2 system (used) without crossover.
Now you find it! If you could imagine the difficult to find the schematic
and duplicate it............
Ah , very strange world! :)
regards |
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| jmateus |
It is indeed a very strange world.... I had no idea when I bought this
crossover I would buy a true rarity and in fact it was something that
I had to figure out in view of the fact that I had never seen one like
that.
I opened it up and try to follow the design as best as I could and I
came up with this little drawing even to help myself when I wanted
to do any connections to my speakers. I needed right away because
of the tweeter and also because the crossover that was in the box
was very primitive as well as the woofer and the passive radiator,
all junk...
Made new speakers (which I publised the photo) taking advantage of the excelent tweeter and I donīt regret it because the sound is
quite good...
I realized this is not the crossover device for my speakers but I
dealt with it, changed a few caps (the existent ones were ****) and
a couple of coils to suit my woofers, but the high section is untoutchable
it controls the Heil tweeter and I donīt want any discrepancies.
But for you to realize what the whole thing is all about here is the
layout of the connections, quite complicated, thank you.
Rarity? Itīs possible, at least Iīve never seen one like this.... |
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| jmateus |
I couldnīt upload the sketch I made with the connections. Letīs see
if it goes now... |
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| inertial |
Hi Jmateus,
I was right! ;)
Zoom
Zoom
regards from twenty years ago! |
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| jmateus |
Thanks for the pictures, itīs quite a set up what you got there, very
nice.
One thing I forgot to ask you was what do you mean by four membranes? Is that something in your speakers? Itīs because Iīm not
familiar with that nomenclature, but it might be something very
proprietary of ESS.
In any case I could not make nothing familiar to me out of the pictures
except, of course, the tweeter and the black box. |
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| inertial |
I'am sorry, I have severe problem with english.....
The Heil woofer was exlusively ESS device by Dr.Oskar Heil for this loudspeaker system called "transar". The four lexan diaphragm is connected by four carbon "tubes"(pipes) driven by a conventional coil+ magnet at the base ( the square element).
The system was sold complete .
Previous system, the original Transar was five diaphragm woofer
(current-driven) with a bigger flat baffle and without Subwoofer (1979 if I well remember).
I am wondered what ESS (on his website) do not show this historycal
system. Maybe was a "sales-flop"? ;)
P.S. the Photo are by SUONO (italian magazine1986)
regards |
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| el`Ol |
| Seems to be something like an ancestor of the Tymphony LAT. |
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| inertial |
Hi el'Ol ,
When I asked to Tymphany the same thing they answered so :
"Unlike the Heil,the diaphragms are not attached. Our moves the air like clapping your hands togethar."
I wanted a technical drawing to understand very well but this was not possible (comprensible ) .
They are a drivers manufacturer who sells to others manufacturers.
Waiting.................:)l |
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| tomtt |
Originally posted by inertial
The Heil woofer was exlusively ESS device by Dr.Oskar Heil for this loudspeaker system called "transar".
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seen a pair of the woofers in a store once (late 1980's)
owner wanted just under $600 |
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| inertial |
A pair of raw (nude) woofers "alone"? Used?
Oh, very strange................but possible .
I remember the italian dealer asked 2500 USD for one woofer for original spare parts 5 years ago!!! |
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| tomtt |
Originally posted by inertial A pair of raw (nude) woofers "alone"? Used?
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no, they were new!
owner claimed he traded for a tape deck |
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| Transar-Fan |
My first posting ever in the web!!!!!
My ESS-Transar ATD 2 is still going strong and beautiful ...
I bought them in germay in a HiFi-Shop 20 years ago. They are priced 10 000 DM... Why more than twice this price now in Italy? I'm not shure if this are brandnew items?
Never heard that replacement parts are available for the HEIL-woofer, only for the tweeters. Can anybody tell me were to get then, if it's true?
To Tymphany:
I visited their site:
Their principle is not to move diaphragms fixed to one driver against fixed plates on the housing but instead two opposite mounted drivers moving diaphrams (or plates) aigainst each other (every second plate is fixed to the opposite driver)
The principle is like clapping hands by both: Tymphany and HEIL-woofer!!!!!
Nevertheless i will try to get the biggest tymphany they produce for testing purpose: (Perhaps replacing the sub-woofer of my ATD to get an all 'clapping hands principle'- LS'.
So long i have no price , no dealer for it in germany!!
P.S Are there other Transar-owner listed? Found none... |
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| el`Ol |
| I asked them and they say the first LATs will come out in November, but only to OEM customers, so I guess we`ll have to wait for a half year. |
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| Tad |
| JohnL - I am planning a build using AMT's and 2 RS Dayton woofers per side and steep slope (CE - LR8) type filter. I would be very interested in your diagram and any other insight you may have with this combination. Thanks. |
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| JohnL |
Here's the diagram of the crossover I've been using for the past couple years. The RS225s are in a sealed box, the q of the box is around .6 if I recall. They sound pretty good, and I'm even using electrolytics for the two big shunt caps.
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| dickmorgan22 |
John:
Thanks for posting your crossover for the speaker in question. I posted some questions on another thread about a similar design that I am doing, and maybe you can save me some time......
Did you ever measure this speaker, or was it an analytic design? I am having a devil of a time coming up with a voicing for my rendition (different mid bass drivers) and am curious what relative level you came up with between the heil and the woofers at the crossover point. Flat is not right, of course, since the heil is a dipole. Where did yours end up for relative sensitivity of the heil and the woofers?
Dick M |
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| Tad |
Thanks for the diagram JohnL. I noticed that you are there is no
capacitor in series with the second inductor on the AMT's.
Have you tried this approach? (and thanks for being the keeper of
AMT information!) |
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| JohnL |
Hi guys
Dick: I saw your other post and had meant to get back to you there. Sorry, the holidays have kept me very busy. To answer your question, yes I measured it, but it was before John K had written his instructions on how to measure a dipole. When measured from 1 meter the AMT was a little hotter than the woofers. I don't have a plot in front of me, but I think it was 2-3 db up. I should measure the darn things properly sometime, but hopefully I'll be replacing them with full dipoles soon. That's another adventure that's gone on longer than expected. ;)
Tad: No, I never tried putting a cap on there. I spoke a bit with Jon Marsh from the 'other' forum to get the CE thing right. This sounded the best out of the few other designs I tried.
No problem being the info corner for the AMT's, I have no problem touting something I believe in. |
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| dickmorgan22 |
| quote: | Originally posted by JohnL
Hi guys
Dick: I saw your other post and had meant to get back to you there. Sorry, the holidays have kept me very busy. To answer your question, yes I measured it, but it was before John K had written his instructions on how to measure a dipole. When measured from 1 meter the AMT was a little hotter than the woofers. I don't have a plot in front of me, but I think it was 2-3 db up. I should measure the darn things properly sometime, but hopefully I'll be replacing them with full dipoles soon. That's another adventure that's gone on longer than expected. ;)
Tad: No, I never tried putting a cap on there. I spoke a bit with Jon Marsh from the 'other' forum to get the CE thing right. This sounded the best out of the few other designs I tried.
No problem being the info corner for the AMT's, I have no problem touting something I believe in. |
Thanks for the reply John. I confess that I have not read John K's paper on dipole measurement, and this needs to be my first stop. I had assumed (and may yet still!) that the AMT will have some interesting polar properties, but its not like a dipole mid or woofer since it has what appears to be an effective baffle width of about 12" (BTW, never stick a steel ruler into an AMT!), and the real dipole behavior will be below the 1200 Hz crossover point I have now.
The really puzzling part is that the power response of the AMT is clearly not like a dome or ribbon tweeter at all, and that simply doing a level match at the crossover point is NOT the right thing to do here. I have no science to descrbe this, but when I level matched the speaker from the front at 1 meter, it was way too bright. As I adjust this by ear, I got all the way to -12 dB before it was obviously off. After listening and tinkering, I arrived at about -3.5 dB attentuation from the natural sensitivity. When I measure this the same way I measure a monopole (Gated), it looks like about an 8 dB difference between my woofers and the tweeter (The woofers are much higher), although being an MMT with a pair of 8's, its tough to ensure equalized distances AND stay on axis for the tweeter.
This math works with the estimate. I have heard that the Heil is about 101 dB, although the gated 1 meter measurements do not support this, since, its a dipole! I do know that my woofers are 95 dB each, yielding a raw 101 dB. With 3.5 dB of baffle step and 3.5 dB tweeter attenuation, it all makes sense. Except that pesky measurement showing an 8 dB step down at the crossover point.
The other pesky point for me is your crossover. I modeled your highpass section with my measurements, and your filter and mine are virtually identical except that you have about 7 dB of attenuation. If the Heil IS a 101 dB driver, then yours will be matched to a pair of RS-225's.....with zero baffle step compensation. Yours should have been about 10 dB down???
All this leads me back to the measurement not looking right. Its also possible that my AMT is not 101 dB at all, or maybe none of them are! Anyways, I was hoping to see someone else with a set of measurements that look like mine, or tell me why mine are wrong. Perhaps John K will do that for me.....again.
Thanks again,
Dick |
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| MeanGene |
| Hello All, very interesting reading. I am currently using 4 ESS AMt3's in a 5.1 Home Theater configuration. I would like to build an AMT driven center channel. I am thinking of using two Seas Excel 7" drivers to sing along with the Heil. I am looking for a couple of the AMT to complete the parts gathering process. If you find any good working units, please let me know. Any suggestions on everthing from box design to xover is welcomed. |
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| Isight |
| How do I build a crossover like Johns? |
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| hndaaudio |
I am thinking about matching the large heil's with a pair of audax 8" woofers at 1500 hz but am stuck on the best slope to use.From what I have read,24db will cause insertion loss(can anyone tell me what the audible effect is ?),18db can cause lobing(does this also apply to the heil's ?) and 12db may not be steep enough.Also what is the best filter type for this setup ?
Maybe this would all be simplified by crossing over higher,but I don't want to give up any more of the heil's definition than necessary,just high enough to "relax" them.
Any help you ESS fans can supply is greatly appreciated. |
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| dickmorgan22 |
| quote: | Originally posted by hndaaudio
I am thinking about matching the large heil's with a pair of audax 8" woofers at 1500 hz but am stuck on the best slope to use.From what I have read,24db will cause insertion loss(can anyone tell me what the audible effect is ?),18db can cause lobing(does this also apply to the heil's ?) and 12db may not be steep enough.Also what is the best filter type for this setup ?
Maybe this would all be simplified by crossing over higher,but I don't want to give up any more of the heil's definition than necessary,just high enough to "relax" them.
Any help you ESS fans can supply is greatly appreciated. |
I spent several months trying to do a design similar to the one you propose. Tried, because ultimately I surrendered in frustration. The Heil is a superb tweeter, no question. It is however, a dipole, and this causes some very unusual power response characteristics to appear that are very much room dependent. My story is a long one, but let me offer a few tidbits for consideration.
- I started with an MMT, Heil mounted on top. Use this design. The MTM style had way to many compromises
- Set up the woofers in a bipole configuration - one front, and one rear firing. After talking to Planet10 on this for a bit, he came up with this approach, and it has its merits. I have not tried it (yet), but there is no doubt that this is the way to go.
- I tried all the slopes (I have an electronic crossover I used for auditioning), and a third order slope worked best for my box. The Heil does not seem to care, but the woofer will. More importantly, the power response in the 1 - 2 KHz range is critical. This is where the woofers are finishing their baffle step transition, and where the Heil is starting. Slope in this area is critical, and will depend upon the shape of your cabinet. In a bipole configuration, this will likely change.
- Because of the power response a flat measurement on axis does NOT sound right. I wound up padding mine a lot to prevent the speaker from tearing my head off, despite some very nice looking on axis measurements. Check out John K's website for a releveant, but not definitive analysis of dipole power response issues.
- Voice it in your placement area by ear. Heil used to have a mid and high LPAD for users to do this. The sound of the speaker is totally dependent on your room placement. We are taliking Jekyl and Hyde different here.
- Make sure you know the diaphragms you have. I encountered three different styles, all of which have different impedance and response characteristics. For all I know, there are thirty different ones out there.
As to your specific questions, The heil will be fine with 2nd order at 1500. It might even do 1st order, but I did not try this extensively. All crossover topologies have lobes and radiation patterns, there is no magic bullet to eliminate this. This design is much more complex than just the crossover pattern because of the Heil's inherent dipole radiation pattern. Good luck with it.
Dick |
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| Brad-Man |
Dick:
What are your thoughts about a design for utilizing the largest of the baffle-mounted heils (like from the PS series).
I happen to have 4 of them, along with a pair of PS5's and PS8's, and was thinking of making a center channel and maybe some some main speakers that would utilize 3 10" woofers for my home theatre room, and have my ML Quests and Velodyne ULD-18 with their own system just for music. |
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| dickmorgan22 |
I did not know there were any baffle mounted Heils, so I cannot advise you. I have seem some of the monopols AMT's others have done - these would be used just like any other tweeter I assume. What made the Heil I worked with so tricky was the dipole aspect. Are the baffle mounted ones still dipoles??
Dick |
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| Brad-Man |
Dick:
I think we have a bit of a communication problem and it is probably my fault.
I always was told the front panel of the speaker that the grill covers is the baffle, so I am talking about the monopole AMT's the largest of them actually - I have seen 2 sizes of the small AMT's. |
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| hndaaudio |
Dick,
Thanks for the interesting info.What do you think about a bipolar woofer setup on an open baffle ? I am new to open baffle designs,any suggested reading for designing such a system ?
My heils are from the 1D model,the diaphrams look silver.Do you know what the impedance is ?
ESS used to make baffle mounted monopole heils for the smaller models.I have not heard all of them,but what I did hear sounded terrible.I would stick with the large heils. |
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| planet10 |
| quote: | Originally posted by hndaaudio
.What do you think about a bipolar woofer setup on an open baffle ? |
It is not possible to make a bipole OB... an OB is inherently a dipole.
dave |
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| dickmorgan22 |
| quote: | Originally posted by Brad-Man
Dick:
I think we have a bit of a communication problem and it is probably my fault.
I always was told the front panel of the speaker that the grill covers is the baffle, so I am talking about the monopole AMT's the largest of them actually - I have seen 2 sizes of the small AMT's. |
I agree with your definition of the baffle. There is no reason one could not take a large heil and baffle mount it with an enclosure behind to swallow the back wave. One of my collaborators suggested just such a strategy. With a good box design, it would work. A monopole version of the heil would be one that has such a rear enclosure already installed, like standard tweeters do. In any event, I'm not a Heil guru, simply a speaker designer who tried a dipole Heil, and got my butt kicked. Conceptually though, a monopole Heil would be the same as any other tweeter in terms of the overall design process. MUCH easier than the dipole version.
| quote: | Originally posted by hndaaudio
Dick,
Thanks for the interesting info.What do you think about a bipolar woofer setup on an open baffle ? I am new to open baffle designs,any suggested reading for designing such a system ?
My heils are from the 1D model,the diaphrams look silver.Do you know what the impedance is ?
ESS used to make baffle mounted monopole heils for the smaller models.I have not heard all of them,but what I did hear sounded terrible.I would stick with the large heils. |
Dave is right, anything with an open baffle is a dipole by definition. The reason this might be even TOUGHER to do is that the large Heil is, by any definition, a dipole.....BUT it behaves more like a bipole. This is because it has an effective 12" baffle due to the design, and the front and back waves never really coherently meet each other at the frequencies of interest creating the characteristic dipole radiation pattern. Its radiation pattern is much more bipole-like. It sprays treble against the back wall the same way a bipole does. A Bipole woofer setup allows the radiation pattern into the room to be much more even over a wider range. Setting up the woofers as dipoles would be fiendishly difficult to get right I think.
As for the diaphrams, I cannot advise you, but an ohm meter can. The three versions I had (two different ones in the tweeters from Fleabay, and a pair from SimplySpeakers) were different. The new ones available on line were not as good as ONE of the diaphragms the tweeters came with, but I needed a matched pair. The new ones had a couple of items of interest.
- The cheesecloth covering them needs to be removed. They vibrated at 300 Hz rather loudly when it was left on. It just peels off easily.
- There is a wicked response peak at 7100 Hz on axis. It softens off axis, but you would need to notch it out....its about 6 dB high. Its about 2 KHz wide.
The impedance on these is 4.5 ohms. One of the others was just over six, and the other was just over seven. You have to measure it. The good news is that all three were dead flat down to 800 Hz, where they dropped a few hundred milliohms. Sorry, but two of them were visually identical, and the other very similar, so I would not trust a visual description as a replacement for a measurement. As I said, I have no reason to believe that there are not MANY diferent diaphragm versions out there.
Dick |
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