I would ask anyone with the stacked panels to try this and let me know if you have similar results. It is interesting because I can vary the amount of high frequency information by the angle of the tilt. Chin to chest is a bit shrill, but while looking at the base of the speakers (45 degrees?) it seems just right. I don't notice it on all music as pronounced as I do on certain songs. Caveat- I'm not insane, I'm just an audiophile. Ok...i think I just contradicted myself. ��
I currently own Spectra 4400's (but have also owned Model 1+1 and Model 6, and I have listened extensively to Model 2+2 and Spectra 66/6600 as well as most of the single-stack models) and in over 30 years of listening exclusively to Acoustats I have never experienced what you are describing in any of the many rooms in which the speakers were playing. In fact, I think one of the hallmarks of the double-stacked Acoustats is their evenness of vertical dispersion. They tend to have a virtually identical sound either sitting or standing, and yes, even chin-down or chin-up.
I cannot think of any particular malfunction of your speakers that would be responsible for this, so I can only assume this is caused by room acoustics and/or a unusual characteristic of your hearing. I do appreciate that your discovery is alarming and most disconcerting!
Do you know if your speakers have ever been modified, rewired, or are in anyway not factory-original? With speakers this old, many things are possible, especially when they may have gone through several owners.
Questions for all you diy'ers. Is there any material between the panels and the wooden frames for dampening? Would you see any advantage to having a custom cut piece of rubber/foam around the perimeter of the panel with precut mounting holes that goes between the panel and the frame? This would give even dampening around the perimeter of the panel. Would this perhaps be enough dampening to eliminate the felt pads? Why are the felt pads solid? Would felt with holes serve the same purpose, but still allow sound to pass through? I ask because I have a number of waterjets that can cut a myriad of different materials. I would love to try different materials and ideas. I've just never opened mine up to see the inner workings.
Adding material as you suggest would only serve to absorb energy from the membrane itself. This would be counter intuitive. The felt pads are there to stop LF resonance of the panels. If you tuned the rigidity of the substrate to cancel it, I think you would lose sensitivity and probably skew FR as well. The more rigid, the better I would think as that results in increased kinetic energy, the whole point behind ESLs. However, I wonder if anyone has tried adding structure to the backs of the panels in lieu of the felt, such as gluing an additional louver with say for example something like 3 or 4 inch grid, maybe 2 to 3 inches deep? That would add some rigidity
Apparently some ESLs have arcing problems in high humidity. Some are also on metal frames. There is no discourse I have found regarding seasonal expansion/contraction problems. There must be a relatively wide range of tolerance with the Acoustats since the simple remedy to tighten the membrane with a hair dryer doesn't prescribe or determine the exact amount of tension achieved. So it's clear that small differences don't matter enough to be audible.
I've only seen it mentioned, no actual instructions. But for sure you'd need to get right up close so that would mean removing the grill cloth. My Monitor 3s have a removable grill on a frame on the back side. The sock type would need some disassembly such as my Model 3s.
In any case, I would not attempt re-tensioning unless they are visibly loose/wrinkled, or buzzing/rattling on loud transients. If they don't need it, you may end up flaking/loosening some of the conductive material by over- tensioning past their original state.
Try this http://www.diyaudio.com/forums/planars-exotics/183168-acoustat-answer-man-here-91.html#post3851274. You will need a heat gun not a hair dryer. Also recommended that you practice before you actually do the panel. Keep the heat gun moving or you will melt panel/Mylar.
Always keep the heat gun moving and on low heat, I think a heat gun on high would be asking for trouble, but I guess it depends on the heat gun.
I did mine years back with no problem with some encouragement from Moray James.
But I did melt a buddies panel when doing his, it was a tough day on my ego
I did mine years back with no problem with some encouragement from Moray James.
But I did melt a buddies panel when doing his, it was a tough day on my ego
Andy can state again...but I think the coating was put on after the mylar was heated ...
In the pic you can see the cracking that can happen when any ESL mylar is re-headed... if the coating pulls to far in the right spot.. you can Kill bias feed to the panel....good luck
In the pic you can see the cracking that can happen when any ESL mylar is re-headed... if the coating pulls to far in the right spot.. you can Kill bias feed to the panel....good luck
Attachments
![Nov20_2002_01%2024[1].jpg](/community/data/attachments/554/554164-877ff65ae1473f443dd7fb1503c59eac.jpg)
I have never taken my 2+2's apart so forgive me if this is a ridiculous question. It appears that there is perhaps a 2 "square" (plastic grid) buffer around the perimeter of each panel where it screws to the frame. Would there be any advantage to fabricating a metal "frame" 1 or 2 "squares" wide for each side of the panel so that:
A) The screw force could be distributed more evenly around the perimeter of the panel?
B) Additional screws could be added to stiffen the panel if desired?
A) The screw force could be distributed more evenly around the perimeter of the panel?
B) Additional screws could be added to stiffen the panel if desired?
I just got a pr of the last Model 3s the tall one look like the Spectra with 5 wire panels.... the owner had added 1/4"felt padding... all the way around under the panels... an added small rubber washer to each of the 8 bolt....it killed the high frequency ...I pulled all of of his added felt an rubber off...thay came back to life......
I feel after 30 years of owning Acoustats an doing every mod I could find to get better sound.... Jim Strickland...an his team got it right with his stock panels setup...
All just one mans finding....
P.S.....But like all things in higher end Audio....if you dont go you wont know...
But after all the years of moding Acoustat....I have No Regrets!
I feel after 30 years of owning Acoustats an doing every mod I could find to get better sound.... Jim Strickland...an his team got it right with his stock panels setup...
All just one mans finding....
P.S.....But like all things in higher end Audio....if you dont go you wont know...
But after all the years of moding Acoustat....I have No Regrets!
You mean like these? They are 'Monitor 3' since I run them with the Acoustat direct drive OTLs. I also have Model 3 with MK-121-2 Medallion interfaces. Virtually Identical but these with the OTLs are in a different league. No comparison imo. The King is alive and well.
Attachments
Last edited:
Mylar dose not work like that when heated....well not on 7-8" wide any way.....but go for it...I have 30extra Acoustat panels ...if you or anyone needs any..good luck..
No like these....Acoustat 3s thay were last made...Andy can say for sure
Lot fun for sure.........
No like these....Acoustat 3s thay were last made...Andy can say for sure
Lot fun for sure.........
Attachments
![00M0M_fcshSeZ0TTm_1200x900[1].jpg](/community/data/attachments/555/555797-112b6f091f517b29b1e5e202b46c3e2b.jpg)
![00p0p_4OfseLLo259_600x450[1].jpg](/community/data/attachments/555/555798-c01a9c2aa2f59c01bcae9b2a697d162d.jpg)
I think you are misunderstanding my post. The panels do not have coating for the first 1/2". The coating itself is not elastic. Attempting to tension the coated area makes no sense. It could only cause the coating to de-laminate similar to painting a balloon and then further inflating it when the paint dries, but in reverse. In any case I have no interest in doing this as mine are functioning as they should.