Thatch_Ear said:
Wouln't that be more appropriately called a Full Range?
Pretty much what jac (from over on the Full Range Forum is doing right now. He has Coral Betas on the bottom.
An externally hosted image should be here but it was not working when we last tested it.
dave
Kinda,not really. The Eminence beta rolls of at 10K but goes down to around 40Hz. Most full range drivers start higher and go at least up to 15K or so. This will be more along the lines of the Hammer but using a TL, and an AMT intead of a Super Tweeter.
Frazier did something like this in a kind of back loaded mini Onkin encloser using an 8" driver I believe Utah made for him back in 62. Not too deep they were the 'Bookshelf" of the day. I bought a pair off a guy and played them like crazy till the cones started falling apart. The woofer ran free and there was a 6db high pass on the tweeter. Very efficient as will be the Beta 12LT and the AMT. Probably a SPL of 97 to 98db/w/m. I want something very tube friendly and want to build it for the Texas Shootout which means I have to get started soon.
David
Frazier did something like this in a kind of back loaded mini Onkin encloser using an 8" driver I believe Utah made for him back in 62. Not too deep they were the 'Bookshelf" of the day. I bought a pair off a guy and played them like crazy till the cones started falling apart. The woofer ran free and there was a 6db high pass on the tweeter. Very efficient as will be the Beta 12LT and the AMT. Probably a SPL of 97 to 98db/w/m. I want something very tube friendly and want to build it for the Texas Shootout which means I have to get started soon.
David
Thatch_Ear said:
A matter of semantics then -- I know what you are trying to say, but 8 octaves in my book is a FR -- just missing an octave at either end, pretty balanced FR IMO. My FR are stretching to reach 60-80 Hz and a lot of tweaking & fiddling has the Ts coming in at about 10k, and it is definitly classified as a FR. I figure if it covers 7 octaves and is fairly balanced beetween top & bottom it is a FR.
dave
AMT-1 design in Hobby-Hifi 5/2002
There is a similar design in the Aug./Sept. issue of the German magazine Hobby-Hifi.
It uses an AMT-1 with some triangular structure behind it to deal with the backwards emmission of this dipole. Frequency response, decay time and disto plots of the AMT-1 are given (I guess without the case). The latter two are very good while frequency response has a strong directionality, showing severe high range loss at 30° horizontally or 10° vertically. Measurements of the whole speaker do not look much different.
Three special OEM Excel 17 cm woofers are used in separate bass reflex enclosures, two of which are allowed to operate up to 5 kHz and then rolled of at 6db/oct. The AMT is rolled of at 1.5 kHz, again with a first order filter. This broad overlap is supposed to result in a very "time-correct" behavior.
The Excel woofers, which have varnished magnesium membranes, have exceptionally low decay times and disto and are very flat out to 4 kHz when measured separately. There is a resonance at 4.5 kHz which is flattened within the XO.
In the completed system, there are some narrow dips up to 5 dB in frequency response, which must be due to the fact that three speakers are operative simultaneously. But they claim that this does not matter at all in a typical living room environment where room reflections have a larger effect. On the contrary, they claim that this speaker sounded extremely musical no matter where one was sitting.
Eric
There is a similar design in the Aug./Sept. issue of the German magazine Hobby-Hifi.
It uses an AMT-1 with some triangular structure behind it to deal with the backwards emmission of this dipole. Frequency response, decay time and disto plots of the AMT-1 are given (I guess without the case). The latter two are very good while frequency response has a strong directionality, showing severe high range loss at 30° horizontally or 10° vertically. Measurements of the whole speaker do not look much different.
Three special OEM Excel 17 cm woofers are used in separate bass reflex enclosures, two of which are allowed to operate up to 5 kHz and then rolled of at 6db/oct. The AMT is rolled of at 1.5 kHz, again with a first order filter. This broad overlap is supposed to result in a very "time-correct" behavior.
The Excel woofers, which have varnished magnesium membranes, have exceptionally low decay times and disto and are very flat out to 4 kHz when measured separately. There is a resonance at 4.5 kHz which is flattened within the XO.
In the completed system, there are some narrow dips up to 5 dB in frequency response, which must be due to the fact that three speakers are operative simultaneously. But they claim that this does not matter at all in a typical living room environment where room reflections have a larger effect. On the contrary, they claim that this speaker sounded extremely musical no matter where one was sitting.
Eric
Dave,
I know that it is considered to be a full range by many, but compared to a Lowther it's higher roll off at 10K just makes it hard for me to toss into the same catagory. But there ya go, a matter of semantics.
Kind of like like a single axis triax or a duplex. Full range, one basket but 2 motors. So is a 604 a single full range driver? Yes, but not really.
One of the reasons I like terms like mid range instead of dynamics or would call the Beta 12 LT a wide range instead of a full range.
It certainly can be used as a full range if you don't want to hear the complete range of frequencies in a recording. But since to be able to listen to the complete range you have to add a high frequency driver can it really be a full range? Conondrum.
So anyway I am soon starting construction on a 2 way using Heil AMTs and an Eminence 12" Conondrum in a TL.
Capslock, can you give me a bit more info on the triagular structure behind the AMT? Being able to build behind the AMT could be a great help with fitting the TL pipe into a cabinet.
David
I know that it is considered to be a full range by many, but compared to a Lowther it's higher roll off at 10K just makes it hard for me to toss into the same catagory. But there ya go, a matter of semantics.
Kind of like like a single axis triax or a duplex. Full range, one basket but 2 motors. So is a 604 a single full range driver? Yes, but not really.
One of the reasons I like terms like mid range instead of dynamics or would call the Beta 12 LT a wide range instead of a full range.
It certainly can be used as a full range if you don't want to hear the complete range of frequencies in a recording. But since to be able to listen to the complete range you have to add a high frequency driver can it really be a full range? Conondrum.
So anyway I am soon starting construction on a 2 way using Heil AMTs and an Eminence 12" Conondrum in a TL.
Capslock, can you give me a bit more info on the triagular structure behind the AMT? Being able to build behind the AMT could be a great help with fitting the TL pipe into a cabinet.
David
Elac and Eton AMTs?
Anybody have any experience with the Eton and Elac AMTs?
The Eton ER4 dipole AMT is about half the price of the AMT-1 by ESS, and it does not seem to be the AMT-2 (which is a monopole) with just another baffle. Distortion and pulse behavior seem to be on par with the AMT-1 from what I could gather from articles in speaker building magazines. I wonder how they achieve a homogeneous magnetic field with the hole thing being less than 10 mm deep and hence much smaller than the magnets of the AMT-1.
As for the Elac JET, I have seen some nice review of finished speakers in hifi magazines, but I don't think it is available for diy.
Eric
Anybody have any experience with the Eton and Elac AMTs?
The Eton ER4 dipole AMT is about half the price of the AMT-1 by ESS, and it does not seem to be the AMT-2 (which is a monopole) with just another baffle. Distortion and pulse behavior seem to be on par with the AMT-1 from what I could gather from articles in speaker building magazines. I wonder how they achieve a homogeneous magnetic field with the hole thing being less than 10 mm deep and hence much smaller than the magnets of the AMT-1.
As for the Elac JET, I have seen some nice review of finished speakers in hifi magazines, but I don't think it is available for diy.
Eric
hello Promitheus,
On the ESS speakers: if memory serves me correctly I think ESS had a AMT tweeter and a midrange tweeter unit.
I heard their speakers on several occasions both in the mid-eighties and later on.I must say I was impressed with their clarity and razor sharp speed in the most sensitive midband.
They had (as a complete system) two problems to my ears :
1/ they were rather directive ,seating was important ( this may be partly due to x-over design )
2/the woofer never seemed to be able to cope with the sheer transient attack over midrange-tweeter unit.
Other than than that they were amazing speakers which were very easy to drive even to ear shattering levels.
Even now I would go for them without much further thought.
Converting dollars to Euro : 120 USD cannot possibly turn into 500+Euro even allowing for shipping and import taxes.Sorry but something just does not compute correctly here.
Why not buy them directly from the US ?
3/The only European company for DIY speakers I know of using ribbons is German based Visaton although it's just a tweeter I can think of putting it to good use in a D'Appolito configuration for example.
Hope this was useful.
On the ESS speakers: if memory serves me correctly I think ESS had a AMT tweeter and a midrange tweeter unit.
I heard their speakers on several occasions both in the mid-eighties and later on.I must say I was impressed with their clarity and razor sharp speed in the most sensitive midband.
They had (as a complete system) two problems to my ears :
1/ they were rather directive ,seating was important ( this may be partly due to x-over design )
2/the woofer never seemed to be able to cope with the sheer transient attack over midrange-tweeter unit.
Other than than that they were amazing speakers which were very easy to drive even to ear shattering levels.
Even now I would go for them without much further thought.
Converting dollars to Euro : 120 USD cannot possibly turn into 500+Euro even allowing for shipping and import taxes.Sorry but something just does not compute correctly here.
Why not buy them directly from the US ?
3/The only European company for DIY speakers I know of using ribbons is German based Visaton although it's just a tweeter I can think of putting it to good use in a D'Appolito configuration for example.
Hope this was useful.
I have compared the AMT-1 to the Raven R2 tweeter, and also to the DECCA/Kelley DK30 and the Jordanow HRA531.
The Raven sounds more sophisticated than the AMT, but it can alos sound rather thin. That's meanly due to the fact that the Raven has got a rising output from 5 towards 30 kHz (like many ribbons do) The AMT on the other hand has got a bump between 3 and 10 kHz and has got an almost 4 dB lower output at 20kHz. (the DK30 on the other hand is completely flat within 0.75 dB!! from 3kHz to 30 kHz, can't measure any higher but it still goes on after that) You really should have to compensate for this, it helps a lot for the top-end defenition of the tweeter. After compensation it sounds almost as good as the Raven but with more "balls". Compensate the Raven for its output rize and it will be sounding "fatter"as well. However I still would not recommend the Raven to be used any lower as 3, better even 4kHz, not that it isn't capable of going any lower but it will become to thin again. Also forget about 6dB/oct filtering with them, they really don't like that, they can easily move out of their linear filed in this way. Steeper filter get a lot more detail out of them. Wouldn't use the AMT either with 6dB at 1,5 kHz or something. Never have understood the choice of ESS to combine them with a 10" woofer.
Problem with both drivers (as with almost any ribbon) is to find a suitable midrange wich can come up with the speed of these units. That's the reason I still have a love/hate relationship with ribbons. It about a hundred times easier to combine a midspeaker with a relativly slower dome tweeter, but I still haven't heard (have had Focal, Scan Speak, dynaudio, seas, Thiel, and several others) one yet that can come up with the detail and micro information of a good ribbon. Choosing for a ribbon means that that's the startpoint of your design, choose the other drivers to match them, otherwise you're risking a great dissapointment.
The Raven sounds more sophisticated than the AMT, but it can alos sound rather thin. That's meanly due to the fact that the Raven has got a rising output from 5 towards 30 kHz (like many ribbons do) The AMT on the other hand has got a bump between 3 and 10 kHz and has got an almost 4 dB lower output at 20kHz. (the DK30 on the other hand is completely flat within 0.75 dB!! from 3kHz to 30 kHz, can't measure any higher but it still goes on after that) You really should have to compensate for this, it helps a lot for the top-end defenition of the tweeter. After compensation it sounds almost as good as the Raven but with more "balls". Compensate the Raven for its output rize and it will be sounding "fatter"as well. However I still would not recommend the Raven to be used any lower as 3, better even 4kHz, not that it isn't capable of going any lower but it will become to thin again. Also forget about 6dB/oct filtering with them, they really don't like that, they can easily move out of their linear filed in this way. Steeper filter get a lot more detail out of them. Wouldn't use the AMT either with 6dB at 1,5 kHz or something. Never have understood the choice of ESS to combine them with a 10" woofer.
Problem with both drivers (as with almost any ribbon) is to find a suitable midrange wich can come up with the speed of these units. That's the reason I still have a love/hate relationship with ribbons. It about a hundred times easier to combine a midspeaker with a relativly slower dome tweeter, but I still haven't heard (have had Focal, Scan Speak, dynaudio, seas, Thiel, and several others) one yet that can come up with the detail and micro information of a good ribbon. Choosing for a ribbon means that that's the startpoint of your design, choose the other drivers to match them, otherwise you're risking a great dissapointment.
Well it´s a long time since I started this thread. I have finished my speakers by now.
I used 2 8 inch HDS205 woofers from peerless.
They sound great.
I am still fixing the crossover because I had a few problems.
The woofers had a 3-4 dB Bumb between 800-3000 Hz so I had to use a parallel L-C-R circuit to flatten the bump. I got a lot more bass. The mids where so loud before that I could here much bass.
At the moment I am concerned with the tweeters. I use them above 2200 Hz with a second order filter. The crossover I found for them has a cap that somehow corrects the output of the Tweeter but I am not sure if it is right.
Does anybody have info on the ESS tweeter. I mean Output to Frequency chart.
I used 2 8 inch HDS205 woofers from peerless.
They sound great.
I am still fixing the crossover because I had a few problems.
The woofers had a 3-4 dB Bumb between 800-3000 Hz so I had to use a parallel L-C-R circuit to flatten the bump. I got a lot more bass. The mids where so loud before that I could here much bass.
At the moment I am concerned with the tweeters. I use them above 2200 Hz with a second order filter. The crossover I found for them has a cap that somehow corrects the output of the Tweeter but I am not sure if it is right.
Does anybody have info on the ESS tweeter. I mean Output to Frequency chart.
Hi Promitheus,
You know where I got this graph from
There are always some differences between the measurements of Klang&Ton and HobbyHifi, but i think they give a very good indication of what the units do. (usually the T/S parameters differ, but the measurement-graphs are pretty much the same).
To calculate the filter you should measure the output of the unit(s) yourself (to get the best out of the units).
I use those graphs for selection of units, but measure it myself when I have it.
Grtz, Joris
You know where I got this graph from
There are always some differences between the measurements of Klang&Ton and HobbyHifi, but i think they give a very good indication of what the units do. (usually the T/S parameters differ, but the measurement-graphs are pretty much the same).
To calculate the filter you should measure the output of the unit(s) yourself (to get the best out of the units).
I use those graphs for selection of units, but measure it myself when I have it.
Grtz, Joris
ESS Air Motion Transformers
This is the 1st time I've ever posted to Anything(!), so please forgive any protocol errors. In 1973 I purchased a set of Heil AMT 1's after much research and listening. The comments so far are pretty accurate, but there are some serious discrepancies. Yes, the bass wasn't much. But the AMT's were outstanding! They are NOT ribbon or ribbon-like tweeters. In actuality, the convoluted diaphram acted more like 2 groups of bellows acting in seies, but in opposite directions. Hence, a dipole. Mine crossed over at 700hz. And they were seamless and pretty linear all the way past 20khz. Remember, every crossover point is an adventure in phase distortion. Also, the efficiency was 93db/w/meter in the INSTALLED driver........through a fat resister to better the woofer's 91db/w/m! In 1974 I purchased a second 10" woofer and desined a proper ducted port enclosure for them. 'Talk about night and day! Using a 3rd order crossover I acheived 28 - 22khz +- 4db. With small amps of the day clipping their little butts off you could over heat and melt the pleated diaphram. Just use a bigger/better amp. My next speaker project will feature multiple Heils or Ravens. I'm looking for a source for the old ElectroVoice 30W. No, it isn't a 30" woofer: It's only 28.25"!
This is the 1st time I've ever posted to Anything(!), so please forgive any protocol errors. In 1973 I purchased a set of Heil AMT 1's after much research and listening. The comments so far are pretty accurate, but there are some serious discrepancies. Yes, the bass wasn't much. But the AMT's were outstanding! They are NOT ribbon or ribbon-like tweeters. In actuality, the convoluted diaphram acted more like 2 groups of bellows acting in seies, but in opposite directions. Hence, a dipole. Mine crossed over at 700hz. And they were seamless and pretty linear all the way past 20khz. Remember, every crossover point is an adventure in phase distortion. Also, the efficiency was 93db/w/meter in the INSTALLED driver........through a fat resister to better the woofer's 91db/w/m! In 1974 I purchased a second 10" woofer and desined a proper ducted port enclosure for them. 'Talk about night and day! Using a 3rd order crossover I acheived 28 - 22khz +- 4db. With small amps of the day clipping their little butts off you could over heat and melt the pleated diaphram. Just use a bigger/better amp. My next speaker project will feature multiple Heils or Ravens. I'm looking for a source for the old ElectroVoice 30W. No, it isn't a 30" woofer: It's only 28.25"!
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