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Electrostatic speakers?
- Thread starter Pearljam5000
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Is the primary reason why electrostats measure poorly because they're dipole? If so what about JansZen's e-stats? They're enclosed in a backbox w/ glass fill in them supposedly. They're also working on a headphone now. I've always wondered what directivity of an e-stat is supposed to look like, curious if they're hyper focused and narrow or more like AMT / Ribbons that are a little more wide.
Hey I just replaced the diaphragm in one of this ML Theater panels. ML doesn't support these old speakers anymore but the panel can be rebuilt if it ever goes bad. The one I just fixed had a dead zone on one end. Here's my write-up on that panel rebuild: https://jazzman-esl-page.blogspot.com/2011/11/compensating-diplole-phase-cancellation.html
You nailed it.
Stats need a lot more surface area, which tends to beaming, but there are ways to mitigate the directivity.
I have some info about this on my DIY ESL website here:
Jazzman's DIY Electrostatic Loudspeaker Page
DIY electrostatic loudspeakers
jazzman-esl-page.blogspot.com
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Because of this thread, I have just looked at the Sanders Model 10. Going by the speil, surely the end of times speaker? Performance, warranty etc.
A customer has some Sanders, I would definitely make sure you can hear them ( or any electrostatic) in your own place before purchase.
Keith
Keith
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As a "forever interested in electrostatic speakers" person, since seeing Peter Walker demoing 57's at a Harrogate hi-fi show many years age, I have always considered they would be too large for any home that I have owned. But I did think that if the Sanders do what they are claimed to do, what else could one need? Physical space for them, aside.
I have heard many designs but have yet to be convinced, I am sure though that in 1957 they were groundbreaking.
Keith
Keith
To the best of my knowledge, only the Sanders ESL has a lifetime warranty. The industry-standard is 5 years.
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Even Bryston is "only" 20 years!
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My Harrogate show would have been in the mid to late seventies. I don't remember being particularly taken with the demo, but it was good to see a hi-fi God!
Curved panels solve the beaming problem.You nailed it.
Stats need a lot more surface area, which tends to beaming, but there are ways to mitigate the directivity.
I have some info about this on my DIY ESL website here:
Jazzman's DIY Electrostatic Loudspeaker Page
DIY electrostatic loudspeakers
Yes, but the diaphragm of a curved panel electrostat is subjected to more stress than the diaphragm of a flat panel, segmented flat panel, or a segmented-curved panel electrostat.
You can think of a curved panel as a vertical section of an expanding cylinder. As the panel moves outward, it is tensioned. As the panel moves inward, the tension is relaxed. This becomes more of an issue as diaphragm excursion increases, such as at bass frequencies and/or high sound pressure levels.
The best unsmoothed in-room loudspeaker measurements I have ever seen were of a segmented-curved-panel electrostat (by SoundLab, dealer disclaimer). In this photo you can see the flat vertical facets, each made up of many individual cells of different heights:
Curving the panel is one way to mitigate beaming. It's not perfect insofar as it introduces some drive asymmetries, but it's effective without addiing a lot of complexity and cost.
Another method sections a flat panel into a narrow treble section and a wider mid/bass section, each separately powered thru a crossover.
Yet another method is symmetrical electrical segmentation, which is only feasible with flat-panel wire-stator designs, but it allows tailoring the dispersion pattern however one likes. This is now my prefered design but it does add complexity and cost, not to mention a lot of work.
Narrow dispersion isn't necessarily a bad thing (Sanders speakers sound fantastic in the sweet spot), nor is wide dispersion necessarily a good thing.
Wide dispersion trades away pinpoint imaging and narrow dispersion puts your head in a vise, so pick your poison. Either way; it's gonna be a compromise.
I once built a segmented ESL from welding rods that had switch-selectable narrow and wide dispersion modes. The switch-mode feature worked remarkably well, and it was fun for a while, but the novelty wore off pretty quickly because I had to power-down to switch modes (lest high voltage corona destroy the switch) and then re-EQ the panel each time because each mode had a unique response curve. It sounded wonderful but the panel was butt-ugly, and switching modes was imparactical so I omitted that feature in subsequent builds.
Here's a link to the switch-mode welding rod panels: http://jazzman-esl-page.blogspot.com/2008/03/a-segmented-wire-stator-esl-with.html
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MRC01
Major Contributor
Partially, at least.
In the related case of planar magnetics, ribbon tweeters do this job. They are big enough (5' long) to cross over at about 1700 Hz, relatively low for a tweeter. So you get nice even distribution through the treble.
Yet that doesn't solve the problem completely, because the midrange panel is about 14" wide which is the wavelength of about 900 Hz. So the dispersion would be increasingly non-uniform from 900 to 1700 Hz. I believe this change in dispersion is a likely cause for why the panel to ribbon transition can be audible.
eddantes
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I owned a pair of Magnepan 2.5r... For all that they did right, or at least impressively... that was not a speaker to listen to outside the sweetspot. Oh... and because they are the size of two screen doors - it was a rather slender sweetspot. Not electrostatics per-se, but to echo the above points - large planar seakers are... an acquired taste.
MRC01
Major Contributor
My numbers above are for the 3.6/R, but the overall principle holds for any of the models that have the ribbon tweeter. The ones that don't have that tweeter (such as the LRS) would have non-uniform beamy treble like a flat panel electrostat, as @amirm 's measurements confirmed: https://www.audiosciencereview.com/forum/index.php?threads/magnepan-lrs-speaker-review.16068/
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