Tranquility Bass Posted March 20, 2016 Share Posted March 20, 2016 It's a novel approach but wouldn't those strings resonate just like they do on a piano ? cheers Link to comment Share on other sites More sharing options...
jazzman53 Posted March 20, 2016 Author Share Posted March 20, 2016 It's a novel approach but wouldn't those strings resonate just like they do on a piano ? cheers Hello David, Your question is a good one. And since I've not built panels like these before, I can't know if their resonances will be objectionable until I hear them playing. One thing is for sure; there will be multiple resonances occurring, including the wires. Unlike a piano or guitar string however, the wires here are not in tension. My thoughts on this (correct or not) is as follows: Whereas a piano wire sounds a constant frequency determined by its tension and length, the wires in my ESL panel will likely resonate at varying frequencies, in response to and in anti-phase to the electrostatic forces pushing against the wires to move the diaphragm and the air mass coupled to it. The wires themselves will also have a resonance peak at their fundamental; in this case determined by the length between the lattice supports and wire stiffness. In turn, the wires couple to the wooden lattice, causing it to resonate at same frequencies with a peak occurring at the lattice's fundamental [tuning fork] frequency. I'm thinking that, like all other panels I've built, the predominant resonance will be the diaphragm's fundamental (drum head) resonance, which should occur somewhere around 80Hz in this panel. The drum head resonance is a serious challenge in an ESL, especially in full range ESL's. Mine will be a hybrid ESL with a conventional woofer crossing in at 220Hz via an active 48db/octave digital filter. My rule of thumb to prevent exiting the drum head resonance is to set the crossover at least 1 octave above resonance if using a 48db filter or 2 octaves above if using a 24db filter. Really, my only concern is that these new stators are so much lighter in weight than any I've built before. I recall on my first ESL, placing my palm against its heavy perforated steel stator and feeling it's surprisingly strong vibration. These new wood-lattice/copper wire stators are much lighter so it's a given that they will vibrated much more. In my earlier panels, the remaining resonances were not audibly noticeable once the drum head resonance was tamed. It remains to be seen whether this much lighter panel will have objectionable resonances. If it does, my backup plan is to attach some adhesive backed lead foil to the rear stator slats to add some mass. Charlie Link to comment Share on other sites More sharing options...
Al.M Posted March 23, 2016 Share Posted March 23, 2016 (edited) I tend to agree with Statman. I have had a standard pair of Acoustat 121 (two panel versions like a half a 2+2, not the 1+1 setup) for the last 12-15 years and I always come back to them for naturalness and imaging and general all round box ticking. In my 5 x 4m room it works well in a near field setup. Mine have imaging, naturalness and midrange similar to a Quad 57 with better top & bottom end and drive so I don't want to mess with that unless for the better. I wouldn't mind getting some further advice from others on how to improve standard Acoustats and tweak them without radical changes. Some Medallion units would be good but very hard to find in 230V. I could do with a little more extension in the treble. I have heard that the Model 3 & 4 with too many side by side panels mucked the imaging up. I also had the Active Model 4 with servo tube amps, which had a lot of drive but not as musical and imaged as well as my standard 121s. Also had the Nakamichi Dragons, again very good but not enough ESL going on for me to give the full goose bumps effect. I have been doing shootouts alongside Acoustat Spectra 11, Magnapan 2.6 and Ambience 1600 and each have their benefits. Edited March 23, 2016 by Al.M Link to comment Share on other sites More sharing options...
statman Posted March 23, 2016 Share Posted March 23, 2016 I wouldn't mind getting some further advice from others on how to improve standard Acoustats and tweak them without radical changes. Some Medallion units would be good but very hard to find in 230V. I could do with a little more extension in the treble. Boosting the bias will help and also splitting the crossover into two so as to be able to bi-amp, however your bias supply is probably old and tired, just restoring it will make it new again, with a big improvement and then you want be able to listen to anything else. Also don't forget to vacuum them now and again. Jazzman, very impressive work, wish I had your knowledge ,patience and time ! Link to comment Share on other sites More sharing options...
Tranquility Bass Posted March 23, 2016 Share Posted March 23, 2016 Hello David, Your question is a good one. And since I've not built panels like these before, I can't know if their resonances will be objectionable until I hear them playing. One thing is for sure; there will be multiple resonances occurring, including the wires. Unlike a piano or guitar string however, the wires here are not in tension. My thoughts on this (correct or not) is as follows: Whereas a piano wire sounds a constant frequency determined by its tension and length, the wires in my ESL panel will likely resonate at varying frequencies, in response to and in anti-phase to the electrostatic forces pushing against the wires to move the diaphragm and the air mass coupled to it. The wires themselves will also have a resonance peak at their fundamental; in this case determined by the length between the lattice supports and wire stiffness. In turn, the wires couple to the wooden lattice, causing it to resonate at same frequencies with a peak occurring at the lattice's fundamental [tuning fork] frequency. I'm thinking that, like all other panels I've built, the predominant resonance will be the diaphragm's fundamental (drum head) resonance, which should occur somewhere around 80Hz in this panel. The drum head resonance is a serious challenge in an ESL, especially in full range ESL's. Mine will be a hybrid ESL with a conventional woofer crossing in at 220Hz via an active 48db/octave digital filter. My rule of thumb to prevent exiting the drum head resonance is to set the crossover at least 1 octave above resonance if using a 48db filter or 2 octaves above if using a 24db filter. Really, my only concern is that these new stators are so much lighter in weight than any I've built before. I recall on my first ESL, placing my palm against its heavy perforated steel stator and feeling it's surprisingly strong vibration. These new wood-lattice/copper wire stators are much lighter so it's a given that they will vibrated much more. In my earlier panels, the remaining resonances were not audibly noticeable once the drum head resonance was tamed. It remains to be seen whether this much lighter panel will have objectionable resonances. If it does, my backup plan is to attach some adhesive backed lead foil to the rear stator slats to add some mass. Charlie I was thinking that if the wooden struts were arranged in a zig-zag fashion rather than straight across then the resonances of each wire would be different and diffused across the spectrum rather than peaking at one frequency cheers Link to comment Share on other sites More sharing options...
Sir Rab of Everest Posted March 23, 2016 Share Posted March 23, 2016 Also don't forget to vacuum them now and again. ...and, if you're game, retensioning them with a heat gun. Link to comment Share on other sites More sharing options...
jazzman53 Posted March 24, 2016 Author Share Posted March 24, 2016 Update 3/24/16: The stators are finished and the diaphragms were installed and conductive coatings applied this afternoon. The coatings need twenty four hours to dry and then I can assemble the panels. The resistors and bread boards for the RC networks were ordered today--- still gotta build the networks. I figure another week to wrap this up. Photo 1: Bonding stator to the tensioned diaphragm, on my pneumatic (bike tube) tensioning jig. Diaphragms were tensioned to 1.4% elongation. Photo 2: Diaphragm installed 3 Link to comment Share on other sites More sharing options...
statman Posted March 29, 2016 Share Posted March 29, 2016 Man i would love to hear this when it gets fired up! Link to comment Share on other sites More sharing options...
jazzman53 Posted March 29, 2016 Author Share Posted March 29, 2016 I may be able to finish this project tonight. One panel is already mounted into the speaker frame. Now just have to wire up the segmentation resistors to the other panel and get it mounted and they'll be ready to play. Too bad everyone won't be able to hear them but maybe I can post a Youtube video. 1 Link to comment Share on other sites More sharing options...
jazzman53 Posted March 30, 2016 Author Share Posted March 30, 2016 My speakers are finished and playing as I'm writing this. My expectations are exceeded: Seamless, pristine highs, slam, imaging... all wonderful right out of the box. I haven't even done any EQ'ing and they're lovely. Not to mention they look really sexy too. 12 Link to comment Share on other sites More sharing options...
Mr 57 Posted March 30, 2016 Share Posted March 30, 2016 Gobsmacked ! They are simply stunning, every detail looks truly fantastic...WOW ! For an ESL tragic, these would truly impress ....I love these Link to comment Share on other sites More sharing options...
Rob181 Posted March 30, 2016 Share Posted March 30, 2016 I have been following this thread since the beginning.... These are THE BEST DIY speakers I have ever seen...& the fact that they are ESL's makes this build a master peice... Congratulations Sir...I sincerely hope they sound as good as they look... OH...& love the sub... 2 Link to comment Share on other sites More sharing options...
Volunteer sir sanders zingmore Posted March 30, 2016 Volunteer Share Posted March 30, 2016 Wow! Link to comment Share on other sites More sharing options...
Sir Rab of Everest Posted March 30, 2016 Share Posted March 30, 2016 Absolutely stunning, Jazzman! [emoji177][emoji177] Link to comment Share on other sites More sharing options...
jazzman53 Posted June 30, 2017 Author Share Posted June 30, 2017 (edited) Thank you all for the kind remarks. Now an update: It’s been over a year since I completed my segmented wire stator ESL project and these speakers continue to amaze me. They have clarity and speed in spades, of course. Imaging is slightly less precise than my old flat perf-metal panels, yet still very good, and their dispersion is superb-- wider than a curved panel and smoother (no discernable lobing) than any conventional speakers I’ve heard. The segmentation scheme really works well. Another advantage of segmentation is a much easier load for the amp, as the impedance is predominantly resistive below the top two octaves; whereas a conventional ESL’s load is predominantly capacitance. Segmentation also renders the panel’s frequency response essentially flat; whereas a conventional tall/thin ESL panel needs a lot of EQ’ing to balance its rising response. I can’t imagine going any other way now. Every year in the mountains of North Carolina (USA) there’s a two-week long festival for owners of Carver audio gear, called Carverfest. This past year I rented a van and hauled my new speakers and Carver gear to Carverfest. Everyone there was amazed and one fellow offered me $10K cash for my speakers but I wouldn’t sell. And the Bobfather (a.k.a. Bob Carver) was equally amazed (high praise indeed). BTW I have CAD drawings of my stretching jigs and speaker components which I will gladly share with anyone interested. Here's a link to a short cell phone video of my speakers playing at Carverfest Edited June 30, 2017 by jazzman53 8 Link to comment Share on other sites More sharing options...
PicoWattson Posted July 2, 2017 Share Posted July 2, 2017 Who wouldn't be proud of a shot like that with the great man, congratulations Jazzman. Frequent visitor to your site and you have inspired me to attempt this build. Anything easier than my Kingsound ESLs to drive would give me would give me a greater choice in amplification. Thanks for sharing. Link to comment Share on other sites More sharing options...
jazzman53 Posted July 2, 2017 Author Share Posted July 2, 2017 15 hours ago, PicoWattson said: Who wouldn't be proud of a shot like that with the great man, congratulations Jazzman. Frequent visitor to your site and you have inspired me to attempt this build. Anything easier than my Kingsound ESLs to drive would give me would give me a greater choice in amplification. Thanks for sharing. Thanks Hank, If you do pull the trigger on a speaker build, feel free to contact me. I may not be much help but you can always count on me for immoral support :-) BTW, my speakers will be the feature article in the September 2017 issue of AudioXpress magazine. Link to comment Share on other sites More sharing options...
jazzman53 Posted August 11, 2017 Author Share Posted August 11, 2017 The September 2017 online edition of AudioXpress magazine, containing my speaker article, came out today. I was a little disappointed that my speaker wasn't on the cover (commercial speakers won out there) but they did a very nice 8-page layout of my speaker article inside. Below are the cover and the first page of my article: 5 Link to comment Share on other sites More sharing options...
Rob181 Posted August 11, 2017 Share Posted August 11, 2017 For not the first time... You...Sir...a genius... 1 Link to comment Share on other sites More sharing options...
jazzman53 Posted August 11, 2017 Author Share Posted August 11, 2017 3 hours ago, Rob181 said: For not the first time... You...Sir...a genius... I wish... the real ESL gurus are Steve Bolser and Rod White (a.k.a. Bolserst and Golfnut) from the DIY Forum. Link to comment Share on other sites More sharing options...
LogicprObe Posted August 11, 2017 Share Posted August 11, 2017 Great stuff mate!..............and you're right! They should have been on the cover. Link to comment Share on other sites More sharing options...
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