| To ESL or to Ribbon? - Click HERE for Original Thread |
| PhaseLockLoopy |
..that be the qweschun.
I did search the forums (hoping an admin doesnt delete his account :xeye: )
Does N E 1 know of a review that pitches ESL's against Ribbon planars?
If so I would appreciate a pointer
thx :Popworm: |
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| moray james |
| why don't you listen to some Maggies listen to some Eminent Tech's listen to some Quads to some ML's to some Inner Sound (Roger Sanders). Decide what you like for yourself. If you don't know what you like or want then the best solution is to do some listening and you will. |
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| el`Ol |
| Two important differences are that an ESL is easier to build, and the magnets you need for a planar magnetic are expensive. |
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| Calvin |
Hi,
there“s another big difference!! Sound!
The resolution, detail, precision and naturality of a good ESL is unrivaled (if the ESL is built properly, which is unluckily more than often not the case). I disagree with el ol. about the ease of building...a ESL looks simple but to get outstanding results the effort literally explodes! Ribbons are the try to get the advantages of an ESL out of a dynamic drive system. Of course....this failed. :dodgy:
It“s quite similar to the story of high output-MC-pickups compared to MM- and true MC-pickups. While true MCs need more effort with regard to amplification, they won“t be beaten in their overall sonic qualities.
jauu
Calvin |
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| PhaseLockLoopy |
I'm interested in building my own planars -- but have not decided on which direction.
Do I opt for the simplicity of ribbon - but as someone pointed out - huge magnetic expense
Or the complexity of ESL and the refined design aspects to think about to get it right - but with comparitively less expense.
I was hoping to find a hi-fi review that pitched ESL's up against Ribbon to see the varying differences on paper. |
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| ABJensen |
Elektrotats are too wide 20 cm :whazzat: .Planars (my diy) is 2 cm wide
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| Calvin |
Hi,,
Yeah, great stuff... You defy physics with a 2cm wide ribbon! :xeye:
Size matters! This holds true even for ribbons.
btw. I can“t see that the speaker is 2cm in width. There“s a baffle of considerably more width. A ESL doesnt need a baffle at all, just a thin frame to hold it. And more active diaphragm area and less baffle is always better than the other way round.
Besides: compared to the weight of an ESL-membrane, coated with a sub-µm coating a ribbon is heavy like a tank (small ESL: 1.500cm² -->less than 10mg, large ESL: 6.000cm² --> less than 40mg, typical 25mm dome tweeter: 5cm² --> around 250mg). This membrane is driven by an inherently linear drive system, whereas the ribbon features a nonlinear magnetic circuit. So distortion in a ESL is magnitudes lower.
jauu
Calvin |
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| Calvin |
Hi,
Yes, You“re right and I fully agree with Yoor last posting.
The pic shows an example of a flat panel where no measurements are taken against the extrem narrow dispersion, like segmenting a flat panel, or curving the panel.
In my eyes this is a example for one of those rather unproperly built devices. :apathic:
I know that it is the design philosophy of some designers, but to my opinion such a flat panel is of no sonic advantage. Instead are there severe penalties to pay, as for eg. an extrem small sweet spot which renders the system rather impractical for everyday usage.
jauu
Calvin |
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| moray james |
PLL has posted twice here and before we go farther into which is better I think that we should consider PLL's position. He is looking for a hi-fi review to discribe the difference between the two methods of design. I don't know how many hi-fi reviews PLL has read but most don't really tell you much of anything simply because the writter has not got a clue.
PLL does not discriminate between true ribbon designs and isodynamic designs (ie. Magnepan) nor does he seem to be considering fullrange Vs hybrid designs. Perhaps PLL needs to do an in depth study of what has been on the market and what is on the market and then ask some why type questions. A long time ago a guy by the name of Stan Kelly had a friend send him a small ribbon tweeter to evaluate. When Stan lifted the top off the small box to open it the vacuum created ripped the ribbon right out of the gap and Stan put the ribbon in the box onto the shelf. Some time later Stan went back to have a look at that ribbon and went on to design the London Decca Ribbon. Across the water a fellow by the name of Jim built a sturdy yet inexpensive ESL panel with a positive charge on the diaphragm (which will most often repell normally neg charged air particles) and did not even put a dust cover on his design. That designer bragged that he had never had a single field failure (panel) and to this day I have not seen one either. I think that Jim Strickland's Acoustat is the most robust and long lived esl panel the industry has known. PJ Walker's two esl designs are still today considered by many to be industry standards for more than thirty years. What lasts and what works and why are important things to know and to consider. Has PLL ever heard of a Hill Plasmatronic loudspeaker? Google has a patent search option if you click "more" the "even more". You can search the US patent office and find all kinds of interesting information on many famous designs for free, text as well as drawings. If this all seems like too much effort then just consider the alternate of figuring it all out on your own. I think a kit or the purchase of some used loudspeakers on which to experiment and modify would be the best and least expensive place to start such a journey. I can pretty much assure you that you are not going to find any revelations or overlooked gems in any hi-fi reviews those guys for the most part don't know and they don't care. Questions are good but you will not find any answers in the raggs. PS I did not forget Apogee I just like my bank cards the way they are magnetized and working. |
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| a.wayne |
| quote: | Originally posted by Calvin
Hi,,
Yeah, great stuff... You defy physics with a 2cm wide ribbon! :xeye:
Size matters! This holds true even for ribbons.
btw. I can“t see that the speaker is 2cm in width. There“s a baffle of considerably more width. A ESL doesnt need a baffle at all, just a thin frame to hold it. And more active diaphragm area and less baffle is always better than the other way round.
Besides: compared to the weight of an ESL-membrane, coated with a sub-µm coating a ribbon is heavy like a tank (small ESL: 1.500cm² -->less than 10mg, large ESL: 6.000cm² --> less than 40mg, typical 25mm dome tweeter: 5cm² --> around 250mg). This membrane is driven by an inherently linear drive system, whereas the ribbon features a nonlinear magnetic circuit. So distortion in a ESL is magnitudes lower.
jauu
Calvin |
Hello ,
Are you describing a planer magnetic as being non-linear or a RIbbon as being non-linear?
Both speakers ( ESL /Ribbon) has it's pros and con and for the original poster i would suggest to build a hybrid RIbbon , the electrostatic's would be more complex for a novice and more expensive to build. The heart of an ESL is the power supply and a good PS and AT makes it more expensive than the ribbon...
Personally i prefer the sound of a Ribbon/dynamic hybrid over an ESL, ultimately i would do a RIbbon /ESL /Dynamic drive Speaker for the ultimate listening weapon. |
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| salas |
| quote: | Originally posted by a.wayne
Hello ,
Are you describing a planer magnetic as being non-linear or a RIbbon as being non-linear?
Both speakers ( ESL /Ribbon) has it's pros and con and for the original poster i would suggest to build a hybrid RIbbon , the electrostatic's would be more complex for a novice and more expensive to build. The heart of an ESL is the power supply and a good PS and AT makes it more expensive than the ribbon...
Personally i prefer the sound of a Ribbon/dynamic hybrid over an ESL, ultimately i would do a RIbbon /ESL /Dynamic drive Speaker for the ultimate listening weapon. |
The large benefit of ESL & Ribbon panels up to 3kHz is the absence of a box IMO. I would prefer a well chosen pro 15inch and a 10inch open back handing over to a RAAL ribbon. From low sens to high sens is another world all together. Plus no membrane jigs and transverse modes. Sorry for the OT. |
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| moray james |
A.Wayne hopefully I have attached a schematic that as you will see is simple and not expensive to make. With some basic mods this supply will work very well. This is what Jim Strickland used in the Acoustat. I have seen simple converter HT blocks that are the size of your thumb that you run off of a small wall wart for $10.00 that would probably work as well. The supply does not have to cost a lot. I would say that you will end up spending the bulk of your budget on the step up transformers though used deals are out there.
If my attachment does not connect you can see theis supply at this page. http://www.izzy-wizzy.com/audio/spkrif.html |
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| vitalstates |
Hi Phaselock
Sound advice from Moray....go out and listen if you can find dealers...I'll guess that in the sales environments you won't hear much difference between the two formats....but....the difference in being able to build will be much greater...
The parts for ESL are readily available and a kit build is very practical....check out ERaudio, for parts if not for a full kit. There is a precis of my review for HiFi World on my web site for an Eraudio build which explains just how easy it can be.
Ed |
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| PhaseLockLoopy |
Hi Chaps
Thanks for all your replies
The prob for me is that there are no dealers around where I live that carry that sort of calibre.
I would have to go into London and have salesmen try and get me in the posh room -- take my wallet and sequestrate my assets.
I'm an engineer like most of you here and I take Morays points seriously -- however, I'm looking to get a project started because I'd like to have a go at building my own planar.
The few snippits of information I glean from knowing the Quad 57 and 63's is that the former had what they called"ventian blind treble" polar response - which was solved on the annular electroded 63. I used to own stacked 57's driven by Quad 303's converted to mono-blocs ( my own work back in 1986)
The 63's are weak -- live cathedral organ music makes them arc out (not on my stacked 57's btw)
Having this prior knowledge on electrostats as a user - I was wondering how things were faring in the performance of ESL against Ribbons -- and I like to read the perspective of reviewers if the review is scientific and they contrast and compare between both types. If that doesn t exist -- - then well - I'll just crack on and start thinking about my design parameters.
I'd like to see Quad 989 or Martin Logans - pitched against the equivalent Maggie, for example.
Once made - I could then set about designing and building the mono-blocs to run them. And have a good hi-fi again instead of the ***** I have right now
If you have a look in image -- you'll see my old stacked set up - and YES ! the long haired schmuck is me.
;) |
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| moray james |
you can contact Stewart Penketh at this address http://user.tninet.se/~vhw129w/mt_a...ir_penketh.htm. Stewart is one of the best Quad rebuildere there is. His configuration for stacking Quad 63 panels is excellent. Not only does it bring the concentric ring section up to ear level it also rotated the panels 90 degrees from stock which has the benefit of placeing the long axis of the inner most section in the vertical position which provides more horizontal dispersion and a little less vertical. So the sweet spot is wider and you have less floor and ceiling bounce (a good thing). There is from Stewart's reports no lack of bass. In fact you get eight panels to Quads new veersion with only six. The 63 panel is a direct drop in to the current Quad line up. My guess is that if you liked your old 57 stacked Quads you will like these better. O course you can build up all new panels of your own design and runn them off of a Quad 63 interface. That way you get to roll your own.
The Dutch ESL club has a host of design projects to read some are very interesting. http://esl.hifi.nl/index.htm |
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| Calvin |
Hi,
the suggestion: "Go to a dealer" might help, maybe not.
The first problem simply is that there are just very few dealers who have Ribbons and ESLs on display.
The second is that You can count the good examples of both technologies with just by 3 or 4 fingers. I regard Quad (m p o) as vastly overestimated. They have had their merits, which in part result out of history, but nowadays a good ESL looks and plays on a very much higher level. I never liked this dull and undynamik sound which is a result of the serious technical flaws of this special concept (I“m prepared to take on some bashing for “slaughtering a holy cow“) :D To my taste a Maggie outperforms Quads easily. But a (tweaked) ML Prodigy knocks the Maggie off of their Feet in seconds.
Thirdly, very few dealers have the knowlege and interest to correctly handle this stuff. Therefore the chance of a badly executed audition far away from optimal is rather high.
@ a.wayne
| quote: | | Are you describing a planer magnetic as being non-linear or a RIbbon as being non-linear? |
It doesn“t matter, both types“s motor are non-linear, with planar magnetics its much worse though. |
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| ABJensen |
Hi Calvin
Isnt it true that the field in and elektrostat, only will be linear if there are no holes ind the stators :) |
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| PhaseLockLoopy |
| quote: | Originally posted by Calvin
Hi,
the suggestion: "Go to a dealer" might help, maybe not.
I regard Quad (m p o) as vastly overestimated. |
Dealers are too far away for me - -besides I'll end up with having to listen to the gibberish from some slimey sales person with a wallet radar.
I agree - being an ex Quad Electrostat guy -- quite right - they are not what one would expect for the money - for the money Quad are asking they should be "exceptional" , but they never quite make it.
They do put my KEF 104/2 reference and my Cambridge Audio R50's and my "Icebricks" (Isobariks) to shame in the midband - treble and lack of colouration.
Thanks to all that have given me some nice linkies to read -- quite a lot of those have given me some ideas.
I think I may very well go for my own home made electrostats - so expect me to be playing with Mylar PP film - foil and drinking the coating fluid :D
Time to dust off my Bruel & Kjaer and Ferrograph test equipment :smash: |
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| a.wayne |
| quote: | Originally posted by Calvin
Hi,
the suggestion: "Go to a dealer" might help, maybe not.
The first problem simply is that there are just very few dealers who have Ribbons and ESLs on display.
The second is that You can count the good examples of both technologies with just by 3 or 4 fingers. I regard Quad (m p o) as vastly overestimated. They have had their merits, which in part result out of history, but nowadays a good ESL looks and plays on a very much higher level. I never liked this dull and undynamik sound which is a result of the serious technical flaws of this special concept (I“m prepared to take on some bashing for “slaughtering a holy cow“) :D To my taste a Maggie outperforms Quads easily. But a (tweaked) ML Prodigy knocks the Maggie off of their Feet in seconds.
Thirdly, very few dealers have the knowlege and interest to correctly handle this stuff. Therefore the chance of a badly executed audition far away from optimal is rather high.
@ a.wayne
It doesn“t matter, both types“s motor are non-linear, with planar magnetics its much worse though. |
I would have to dis-agree that the mag field on a true ribbon is non-linear when excursion is in the field , anyway yes it can be non linear if not designed correctly or used in an improper way , but it is ten times better than the acoustic phase issues of ESl's with a stator in front and back of it's diaphragm. There is so much smearing from an electrostatic ( compared to a ribbon , with ESL's i tend to favor open stators ) due to it's configuration , recording detail would have to be of low importance to live with that . ESL's do have an advantage in Speed ( very audible) but the smearing and gigantic big mouth sound all the time leave me cold ( my subjective opinion of course) with lack of detail and poor imaging it does a poor job of recreating time and space. The sound is open ( planers or big panel speakers do this well ) and READ not flaming anyone who likes it , just giving my objective and subjective opinion.
Calvin,
I do agree on the quad statement , do not agree on maggies ( poor ribbon speaker , good tweeter ) and do agree that you would only be able to find a handful of Commercially available ESL and Ribbons that are acceptable. I have heard really fantastic versions of both with the strengths and weakness described previously...............
As to the cost of magnets for RIbbons , a few years a go i had a fantastic supplier for magnets i can check to see if he is still in business , if so his prices back then where very reasonable, 120 typically to build a 4 ft ribbon driver.................. |
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| APi |
Just wonder if anybody has ever build narrow (~1") ESL line source as tweeter only? More robust than ribbon.
Polar response is like ribbon and if long enough, SPL shouldn“t be that big issue >1kHz? Any comments? Experiences? |
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| a.wayne |
| quote: | Originally posted by ABJensen
Elektrotats are too wide 20 cm :whazzat: .Planars (my diy) is 2 cm wide
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Would love to see more details on your ribbon speaker , could you please post more pics...... |
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| Calvin |
Hi,
if something as “acoustic phase smear“, lack of detail or gigantic mouth occurs it aint been a proper ESL or proper positioning of the device!
I don“t really know what You are talking about anyway?
ESLs can be built extremely open and very flat...so there“s no room for “phase issues“ whereas the size of the magnets of a Ribbon can lead to early reflections ahem...phase smear.
Anyway both systems are capable of acoustic phase linearity superior to the classical speaker.
But being a “massless“ system the ESL outperforms Ribbons easily with regard to resolution of details. The high proportion of direct sound vers radiated sound leads to a extremely precise localisation even of the tinyest sonic events. But You have to carefully control what the planar radiates to the backside. Otherwise You get the too big soundstage quickly.
@AbJensen:
If You design the ESL properly, You will have a perfectly homogenous field in which the diaphragm can move. Finite element methods are very helpful to show whats going on and how to design the stator.
jauu
Calvin |
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| I_Forgot |
I don't know why but a lot of people are under the impression that you must spend a lot of money and devote massive engineering resources to designing and building an ESL. Finite element analysis and EM simulations make wonderful topics of conversation but are also completely unnecessary. Quad certainly didn't use either in designing the ESL57s or 63s.
Some seek nirvana in diaphragm coatings, others in bias supply topology. In most cases the obsessive attention to these minor quibbles has greatest impact in the mind of the obsessor.
If you understand and keep in mind the simple physics that determines the performance of an ESL you can make a great sounding speaker comparable to any commercial ESL but at much lower cost. For example, you simply can't get low frequency response from any practical sized ESL unless you're making headphones. The low frequency response limit is inversely proportional to the size of the speaker.
The coating is there to allow charge to be placed on the diaphragm. High resistance, low mass, and above all, adhesion to the diaphragm are characteristics that matter.
The bias supply simply supplies charge to the diaphragm. Any high voltage DC supply is fine, but safety is a concern so a very small HV supply should be used.
The stators exist to establish an electric field that will move the diaphragm. Any perforated conductive material can be used. The stators also usually provide some mechanical rigidity to the speaker.
Insulators can be any insulating material, but they too usually provide some mechanical rigidity. They should be kept thin to make a speaker that is easy to drive with common power amps.
The trickiest stuff is the adhesives that hold the tensioned diaphragm to the insulators and the transformers that drive the ESL. Neither of these are well kept secrets.
Low voltage toroidal power supply transformers that are often available as cheaply as $5 each can be used to drive the ESLs with results that match those of expensive, purpose-wound audio transformers.
Construction methods for ESLs can be found on numerous web sites and in books. I prefer simple methods with proven reliability over some of the complex schemes found at some web sites, but you're free to choose the methods that appeal to you. Just keep in mind that everything that costs more in either cash or effort should justify itself by improved performance. Even using the simple and inexpensive techniques and materials yields results that are very hard to improve upon.
I_F |
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| Calvin |
Hi,
there are probable millions of “great sounding“ speakers out there.
And indeed its not that tricky to built a great sounding ESL. But isn“t the aim here to built something which is way above average?
If so, You have to pay attention to the smallest Detail.
Maybe because God is in the details ;-)
Than its just not so simple math (never wondered why there are nearly no usable sim-progs out there usable for ESLs?), not any coating, not any stator, not any insulator and definitely not any size and dimension.
To be able to build SOTA ESLs means slightly more than simply to put 5 parts together. ;)
jauu
Calvin |
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| PhaseLockLoopy |
HI Calvin
I am asking myself the usual product design questions as I set out my design parameters. :scratch:
What size? - physical shape?
What materials choices do I have?
Quality of materials?
Basically, what ingredients do I make the cake from ?
Power handling?
What Impedence structure (both mechanical and electrical) can I expect?
How many elements? :magnet:
:wrench: What are the knowns?
:wrench: What can I mathematically work out or predict from experience?
:wrench: What facts will I have to discover as I go through my build journey?
:wrench: What are the unknowns at this stage?
What innovation (if any) could I introduce to my variants?
I'm getting excited again -- this is the reason I exist....Science :) |
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| a.wayne |
| quote: | Originally posted by Calvin
Hi,
if something as “acoustic phase smear“, lack of detail or gigantic mouth occurs it aint been a proper ESL or proper positioning of the device!
I don“t really know what You are talking about anyway?
ESLs can be built extremely open and very flat...so there“s no room for “phase issues“ whereas the size of the magnets of a Ribbon can lead to early reflections ahem...phase smear.
Anyway both systems are capable of acoustic phase linearity superior to the classical speaker.
But being a “massless“ system the ESL outperforms Ribbons easily with regard to resolution of details. The high proportion of direct sound vers radiated sound leads to a extremely precise localisation even of the tinyest sonic events. But You have to carefully control what the planar radiates to the backside. Otherwise You get the too big soundstage quickly.
@AbJensen:
If You design the ESL properly, You will have a perfectly homogenous field in which the diaphragm can move. Finite element methods are very helpful to show whats going on and how to design the stator.
jauu
Calvin |
Calvin ,
Thanks for the response , Acoustic phase smear , LOL ,..................
Yes the ribbon does suffer from these reflections , ( all speaker's to some degree ) far less so than a ESL. Now an ESL with a closed grid is the worst (logans for eg.) , open grid is much better .
Now all speakers do suffer from various strengths and weakness's , the combined totals is what leads to the end results .
Speaking objectively an ESL is not a mass less speaker ( there is no such animal, quite possible you are being tongue in cheek, here ) and relative, speaker to speaker, a pure ribbon is still very light and is driven enough through it's length for the extra mass relative to an ESL, is negated by it's positive.
A Pure Ribbon is much more open and it's less obscure radiating area gives it a big advantage over the right in front of the diaphragm grid plates that affect an ESL. Again this is what makes audio enticing to the hobbist and Anathema to a designer /manufacturer . Technically sound does not make it universally loved.
Calvin i would love to hear how to build an ESL that is open and free of it's grid , the best i have ever done had a wired open grid stator and measurements still showed it had too much reflection vs a pure ribbon element ., subjectively it was audible also............
One last tidbit , the purely resistive load of the Ribbon , with very little phase angle changes make for a much easier load to drive than the low impedance capacitor of an ESL , this goes along way in how it affects the sound of an audio amplifier..
Now not saying Ribbon is Better than an ESL , Objectively and subjectively to me i prefer RIbbons , Hybrid Ribbons...
A.Wayne |
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| PhaseLockLoopy |
| quote: | Originally posted by a.wayne
One last tidbit , the purely resistive load of the Ribbon , with very little phase angle changes make for a much easier load to drive than the low impedance capacitor of an ESL , this goes along way in how it affects the sound of an audio amplifier..
Now not saying Ribbon is Better than an ESL , Objectively and subjectively to me i prefer RIbbons , Hybrid Ribbons...
A.Wayne |
When I heard the Magneplanar 3.6 -- I was very impressed with the punch it was able to produce -- for fun I chose the Dark Side of the Moon by Pink Floyd to see how it coped with the heartbeat at the intro.
There are so many other planars I have not had the experience of like the Martin Logans. |
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| ABJensen |
| Buy a used magnepan swap the ferritmagnets too neo.And gain alot in sensivity and dymamiks. |
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| el`Ol |
| quote: | Originally posted by ABJensen
Buy a used magnepan swap the ferritmagnets too neo.And gain alot in sensivity and dymamiks. |
I guess the diaphragm weight is much more important than the magnet type. The Analysis magnetostats have ceramic magnets and are worlds more dynamic than maggies. BTW, does anyone have schematic diagrams how Apogee and Analysis magnetostats are built? |
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| ABJensen |
| quote: | Originally posted by a.wayne
Would love to see more details on your ribbon speaker , could you please post more pics...... |
No pics. sorry have glued the frontplate |
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| a.wayne |
| quote: | Originally posted by ABJensen
No pics. sorry have glued the frontplate |
OK,
So the speaker is planer , not ribbon ? |
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| ABJensen |
| quote: | Originally posted by a.wayne
OK,
So the speaker is planer , not ribbon ? |
Yes its a planar. Ribbons is way too easy too make .And too my ears it sound more relaxed. And paper gives a nice warm sound. |
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| moray james |
PLL you should take a look at the Superior Essex list of magnet wire a numberr of dual coat versions which have breakdown voltages over 12Kv http://www.superioressex.com/magnetwire.aspx?id=1390
The Dutch ESL groups have for the most part gravitated toward insulated wire stator construction as there are many benefits over perf metal. If you want to gow with perf metap I would suggest having someone like Russ Knotts at just ral music coat you panels to your size. That way you know that they will work and that they will all be the same. The average powdercoat shop does not have the experience to do this kind of coating and you only get one attempt per panel so it can be an expensive learning curve.
Go for the thinnest mylar C or Hostaphan RE you can find 2.5 - 3.5 micron. You might see if you can find low micron PEN Teonex Q72 film which is even stronger that the PET films (Milinex, Mylar and Hostaphan RE). Teonex is made by DuPont.
The standard Acoustat panel has an overall size of 9"x 46" and an active driven area of 6.75"x 43". Each diaphragm has a 1/2 inch wide peripherial non driven gap of diaphragm. I know that under the right conditions four such panels per channel can make astounding bass so I dont think that you would need to have more panel area than that. That's it for the moment. |
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| Calvin |
Hi,
@wayne
I admit I had some difficulties to understand your text! But I hope I got it all right that the answers will be ok ;-)
A ESL is of course not a “massless“ speaker , but its generally referred to as such, because its diaphragm mass doesn“t play a significant role in any respect -and in no formula- throughout the audio band. Mass related rolloff for examples lies way above 20kHz for typical materials like Mylar of less than 6micron thickness.
| quote: | | A Pure Ribbon is much more open and it's less obscure radiating area gives it a big advantage over the right in front of the diaphragm grid plates that affect an ESL. |
I don“t agree with that. You regard the grid as an obstacle with a negative effect. But that is rather not the case. It could instead be far more regarded as a flow resistance that introduces some kind of damping, which would otherwise be completely absent with all the negative side effects. Some Ribbons miss out any form of mechanical damping (accompanied with the always present danger of destroying the delicate thing)
I seriously doubt that You could measure any possible influence at all...if so, I“d like to know how You possibly have done it! The dimensions (hole sizes, wire distances et al) are so small that You couldn“t proof what You claim with typical microphone capsules and measurement setups.
Audible comparisons are in this case imho useless because they underly greatly the personal taste, require enormous listening experience together with profound technical knowledge of both principles, a usually lacking number of test specimen, and the sound of different specimen of the same principle varies vastly even with minor design differences.
It makes for example remarkably large sonic differences what coating is applied to an ESL-membrane. How will You be able than to tell of what influence a stator-construction is? Spacer distance and thickness, panel size....and there are many more variables that affect the sound of a ESL.
What makes You sure that You simply did listen to a rather badly designed panel or a different sonic effect?
I appreciate You saying that Your impression is subjective....so is mine ;) I heard Maggies, I heard Analysis. And while I admit that I liked especially the Analsysis very much and she outperformed some of the better known ESLs it was no match to a tweaked ML, a Capaciti or my own Panels.
You are completely right with regard to the ease or difficulty of drive needs. But a amplifier just needs to be designed apropiately to drive an ESL without any signs of stress. There are not many on the market though....but than again.....isn“t this here not all about good stuff?? ;)
The Kronzillas are prime examples of an fine tubeamp that doesn“t care what is connected to it and there are some decent class-d amps around that have equally no problem of driving the ESLs.
@loopy
If I count the words I“ve written in forums about ESLs over the years, I“d been better off if I“d written a book instead :D
Well there are imo no good short answers as long as there“s no sharp image of what You want to achieve and the amount of effort You“re willing to put in such a project.
I“d recommend to read copies of Mr. Sanders“s, Peter Baxandall“s and Ron Wagner“s texts to get a basic understanding of the functioning, design and used materials of ESLs. Searching this forum will reveal lots of “secrets“ too.
Just one recommendation: As a first project do Yourself a favour and don“t start with a FR-ESL!
jauu
Calvin |
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| a.wayne |
| quote: | Originally posted by moray james
PLL you should take a look at the Superior Essex list of magnet wire a numberr of dual coat versions which have breakdown voltages over 12Kv http://www.superioressex.com/magnetwire.aspx?id=1390
The Dutch ESL groups have for the most part gravitated toward insulated wire stator construction as there are many benefits over perf metal. . |
| quote: | Originally posted by Calvin
Hi,
@wayne
I admit I had some difficulties to understand your text! But I hope I got it all right that the answers will be ok ;-)
I don“t agree with that. You regard the grid as an obstacle with a negative effect. But that is rather not the case. It could instead be far more regarded as a flow resistance that introduces some kind of damping, which would otherwise be completely absent with all the negative side effects. Some Ribbons miss out any form of mechanical damping (accompanied with the always present danger of destroying the delicate thing)
I seriously doubt that You could measure any possible influence at all...if so, I“d like to know how You possibly have done it! The dimensions (hole sizes, wire distances et al) are so small that You couldn“t proof what You claim with typical microphone capsules and measurement setups.
Audible comparisons are in this case imho useless because they underly greatly the personal taste, require enormous listening experience together with profound technical knowledge of both principles, a usually lacking number of test specimen, and the sound of different specimen of the same principle varies vastly even with minor design differences.
It makes for example remarkably large sonic differences what coating is applied to an ESL-membrane. How will You be able than to tell of what influence a stator-construction is? Spacer distance and thickness, panel size....and there are many more variables that affect the sound of a ESL.
What makes You sure that You simply did listen to a rather badly designed panel or a different sonic effect?
I appreciate You saying that Your impression is subjective....so is mine ;) I heard Maggies, I heard Analysis. And while I admit that I liked especially the Analsysis very much and she outperformed some of the better known ESLs it was no match to a tweaked ML, a Capaciti or my own Panels.
You are completely right with regard to the ease or difficulty of drive needs. But a amplifier just needs to be designed apropiately to drive an ESL without any signs of stress. There are not many on the market though....but than again.....isn“t this here not all about good stuff?? ;)
The Kronzillas are prime examples of an fine tubeamp that doesn“t care what is connected to it and there are some decent class-d amps around that have equally no problem of driving the ESLs.
@loopy
If I count the words I“ve written in forums about ESLs over the years, I“d been better off if I“d written a book instead :D
Well there are imo no good short answers as long as there“s no sharp image of what You want to achieve and the amount of effort You“re willing to put in such a project.
I“d recommend to read copies of Mr. Sanders“s, Peter Baxandall“s and Ron Wagner“s texts to get a basic understanding of the functioning, design and used materials of ESLs. Searching this forum will reveal lots of “secrets“ too.
Just one recommendation: As a first project do Yourself a favour and don“t start with a FR-ESL!
jauu
Calvin |
Calvin,
There is a reason why ultimate esl are made with open wired stators vs perf metal ( as also expressed by james moray post) and yes the difference and it's influence can be measured. Your comments on ribbon drivers tend to discuss them as
full bandwidth drivers , that they are not and i would never use a ribbon driver below 250 Hz. as there are better choice's for this .
Anyway grab your perf/metal esl and measure its frequency response vs an open grid wired stator esl of the same dimn.
you will see there are far less reflections. Ironic that as you point out and technically I'm in agreement with you about planer magnetic drivers being non linear , yet i have never heard any ESl of any dimn out perform an Apogee in the bass , the power from the planer is fantastic and is the best part of that speaker , of course takes a life time to get it right in the room , but when you do , fantastic.
As far as ESL's go i have listen to many , tested a few and A/B comparison too many to count, Soundlabs, Logans,( including the statement) Acoustat, Quads, single stacked , triple stacked, Bozak,
ohh gosh so many over the years most recently one called FInal, barely acceptable that one ....... |
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| moray james |
| A.Wayne: I agree with Calvin on this one and not just for ESL's but for Ribbons too. Bith ribbons as well as ESL's require additional resistive damping to controll the diaphragm as the local air load is not enough to do the job and the higher the diaphrgm mass the more so required. I you read about the Rall Tweeters you will see such statements. For ESL's I think that the optimum open area is around 30 - 35 % open stator to provide enough air load on the diaphragm. Most people shoot sor 40 - 50% open and I think that this is too high. I know that a chap by the name of Dave Lang did some fine studdies and published them in speaker builder some years back and he was surprised to find that a perf metal plate of 30 - 35 % open was in fact more efficient than a aluminym screen stator with a much more open area with wires every 1/16 of an inch in each direction. Dave's expectation had been the reverse so he was very surprised. |
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| a.wayne |
Moray,
I do use damping on My ribbon drivers and more so below 800 hz. on a ESL an open stator is far less efficient than a perf metal stator, this is the reason for perf stator, it is for more efficiency. If someone thought otherwise he missed ESL 101. :)
For clarity , if you are talking for bass then i would agree and use a perf stator , but for mid/high frequencies an open stator is superior .
Now on a 30 -40 % open stator , where you are going for better damping and efficiency , what happens to the speaker in relation to phase angle with frequencies above 8K ?
AW |
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| moray james |
| the aluminum screen wire had open areas that were 1/16" x 1/16" and the wire was the standard that we all see in bug screen. The perf metal had much larger size holes but a lot less open area overall. That was where the surprise came in. The bug screen had much better coverage as well as a far more open area but the perf metal worked better. I think that what was happening was that the reduced open area of the perf metal provided a better air impedance match between the diaphragm and the air in the room and that may be why the efficiency was better. |
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| a.wayne |
Ok,
I see, it would appear that he was using too thin a stator to generate a proper field, i would think, using something as thin as a bug screen ! |
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| I_Forgot |
See, this is what I am talking about. People think there hear a specific effect and then come up with all sorts of ideas about it, but no one tests the ideas so in the end, all that remains is some guy on a forum said this or that and people accept it as truth when the reality is it has never been tested.
There is no such thing as the stator being too thin to produce the required electric field. It is simple physics. 1 atom thick metal would be sufficient, but not desirable from a mechanical standpoint. Quad ESL63s for example use what is essentially perforated PCB material with a layer of copper that is certainly much thinner than the wire used in window screens.
If you want make meaningful speculation on why there may have been a difference between the speakers you have to know if all other aspects of the speakers were identical and the only difference was the construction of the stators. This seems unlikely due to the different mechanical construction techniques that would be required to support a flexible wire screen and relatively rigid perforated sheet metal.
In the end, ESL construction is dictated by aesthetic and practical considerations such as size of room and space available for the speakers, and by mechanical requirements- you have to keep a large surface area device rigid and that requires certain construction practices.
ESLs are NOT as complex as people keep trying to make them out to be. I say this from experience, not from speculation about quantum mechanical effects and other mumbo-jumbo that creeps into anything having to do with quality audio. There is no ideal formula for diaphragm coatings and no one best circuit for bias supply. There is only what works and what doesn't, what is safe and what isn't, what is reliable and what isn't. Audible differences between materials are at most minor and most of the time probably exist in the mind of the listener more than in their ears.
I_F |
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| moray james |
| I have built a good number of panels using #28 and mostly #30 gage double build magnet wire and tefzel wire wrap wire on 1/2 inch cube louvre as a base (just as in Acoustat's) with 15 -24 wires per inch. The 15 wire per inch had the same open area as the stock Acoustat's (which used 24 gage wire with very thick PVC dielectric) at 5-6 wires per inch. The 24 wire per inch versions are the best ones. I would guess their open area around 35% perhaps a little less. I use a 24 thread per inch threaded rod to align the wires so they are very uniform. It is fast and easy to wind a stator this way. The adhesive bonding is the slow part as I don't like to use really toxic adhesives. Citrus based model cement glue works well but it is slow to harden up. But you only have to do this once. I have yet to try this method with proper application of dilute base coat then full strength PVA adhesive which is totally non toxic but I do plan to give it a go sooner or later. |
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| MJ Dijkstra |
In many cases, the quality of design is more important than the fundamental technique (ribbon/esl or hybrid/fullrange).
Making general statements about which is the best doesn't work most of the time. |
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| Toaster |
| A mild rebuke PhaseLockLoopy- as someone who worked as a salesman in both audio and music shops for 20 years, I don't appreciate the 'slimy salesman' comment earlier at all. In all my time in retail I attempted to sell based on the needs of the customer, and virtually all my colleagues did too. Yes, it's business and you need to make a sale, but my philosophy always was to treat people properly to create a good relationship with the customer, that way the customer gets what they want and you get more business. It's fortunate for any dealer selling ribbons and electrostats that your prejudice means you are unlikely to trouble them by wasting a bunch of their time listening to equipment for research purposes that you'd have no intention of buying! I would also point out that I won't be the only member of the forum who has worked in retail! Salespeople may be convenient stereotypes to act as hate figures for some people, but the folks I worked with over the years- despite the odd cynic- were people who cared about audio, music and their customers, despite all too common experiences of time-wasting or abuse. |
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| ABJensen |
| Yes and if you where onlooky you got one of those know it all diyer in the shop :hot: |
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| Calvin |
Hi,
| quote: | | Anyway grab your perf/metal esl and measure its frequency response vs an open grid wired stator esl of the same dimn. you will see there are far less reflections. |
Oh my gosh, I can“t see a thing! It must be some invisible alien mindray frying my brains! (just kiddin, forgive me, but I“m Calvin am I?) :clown: :D
Guess, I“m doing right that for 25 years and ought to know one thing or two by now about the differences between sheet metal and wire stators and haven“t had one measurement yet which gave a hint to any phase smear effect (and I“m not talking about cheap diy-measuring stuff here!).
But since you brought this topic, I ask You kindly to proove Your (repeated) claim and show us just one measurement showing this effect!
And no, to built a ultimate ESL is no question of perf metal or wire, but to know which one suits the application best. Sheet metal has advantages with smaller d/s spacings while wire is fine for larger d/s spacing. So I wouldn“t use sheet metal for a fullranger or bass, as I do for my hybrid-panels. Wire is probably the best and easiest to use for a bass-panel (the safety requirements alone for the needed voltage values rather rule out perf metal sheets!)
Wayne“s assumption is quite the opposite, but still I regard it as wrong. So I admit not to know ESL101 at all :D
If your aim is for example to reach highest dynamic capabilities and resolution a fully driven sheet metal panel outperforms a segmented wire stator. You can proove this in praxi as well as in theory!
A sheet metal stator usually needs far lower transformation-factors (~ factor 2) which eases the transformer design, reduces losses and allows for improved sonics simply through the superior qualities of the transformer-panel system. I find it for example rather peculiar that someone actually thinks that a transformation factor of >>200 can be of any good (see Quad).
So the ultimate ESL could only be the one that fits certain parameters and needs best and since those are variable, there is no such thing as the ultimate ESL or Ribbon or loudspeaker in general.
| quote: | | ESl of any dimn out perform an Apogee in the bass |
To perform on an comparable level the ESL had to be of considerable larger size. The reason for this is that ESLs can“t produce as much power per unit area as dynamic speakers and therefore a ESL always has to have larger diaphragm area.
That is -besides rising conceptual and constructional difficulties and other severe disadvantages- the reason why I stick to hybrid-ESLs assisted by dynamic bass drivers.
It“s my opinion that the ESL with the best overall performance is a hybrid.
jauu
Calvin |
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| el`Ol |
ABJensen,
have you thought about doing it like Stage Accompany an others? Would you lose too much diaphragm surface due to the front pole plates? |
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| ABJensen |
| quote: | Originally posted by el`Ol
ABJensen,
have you thought about doing it like Stage Accompany an others? Would you lose too much diaphragm surface due to the front pole plates? |
Yes I have.but the only reason I can see is it is easier too make.because you dont need return wire.The problem is you get more reflektions from the iron and more non-linear field . And now it is 93db one watt. Thats enough for me. |
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| fivestring |
| I`ve been following this thread with great interest. From my personal experience ESL`s sound hyperdetailed and dynamic in the midrange, but with very limited dynamic range in the high and low frequency portions of the spectrum. They seemingly offer more detail than exists in live music, without a proper timbre rendering of a complete instruments (or voice) sound. The most lifelike timbre I ever heard from an ESL was when I listened to one of the biggest Soundlab speakers. Most ESL`s I ever auditioned were thin sounding though. There is one particular thing that really bothers me with ESL`s and that is the sound of the foil, which is very specific. They are very sensitive to the quality of electricity and on a bad day they give a very syrupy, dead sound. Although all speakers (and systems) suffer from this to a degree, ESL`s are especially sensitive to this problem. Corrugated ribbons on the other hand, give too much artificial "sparkle" that I find downright annoying and "hifi-ish" in character. Although very airy and transparent, they have a sort of "greyish" (odd order distortions) character to their sound, which is not very close to the live sound. I do consider flat non-corrugated ribbons very interesting though and I believe that for a midrange usage they only need to be corrugated at their ends (suspension) in order to provide some practical movement of the foil. Planar magnetics are potentially very interesting, especially the likes of modified Maggies (Magnestand). I do like detailed sound, but only if it`s tonally correct. Don`t want to start a war, just my 5 cents. |
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| MJ Dijkstra |
Hi,
The thin sound is probably caused by improperly designed full range esls.
If bass lacks, you will hear details in the midrange you didn't notice before (hyperdetail). That's probably the reason you only liked the very big esls.
Some esls like quad are a bit shy in highs because of additional protective grills/foils. But it can be the other way round as well.
I can't understand the fluctuating performance unless humidity of air is a factor. |
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| LineArray |
| quote: | Originally posted by fivestring
I do consider flat non-corrugated ribbons very interesting
though and I believe that for a midrange usage they only need
to be corrugated at their ends (suspension) in order to provide
some practical movement of the foil. Planar magnetics are
potentially very interesting, especially the likes of modified
Maggies (Magnestand). I do like detailed sound, but only if it`s
tonally correct. Don`t want to start a war, just my 5 cents. |
I think it is all about controlled motion of an area of foil or film.
Whether driven by lorentz force or electrostatically does not
matter to our ears. Using electrostatic force it is maybe more
easy to apply that force to a larger area. Using lorentz force
this is more difficult and you have to introduce voice coil like
structures on the moving foil by glueing, printing or vaporizing.
In case of a magnetic transducer with large area the shape of
the magnetic field gets more complex, because you will need
more than one N-S pole and you cannot avoid to place magnets
in front or behind the diaphragm.
Thats why a "true" ribbbon tends to implement a line source.
This is the "natural" way of constuction, which is able to
keep the diaphragm free from disturbing magnet structures in
front or behind, thereby allowing dipole radiation
if you want.
But the normal way of doing this, using a long ribbon
fixed at its short ends and folded or rippled multiply along
the short side, leads to some disadvantages.
- the ribbon produces a bowing along the long side when moving,
with maximum excursion in the middle. This is commonly solved
by introducing some more fixing points along the ribbon, if its
a really long one.
- there is a long slot at both sides of the ribbon, it cannot
contact airtight to the magnet pieces. Both slots are bordered
by the diaphragm, which is thin and sharp.This causes noise and
distortion with higher excursions.
- because of the high excursion in the middle, the magnetic
gap has to be rather deep along the whole length of the
ribbon to obtain a homogenous field, even though you would
not need that depth of the gap along the whole length concerning
excursion only.The deep magnetric gap will cause protruding edges
in front and behind the ribbon, which spoils radiation pattern
and proper acoustic coupling with the surrounding air.
- it is impossible to adjust the diaphragm to a resonant frequency
high enough for practical efficiency unless using tension along
the ribbon - which in turn causes AGEING.
All of those problems can be solved by using a folding along the long
side of the "ribbon".
- The long sides can contact the pole pieces in an airtight manner.
- Excursion is - mutually - the same over the whole length of the ribbon.
Depth of the magnetic gap can be reduced, the diaphragm can be
mounted to change almost flat into the speakers cabinets baffle.
- Resonant frequency is tuned by appropriate folding (rippling)
concerning the mass of the diaphragm material used.
- The structure can be mounted into the frame without using tension,
which yields very good long term stability.
- Even this structure will bend when driven, but the bending mode will
improve the horizontal radiation angle, because it bends along the
short sides.
To be honest, by folding the long side, there arise some technical
problems. E.g. the electrical contacts at both ends have to be designed
not to disturb the bending motion or to introduce bending in unwanted
directions. But that can be done by proper design and experience.
IMO this kind of "ribbon" is in advantage over an electrostatic
device in at least three aspects:
- capability of large linear excursion
- far less diaphragm area needed, which leads to far less
problems with unwanted vibrational modes and beaming
- unobstructed area in front and behind the diaphragm
And by the way: This is exactly the way it sounds.
Regards
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| fivestring |
@LineArray,
I agree with your interesting observations. I never did understand how a classic corrugation could reinforce the ribbon structure in any way, without creating more problems than it was aiming to solve. Awhile back I was thinking of vertical corrugation too, but was wondering if the air load in front and back of the ribbon would put too much pressure on the foil and force it to expand under higher excursion, which in turn could cause a short circuit (I hope I understood what you said, the photos have really low resolution). All this may not be valid for short ribbons,but for taller ribbons I do have some reservation though. I already successfully modified some commercial (smaller) ribbons with flat foils, but I am using them only well above 6 khz, because I find them very undynamic sounding below this frequency. From a phone conversation I`ve had with Aleksander Radisavljevic (RAAL), he told me how corrugated ribbons totally loose their control under high power/excursion and move chaotically. I guess even a small blast of wind could make them wave like a flag. I am considering of building myself a taller (1 or 1.5m) ribbon and am thinking of making it totally flat. I am interested only in the range above 300 hz and I wonder how much excursion would be needed in that range with a planned 2 order crossover. The ribbon itself would be about 2 cm wide and with a length of some 1.5 m there is already 300 square cm of effective surface, which is more than a 8" woofer has. I planned only a single corrugation at both ends, perhaps with small mylar foil reinforcement in order to provide some excursion under higher power. I am not sure if there is any practical need for extreme ribbon excursion in the midband and above (Advanced Ribbon Technologies claims 1" peak to peak excursion for their ribbons). At this excursion levels, doppler distortion must rise to enormous levels and the sound is probably horrible.
Best regards |
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| Calvin |
Hi,
imho one of the biggest failure one can make is to think that a large membrane area is something negative. Of course is it easier to have a wide dispersion with smaller, less wide structures, but the little you gain here (if it is of any positive use is debatable anyway) is offset by condsiderable losses in the dynamics and distortion department.
While the distribution character is rather a parameter which affects the kind of usage of a speaker (every day and everywhere->wide dispersion, fixed to a certain position-->listening as a act of doing nothing else besides) and is more a matter of higher freqs. Dynamics and distortion on the other hand are are directly influencing the complete frequency range and so the sound experience. It s my impression that every speaker that has deficiancies here, sounds artficial and unreal. You only can optimise dynamics and distortion at the same time by enlarging membrane area, but not by increasing excursion capabilities.
With regard to this ESLs can reach very high dynamics (comparable to horn speaker, but with even increased low level resolution) with exceptional low distortion values (the majority of distortion depends more on the used audio tranny than the panel itself).
If there would be any problem with the stators beeing “obstacles“ within the soundpath one should see artifacts within the the distortion measurement, right? How comes then that the distortion values of a really good panel are much lower than any other principle especially at elevated SPLs?
jauu
Calvin |
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| LineArray |
| quote: | Originally posted by fivestring
@LineArray,
Awhile back I was thinking of vertical corrugation too,
but was wondering if the air load in front and back of the
ribbon would put too much pressure on the foil and force
it to expand under higher excursion, which in turn could
cause a short circuit
(I hope I understood what you said, the photos have really
low resolution). |
Hi fivestring, i think i understood the effect you feared.
Maybe unwanted expansion of folds when diaphragm is
loaded with over/underpressure at both sides respectively
could occur, when the folding is too deep and "edgy".
But that kind of folding is not desired anyway because the
compliance across the short side would be too high, giving
a fs which is too low. Such a folding would additionally increase
diaphragm mass to a higher extent, because more material is needed.
With the corrugation i used, this is really not an issue.
I tried to attach a better pic. The folding symply looks like
a miniature corrugated iron.
I thought of upsizing my tweeter before. To make it taller is no
problem. To make it wider (8mm wide now) is more tricky.
Using the same corrugation pattern, compliance will increase and
mass too. Which is your desired fs ? (100...200 Hz ?)
Maybe the corrugation has to be modified into flatter, maybe
at a certain point one has to think about a stiffer foil, i don't
know. But i feel probability is high, that one could make it wider
by changing nearly nothing.
I personally would not go to a completely flat diaphragm, because
i would fear uncontroled motion at the upper end of the frequency range
with a diaphragm 2cm wide. But i havent done it and maybe it is a way to go.
Would reinforcement of corrugated borders help at higher
frequencies, if the diaphragm is flat ? It seems rather complex,
but again maybe your idea is right.
I would like, if you kept me updated with your experimenting,
because someday i'd like to upsize my prototype and any
experience is valuable.
@calvin:
There seems to be a little misunderstanding. I don't think large
diaphragm area is negative as such. But please keep in mind, that the
area of my example tweeter is already much bigger compared to a dome
tweeter. It is a tweeter, not a fullrange ribbon.
Large radiating area is interesting, as long as the motion is kept
under control and there is no breakup.
The stators of an ESL can be kept rather thin and acoustically
"transparent" ore "pure resistive" that is true. With a magnetostatic
device this is more difficult, because even modern magnets need some
space for themselves and their fixation in space.
If we look at Quad ESL 63
- which to me is one of the most valid speaker designs -
the size of the radiating area shrinks with increasing frequency
As far as i know there are two reasons to do that:
- Avoiding uncontroled breakup of the radiating area at the upper end and
- Controling the radiation pattern.
A radiating area with diameter 100 x Wavelength is not really needed
or useful but has to be curved to obtain a useful radiation pattern.
Discussion depends on the aims of construction: Tweeter or Fullrange.
Best Regards
Oliver |
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| Calvin |
Hi,
the reduction in membrane area serves the linearization of the frequency response in first case. Curving a panel serves a similar purpose. Breakup can“t be avoided with both techniques, as can“t be with any speaker relying on membranes, plasma maybe the only exemption. But both techniques take care of the distribution pattern, which a non-segmented flat stator does not and which I don“t regard as a good or uptodate-design.
Though the idea behind the complex circuitry of the Quads is a brilliant theory, the concept has major basic flaws and there is nothing gained by the tremendous effort, that a much simpler electrical segmentation with resistors only, can“t do equally well. The Quads are a masterpiece to learn from how certain things should be done and other certain things should not be done. The rings belong to the things that should not be done, imho. :cool:
jauu
Calvin |
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| LineArray |
Hi,
calvin, can you point me to an ESL design, which has
all of the design features you prefer ?
Just some Links would be helpful.
Cheers Oliver |
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| fivestring |
Hi Oliver,
I guess the corrugation we talk about doesn`t have to be deep at all. One could make three corrugations at the centre of the foil and when you attach the ribbon to the frame, the foil will tend to straighten itself again, but the slight corrugation ribs will remain and ensure the stabilizing effect over it`s shape, during the motion. As for the mylar reinforced corrugations at both ends of the ribbon, I only wanted to ensure some elasticity of such "suspension" and to avoid ageing of the pure stretched flat ribbon, but then again I am not sure if this would be necessary at all, since planar magnetics don`t have any suspension either (just a foil stretched onto a frame) and are used down to the mid frequencies. I don`t know, perhaps I am completely wrong...
Best regards |
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| Calvin |
Hi,
@LineArray
:scratch: :scratch:
:wiz: :wiz:
Mine of course
http://www.diyaudio.com/forums/show...threadid=124282
:Pinoc:
Naaa, just kidding....or? ;)
Conceptually I think the ML Statement and even more the StatementII were very close to optimum. But both of rather impractical build size and price. Both with curved stators. In the DIY-segment I find the Capaciti very well made, which feature segmented planar stators.
Against many, I“m of the opinion that a Hybrid-ESL can be made with a seamlessly integrated bass. If done so You benefit from the superior qualities of the dynamic drivers in the bass region like compactness, ease of drive, higher linearity and lower distortion.
From the bass on upwards there“s nothing that imho comes close to a ESL. Linearity, distortion, resolution, naturalness are just a few points to name.
jauu
Calvin |
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| a.wayne |
| quote: | Originally posted by Calvin
Hi,
imho one of the biggest failure one can make is to think that a large membrane area is something negative. Of course is it easier to have a wide dispersion with smaller, less wide structures, but the little you gain here (if it is of any positive use is debatable anyway) is offset by condsiderable losses in the dynamics and distortion department.
While the distribution character is rather a parameter which affects the kind of usage of a speaker (every day and everywhere->wide dispersion, fixed to a certain position-->listening as a act of doing nothing else besides) and is more a matter of higher freqs. Dynamics and distortion on the other hand are are directly influencing the complete frequency range and so the sound experience. It s my impression that every speaker that has deficiancies here, sounds artficial and unreal. You only can optimise dynamics and distortion at the same time by enlarging membrane area, but not by increasing excursion capabilities.
With regard to this ESLs can reach very high dynamics (comparable to horn speaker, but with even increased low level resolution) with exceptional low distortion values (the majority of distortion depends more on the used audio tranny than the panel itself).
If there would be any problem with the stators beeing “obstacles“ within the soundpath one should see artifacts within the the distortion measurement, right? How comes then that the distortion values of a really good panel are much lower than any other principle especially at elevated SPLs?
jauu
Calvin |
Hello Clavin,
Interesting , quick question , have you ever tested your ESl and if so what are you using to do so . |
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| a.wayne |
| quote: | Originally posted by LineArray
I think it is all about controlled motion of an area of foil or film.
Whether driven by lorentz force or electrostatically does not
matter to our ears. Using electrostatic force it is maybe more
easy to apply that force to a larger area. Using lorentz force
this is more difficult and you have to introduce voice coil like
structures on the moving foil by glueing, printing or vaporizing.
In case of a magnetic transducer with large area the shape of
the magnetic field gets more complex, because you will need
more than one N-S pole and you cannot avoid to place magnets
in front or behind the diaphragm.
Thats why a "true" ribbbon tends to implement a line source.
This is the "natural" way of constuction, which is able to
keep the diaphragm free from disturbing magnet structures in
front or behind, thereby allowing dipole radiation
if you want.
But the normal way of doing this, using a long ribbon
fixed at its short ends and folded or rippled multiply along
the short side, leads to some disadvantages.
- the ribbon produces a bowing along the long side when moving,
with maximum excursion in the middle. This is commonly solved
by introducing some more fixing points along the ribbon, if its
a really long one.
- there is a long slot at both sides of the ribbon, it cannot
contact airtight to the magnet pieces. Both slots are bordered
by the diaphragm, which is thin and sharp.This causes noise and
distortion with higher excursions.
- because of the high excursion in the middle, the magnetic
gap has to be rather deep along the whole length of the
ribbon to obtain a homogenous field, even though you would
not need that depth of the gap along the whole length concerning
excursion only.The deep magnetric gap will cause protruding edges
in front and behind the ribbon, which spoils radiation pattern
and proper acoustic coupling with the surrounding air.
- it is impossible to adjust the diaphragm to a resonant frequency
high enough for practical efficiency unless using tension along
the ribbon - which in turn causes AGEING.
All of those problems can be solved by using a folding along the long
side of the "ribbon".
- The long sides can contact the pole pieces in an airtight manner.
- Excursion is - mutually - the same over the whole length of the ribbon.
Depth of the magnetic gap can be reduced, the diaphragm can be
mounted to change almost flat into the speakers cabinets baffle.
- Resonant frequency is tuned by appropriate folding (rippling)
concerning the mass of the diaphragm material used.
- The structure can be mounted into the frame without using tension,
which yields very good long term stability.
- Even this structure will bend when driven, but the bending mode will
improve the horizontal radiation angle, because it bends along the
short sides.
To be honest, by folding the long side, there arise some technical
problems. E.g. the electrical contacts at both ends have to be designed
not to disturb the bending motion or to introduce bending in unwanted
directions. But that can be done by proper design and experience.
IMO this kind of "ribbon" is in advantage over an electrostatic
device in at least three aspects:
- capability of large linear excursion
- far less diaphragm area needed, which leads to far less
problems with unwanted vibrational modes and beaming
- unobstructed area in front and behind the diaphragm
And by the way: This is exactly the way it sounds.
Regards
|
I agree with most of what was said, with a few exceptions. Corrugation of the ribbon element is mostly determined by size and use. Different methods of corrugation will help in controlling resonance in the audio bandwidth being used . Going flat on a thin High freq ribbon will work and work well , will not do so on a 1.5 inch width foil running a wide bandwidth. Corrugation can be extremely extremely rigid to a moderate fold but running flat on a large ribbon going below 800 hz will suffer from resonance issues, distorting the sound. Some corrugation will be required if for no more than to move the resonace frequency.
AW |
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| Calvin |
Hi,
of course wayne, have the panels as well as the complete speakers been tested. :rolleyes:
Starting from quickanddirty measurements with an DLSA (cheap mic) over DAAS32 (with MB550 mic) up to MonkeyForest (with 1/4" and 1/2" B&K mics).
Measurements we did ourselves and measurements in the big measuring room (low reflectivity) of the University Aachen (measured by Anselm Goertz, who undoubtly knows how to measure things correctly ;) )
Both speakers exhibit extremely low distortion values. The big one measured lower than 0.2% in its complete frequency range (25Hz-20kHz) at a SPL of 95dB@4m. The small panel limits at 110dB@4m thereby measuring less than 0,3%THD over its working range (200Hz-20kHz). The THD values consist of nearly solely K2.
A typical measurement of SPL values is done at a distance of just 1m. For a 4m distance measurement 12dB should be added.
These are extremely low distortion values (You have to keep in mind that the measuring setup itself introduces a certain level of distortion. Distortion measurements with the DAAS32 and MB mic showed higher -still though comparably low- values, but prooved the MB mic to distort more than the B&K capsules and already more than the speaker itself.
The values found are much lower than You can reach with electrodynnamic drivers exempt maybe some big horns but those are very limited in bandwidth. The 110dB@4m of the smaller panel are very close to the maximum SPL that can be reached theoretically with a panel of this size anyway!
So I guess that my panel construction and the build quality are on a niveau that allows to draw conclusions about what a good panel might be able to ;)
Ohh, btw. to return to the question ;) The speakers have been extensively tested by many ears too. And all of them have seemed to like the sound alot :cool: At least the one who declares that he/she dislikes the sound has not spoken to me yet.
jauu
Calvin
ps
Anyway...I can just encourage You to put effort and time into a ESL project. Done well this principle is indeed very rewarding. The chances of ever returning to the unnatural, smeared and restricted sound of typical electrodynamic boxes is rather low. |
|
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| LineArray |
| quote: | Originally posted by a.wayne
I agree with most of what was said, with a few exceptions. Corrugation of the ribbon element is mostly determined by size and use. Different methods of corrugation will help in controlling resonance in the audio bandwidth being used . Going flat on a thin High freq ribbon will work and work well , will not do so on a 1.5 inch width foil running a wide bandwidth. Corrugation can be extremely extremely rigid to a moderate fold but running flat on a large ribbon going below 800 hz will suffer from resonance issues, distorting the sound. Some corrugation will be required if for no more than to move the resonace frequency.
AW |
Hi a.wayne ,
maybe a am somewhat blind but i cannot see any conflict with
what i said. I agree fully with your observations concerning
the need and the use of corrugation.
When used fairly above the resonant frequency and higher
excursion is not needed (due to diaphragm size), a
flat foil might perform very well.
In my own ribbon design i introduced that corrrugation mainly
because i wanted to get down to 800Hz with an 8mm wide
diaphragm thereby keeping a controlled motion.
Best Regards |
|
|
| a.wayne |
| quote: | Originally posted by Calvin
Hi,
of course wayne, have the panels as well as the complete speakers been tested. :rolleyes:
Starting from quickanddirty measurements with an DLSA (cheap mic) over DAAS32 (with MB550 mic) up to MonkeyForest (with 1/4" and 1/2" B&K mics).
Measurements we did ourselves and measurements in the big measuring room (low reflectivity) of the University Aachen (measured by Anselm Goertz, who undoubtly knows how to measure things correctly ;) )
Both speakers exhibit extremely low distortion values. The big one measured lower than 0.2% in its complete frequency range (25Hz-20kHz) at a SPL of 95dB@4m. The small panel limits at 110dB@4m thereby measuring less than 0,3%THD over its working range (200Hz-20kHz). The THD values consist of nearly solely K2.
A typical measurement of SPL values is done at a distance of just 1m. For a 4m distance measurement 12dB should be added.
These are extremely low distortion values (You have to keep in mind that the measuring setup itself introduces a certain level of distortion. Distortion measurements with the DAAS32 and MB mic showed higher -still though comparably low- values, but prooved the MB mic to distort more than the B&K capsules and already more than the speaker itself.
The values found are much lower than You can reach with electrodynnamic drivers exempt maybe some big horns but those are very limited in bandwidth. The 110dB@4m of the smaller panel are very close to the maximum SPL that can be reached theoretically with a panel of this size anyway!
So I guess that my panel construction and the build quality are on a niveau that allows to draw conclusions about what a good panel might be able to ;)
Ohh, btw. to return to the question ;) The speakers have been extensively tested by many ears too. And all of them have seemed to like the sound alot :cool: At least the one who declares that he/she dislikes the sound has not spoken to me yet.
jauu
Calvin
ps
Anyway...I can just encourage You to put effort and time into a ESL project. Done well this principle is indeed very rewarding. The chances of ever returning to the unnatural, smeared and restricted sound of typical electrodynamic boxes is rather low. |
LOL.
Calvin .2% THD ( 25-20K) forgive me for having a hard time in accepting that. I'm sure you and others enjoy the sound of your speakers, audio and subjectivity goes hand in hand , scratching for objectivity is the real nirvana in audio . TO say you have an ESL speaker that has .2% THD from 25-20K is unheard off on this planet or any other that i have visited in the last 10 eons, I guess you are being tongue in cheek. :D if not, then they are not an ESL , but more likely some Clingon verberator running on pulsewidth germainium. |
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| LineSource |
High efficiency DIY ribbons use 0.5" to 1" wide NdFeB magnets to create 0.5T-1T flux in the gap. What is the best solution to minimize these magnet cavity effects on a true ribbon?
Any experience or measurements with "waveguide type" front bezel curves, or RAAL type "triangle cut" bezel plates?
------------------------------------
www.transmissionaudio.com posts "extremely low" distortion measurements for ribbons
LaScala, our top-of-the-line full-range true ribbon speaker.
Total radiating area, one speaker only: 9500 sq. centimeters = 3,740 sq. in.
Whereof: LF/MID = 9000 and HF=500 square centimeters respectively.
Max SPL for any frequency within 30Hz to 30kHz: Limited by Xmax only.
Total height: 220 cm (86 in.) Total width: 95 cm (37.4 in.)
Number of 2" wide ribbons: 9. Number of 1" wide ribbons: 1
Total ribbon length: 20 meters (787 in.).
Total magnet line length: 22 meters (866 in.)
Sensitivity: Ultra Propulsion mode: 90dB/1W/1meter;
System resonance: 4Hz.
Impedance: 8,0 Ohm at any frequency 10Hz to 40kHz (Ultra Propulsion mode);
Distortion: typically 0,05% at 110dB SPL. |
|
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| LineSource |
High efficiency DIY ribbons use 0.5" to 1" wide NdFeB magnets to create 0.5T-1T flux in the gap. What is the best solution to minimize these magnet cavity effects on a true ribbon?
Any experience or measurements with "waveguide type" front bezel curves, or RAAL type "triangle cut" bezel plates? |
|
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| LineArray |
When using "conventional" ribbon shape the answer is
simple: The problem stays.
Both solutions you mention (sawtooth border of front bezel,
wave guide) seem applicable to deal with that.
Maybe covering the magnet/bezel using soft and porous
materials can help too.
I used a waveguide in my own design once and was not
statisfied with the result.
I heard the Crevasse at an audio fair some years ago.
To me it sounded rather warm and balanced in the
midrange but also dull in the highs.
There was a lack of resolution and "dircectness" which
made me wonder why to use a ribbon at all ... But i do not
think that the waveguide/horn was responsible for that.
Although it is a very impressive and aesthetical design
to me, but was one of the greatest disappointments
sonically.
With a different transducer design i think there would be
higher potential. Maybe they changed somewhat in the last
years, i don't know. The Crevasse transducer that i have seen
had more than one conducting lane on its diaphragm,
so we can discuss if it is still a "true ribbon".
I don't like the term "true ribbon" by myself, but if used i would
apply it to those constructions, which have only one conducting
lane, which is the made of the diaphragm material itself.
Personally i would not bind "truth" to the way the ribbon
is suspendend/folded/currugated.
To overcome/attenuate the protruding magnets by transducer
design, like i explained before, is the way to solve
the problem at its roots IMO. |
|
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| Calvin |
Hi,
@wayne
Could you please stop citing complete texts? :mad:
Sorry, that I don“t lough along with you.
I could understand your reaction if I had “faked“ the measurement myself. But no, the measurement was executed by Prof.Dr. A.Goertz who is a well known capacity within the audio-scene and it took place on may, 19th. 2008 in the anechoic room at the RWTH Aachen which is one of the top universities in Germany for electronics and acoustics.
And simply because of You haven“t seen or heard of a speaker that performs so well doesn“t mean it doesn“t exist. I and all those who saw and heard it yet, know it exists. :D
jauu
Calvin |
|
|
| a.wayne |
| quote: | Originally posted by LineSource
High efficiency DIY ribbons use 0.5" to 1" wide NdFeB magnets to create 0.5T-1T flux in the gap. What is the best solution to minimize these magnet cavity effects on a true ribbon?
Any experience or measurements with "waveguide type" front bezel curves, or RAAL type "triangle cut" bezel plates? |
| quote: | Originally posted by LineArray
When using "conventional" ribbon shape the answer is
simple: The problem stays.
Both solutions you mention (sawtooth border of front bezel,
wave guide) seem applicable to deal with that.
Maybe covering the magnet/bezel using soft and porous
materials can help too.
I used a waveguide in my own design once and was not
statisfied with the result.
I heard the Crevasse at an audio fair some years ago.
To me it sounded rather warm and balanced in the
midrange but also dull in the highs.
There was a lack of resolution and "dircectness" which
made me wonder why to use a ribbon at all ... But i do not
think that the waveguide/horn was responsible for that.
Although it is a very impressive and aesthetical design
to me, but was one of the greatest disappointments
sonically.
With a different transducer design i think there would be
higher potential. Maybe they changed somewhat in the last
years, i don't know. The Crevasse transducer that i have seen
had more than one conducting lane on its diaphragm,
so we can discuss if it is still a "true ribbon".
I don't like the term "true ribbon" by myself, but if used i would
apply it to those constructions, which have only one conducting
lane, which is the made of the diaphragm material itself.
Personally i would not bind "truth" to the way the ribbon
is suspendend/folded/currugated.
To overcome/attenuate the protruding magnets by transducer
design, like i explained before, is the way to solve
the problem at its roots IMO. |
Linearray ,
I can concur with what you say, as we did come to the same conclusion. We ended up using a very short wave guide which helped, but did have a very slight change in directivity , we did pick up 1.8 db gain. and felt the gains outwayed the negative.
With a longer wave guide as illustrated above , our conclusions where the same as yours , it destroyed the sound of the speakers. What also helped was adding wings recessed 1 inch behind the front baffle and at an 'angle of no more than 45 Deg. Anything above this picked up more gain but at the expense of becoming a monolith and had too much boundary effect making the speaker less able to Image , less likely to "disappear".kinda like a big ESL where the image size is big all the time reduced dynamics ( micro and macro)
Calvin ,
Relax , I 'm here to have fun and for mutual technical exchange . No offense was intended , I do apologize if you took it differently.
My intentions was not directed @ Goertz or his testing facility , just saying regardless of how you put it . i have a hard time believing you have a speaker that has .2 % THD when measured from 25-20 k. Could you please post your SPL Sweep or any data from the lab... it would help me come up to speed as to where you are with your ESL.................
A.Wayne |
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| LineSource |
RAAL's "raindrop" tweeter designed to be crossed over 3,000 Hz uses a "waveguide" type bezel for diffraction and directionality control instead of the sawtooth metal front bezel of their higher volume ribbons which are spec'ed for 1,500 Hz crossover.
Would the raindrop waveguide be a more expensive solution that can reduce distortion over the lower cost sawtooth bezel, or.....
The raindrop waveguide bezel might be used to increase SPL to match a compression horn efficiency.
The raindrop waveguid | | | | | |
