La Folia Magnetostatics - has anyone seen these before?

[Spasticteapot]

Link to Plans
More Detailed Description

If only the translation was better!

Anyway, I was wondering if anyone has seen these before. Although the original author had good luck with very thin foil on mylar, I was wondering if instead a mask could be used, and a mixture of diluted conductive glue and super-fine powdered copper could be airbrushed on in a thin layer to form the segmented semi-ribbon design. (In other words, super-thin conductive paint.)

I'm not sure of how well this would work, but I do know that a bunch of neodiyum magnets are at least slightly less dangerous than the thousands of volts required for electrostatics.

[SY]

This was the subject of an interesting Speaker Builder article back in (I think) the late '80s. IIRC, the author of that piece is a member here.

[stokessd]

Originally posted by Spasticteapot
Link to Plans
More Detailed Description

I'm not sure of how well this would work, but I do know that a bunch of neodiyum magnets are at least slightly less dangerous than the thousands of volts required for electrostatics.

If you don't mess with your ESL's when the audio signal is live, the ESL's are pretty benign. Sure, you can shock yourself a little on the HV supply, but they tend to be so wimpy that they don't bite very hard. However, I've gotten a couple significant pinches from Neo magnets. 10 minutes after the bite from the ESL supply, I've forgotten it, but 10 minutes after a bite from a neo, the blood blister is just starting to form...

That said, I also have a soft spot for planar magnet speakers as well. My first high end “deflowering” was with Maggies. And I owned the Eminent Technology LFT-6’s for a number of years. I’ve considered building my own on a number of occasions, but my ESL’s work so well that it takes the wind out of my sails.

Sheldon

[steenoe]

La Folia Magnetostatics - has anyone seen these before?

The answer is yes. An old friend of mine has been building speakers like that for many years. I think I posted a few pic's way back, I will link you to them when I find them.
My friend has a pair of those, bigger than the average door
The normal reaction is "WoW" when ppl hear them. It takes a poweramp of dimensions to drive them though

Steen

[steenoe]

Here is, first of all a link to a swede that really knows what he is doing http://www.dahlbergaudiodesign.se/
Not that the other guy doesn't!
I think the best way to implement the Magnetostats is using them for the topend! If you want a fullrange, it really puts demands on your poweramp. They are really powerhungry devils.
Here is the link to the pic I mentioned:
http://www.diyaudio.com/forums/showt...150#post684150 Those speakers are driven by the Threshold, mentioned in the thread.
They sound great, but you are warned
Dahlberg's ribbon tweeter looks really cool
My overall judgement is that if a speaker like that has enough power to draw from, they sound great. Crystal clear like you wouldnt beleive.
I am certain that the details are more airy and pinned out in the topend, than you could ever hope for in a normal pair of speakers
I saw and heard a good deal of implementations of the Magnetostats as they were quite popular here in DK some years ago. The best ones generally used normal bass speakers for the bottomend.
Another friend of mine actually has a pair like the ones in the pic also, driven by a Krell KSA 100, believe it or not!! They sound like wonders, too!

Steen

[Henrik Juhl]

Hello Spasticteapot (what kind of name is that anyway...)

The concept was quite popular in DK in the late eighties as DIY project. Did build a prototype - you may find additional story and some usefull links on my homepage:
http://www.juhlweb.dk/diy_loudspeake...tm#La%20Folita - look under the 'La Folita' heading, in case my bookmark does not work.

They had potential, and with the improved access to powerful magnets they may even be better off today.

[Spasticteapot]

Originally posted by steenoe
Here is, first of all a link to a swede that really knows what he is doing http://www.dahlbergaudiodesign.se/
Not that the other guy doesn't!
I think the best way to implement the Magnetostats is using them for the topend! If you want a fullrange, it really puts demands on your poweramp. They are really powerhungry devils.
Here is the link to the pic I mentioned:
http://www.diyaudio.com/forums/showt...150#post684150 Those speakers are driven by the Threshold, mentioned in the thread.
They sound great, but you are warned
Dahlberg's ribbon tweeter looks really cool
My overall judgement is that if a speaker like that has enough power to draw from, they sound great. Crystal clear like you wouldnt beleive.
I am certain that the details are more airy and pinned out in the topend, than you could ever hope for in a normal pair of speakers
I saw and heard a good deal of implementations of the Magnetostats as they were quite popular here in DK some years ago. The best ones generally used normal bass speakers for the bottomend.
Another friend of mine actually has a pair like the ones in the pic also, driven by a Krell KSA 100, believe it or not!! They sound like wonders, too!

Steen

I have a set of 4 22v 300+VA transformers, some really big heastinks, and plans for a bridged LM4780 gainclone capable of pushing 180 watts or more. Bring it on.


I'd need someone else to test it, but I think that "printed" ribbons could work much better than the standard variety. By making the "ribbons" on the magnetostatic design much more narrow and having more of them, impeadance and efficiency could be greatly improved.

As long as we're discussing crazy speaker designs, what about the flat-coils used by the ApexJr Ribbon Tweeter? They have a large, thin spiral on mylar. What if a similar design could be employed, but with , say, a 3" coil in the middle of a 4' panel? (Some huge neodiyum magnets would need to be positioned on both sides of the coil, but at least the motor would be pretty simple.)

Also, what's the advantage of using aluminum foil over, say, 50 guage copper wire?

[steenoe]

Bring it on.

None of this was meant as a challenge! I for one, cant help you any further. Allthough I will give you a little hint: If you plan to run roomdividers like the ones in my pic with a chipamp, good luck and I hope you have big heatsinks, (and a robust psu)

Steen

[Samppo]

Interesting thread and pictures..

Have seen the lafolia webpage and the more detailed article (Egevang Rib) published in Swedish/Danish high fidelity magazine.
As i've understood these were very popular in the Nordic countries in the late 80's/early 90's, with alot of speakers built.
Am also building a pair but it's proceeding really slowly. For the tweeter and woofer section i have the magnets glued to the steel and some of the frame parts available and done, but that's about it.
Biggest problem for now is to locate compression springs somewhere at an affordable price. They tend to be really expensive ordered in small amount, which you only need for this project