I've begun my first foray into planar / ribbon speaker design. I built a few simple prototypes but I'm looking to expand to a more sophisticated setup.
Does anyone know of a resource or know of some equations which govern frequency response of a ribbon or planar speaker?
I've noticed through reading that the width of the ribbon greatly affects the bass response but I'd love to find a way to actually calculate the -3dB point of the low end.
Any input would be greatly appreciated!
Thanks,
J
Does anyone know of a resource or know of some equations which govern frequency response of a ribbon or planar speaker?
I've noticed through reading that the width of the ribbon greatly affects the bass response but I'd love to find a way to actually calculate the -3dB point of the low end.
Any input would be greatly appreciated!
Thanks,
J
Hi,
You wish to get hold of a copy of Ribbon Loudspeakers... by Justus Verhagen. This has plenty of theory.
BKAA65 - Ribbon Loudspeakers
Best wishes.
Iain.
Any book on The Calculus of Variations would cover the partial differential equation which describes the motion of a vibrating elastic membrane, and the solution of the equation.
Here's a free one, on line, found with a search on google.com for "calculus of variations membrane" (search results here: calculus of variations membrane - Google Search ):
Calculus of variations: with ... - Google Books
Here's another one:
Calculus of variations - Google Books
In the first one, they even solve for the eigenvalues and eigenfunctions of a rectangular membrane of uniform density, in Section 9-8, starting on page 160.
But it sure seems like setting up a finite elements model of the physical system and simulating it in software might be the best way to go. (Then later you could, for example, add magnets and conductors and a subset of Maxwell's Equations and apply signals and measure the simulated response, etc.)
Apparently there are even some Java applets on line that simulate vibrating rectangular membranes. I haven't looked at any of them but links to them are included in the google search results for "vibrating membrane simulation" ( vibrating membrane simulation - Google Search ). You can add the word "rectangular" to that search and try it again.
Cheers,
Tom
Here's a free one, on line, found with a search on google.com for "calculus of variations membrane" (search results here: calculus of variations membrane - Google Search ):
Calculus of variations: with ... - Google Books
Here's another one:
Calculus of variations - Google Books
In the first one, they even solve for the eigenvalues and eigenfunctions of a rectangular membrane of uniform density, in Section 9-8, starting on page 160.
But it sure seems like setting up a finite elements model of the physical system and simulating it in software might be the best way to go. (Then later you could, for example, add magnets and conductors and a subset of Maxwell's Equations and apply signals and measure the simulated response, etc.)
Apparently there are even some Java applets on line that simulate vibrating rectangular membranes. I haven't looked at any of them but links to them are included in the google search results for "vibrating membrane simulation" ( vibrating membrane simulation - Google Search ). You can add the word "rectangular" to that search and try it again.
Cheers,
Tom
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Ok, I wonder if a new version is about to appear. In the meantime, how about having a look at some relevant USA Patents, which have appropriate information. Use International Classification H04R$ and use ribbon, planar etc for description. You can also use inventor names like: Levitsky, Bohlender, Graebener, de Haan. The link to the AES paper by Phil has a lot of useful information, about the Stage Accompany driver. I am sure that you will discover that the real secret, is the material technology. Do you have a magnetic modelling program? FEMM is worth checking out.
http://www.stageaccompany.com/download/files/aes8535.pdf
Iain.
(Ack. Apparently you didn't do a google search for the author's name.)
Maybe Dr. Verhagen has a copy he would sell you. Why not call or email him? Contact info: Purest Music: About Us
Also, I found a full download of that book, in RAR format: Ribbon loudspeakers Justus V. Verhagen » Full Rapidshare Hotfile Megaupload Megashare Downloads by LatestDL
Cheers,
Tom
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I appreciate the effort but I hope you didn't click the link. It's definitely a virus.
Maybe I'll give the author a try as you suggest. It's worth a shot I suppose.
Luckily someone I know works for a library inter-loan program and may be able to get a hold of it to me. (Not sure why I didn't think of that to begin with).
Thanks for the google books link, it definitely seems like a worthwhile read. It's exciting getting back into this stuff.
Cheers,
J
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