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Old 22nd March 2017, 09:00 PM   #1701
Discopete is offline Discopete  Canada
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Originally Posted by Jrimer View Post
It also occurs while seated. I posted the question here because many people say the Acoustats roll off at the top quite drastically above 14-15khz. My question is whether some high frequency information exists that is somehow obscured by certain room resonances or canceled out, and for whatever reason, tilting my head forward alleviates this phenomenon. Personally, I think it is room related. It is a huge space- 25' wide x 60' long x 30' tall. The front walls are very "live" as they are mostly glass. Lots of furniture, but also lots of open wall space. Floor is hardwood with oriental rugs covering most of the wood.
Your ears do have an influence on FR just because of how they are shaped.
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Old 22nd March 2017, 09:24 PM   #1702
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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. ��
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Old 23rd March 2017, 04:13 PM   #1703
AcoustatAnswerMan is offline AcoustatAnswerMan  United States
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Originally Posted by Jrimer View Post
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.
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Old 24th March 2017, 03:53 AM   #1704
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I'm not aware of any modifications or rewiring of the speakers.
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Old 4th April 2017, 06:22 PM   #1705
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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.
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Old 4th April 2017, 08:44 PM   #1706
Discopete is offline Discopete  Canada
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Originally Posted by Jrimer View Post
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
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Old 5th April 2017, 01:32 AM   #1707
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So the panels are screwed directly to the wood? What happens when the wood expands and contracts due to temperature and/or humidity? Doesn't that stress the panels and potentially impact the sound?
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Old 5th April 2017, 10:42 AM   #1708
Discopete is offline Discopete  Canada
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So the panels are screwed directly to the wood? What happens when the wood expands and contracts due to temperature and/or humidity? Doesn't that stress the panels and potentially impact the sound?
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.
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Old 5th April 2017, 10:59 AM   #1709
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Is there a link to the hair dryer instructions? I've looked, but can't find a step by step guide to this. Are the grille cloths removed or can it be done with them intact?
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Old 5th April 2017, 08:02 PM   #1710
Discopete is offline Discopete  Canada
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Is there a link to the hair dryer instructions? I've looked, but can't find a step by step guide to this. Are the grille cloths removed or can it be done with them intact?
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.
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