A tuning system had crossed my mind on occasion while I while as was reassembling my little panels.
One time I had over tensioned the diaphragm and the resonate frequency of it got much higher into the 120hz to 150hz range as typically I get in the 70hz to 90hz consistently.
I was trying to see if there was a change in performance for different tensions and I found that there is no change performance and only a change in the resonance in the resonance of the diaphragm is what occurs.
So I simply loosened the sandwiching bolts and squeezed the sides of the frames together,re-tightened the bolts and I was good to go.
I normally run them above this resonant frequency so it is not much an issue.
Using a mechanical stretching technique can help you to get a consistent customizable tension.
Especially on a large panels and ones that are made to be open and run full range.
CharlieM uses this method on his panels and it works very good I just haven't made a stretcher yet.
I guess from what I have read, Quad had used both methods of first mechanically stretching them and then into a controlled heat oven.
I don't have any experience with the ML's except that I had heard a set of the Aerius a few weeks before I had finished my very first usable pair with a 7.75" X 22.25" diaphragm size.
And my first impression was that even with my own crude little setup they were IMHO a notch above of the ML's and the Apogee Duette's that I have enjoyed for many years.
I thought that ML was insane for the price they charge for a set of them brand new and I have never turned back.
Although I do admit I have been tempted to get a used pair on occasion when the price was right.
Then I built my smaller panels and I was even more impressed as due to its smaller width they were not as directional and I didn't have to sit with my head in a vise.
They were also designed to run with a much higher bias voltage and this compensated for the drop in efficiency of being 1/4 of surface area of my bigger panels.
I get about 88db to 90db as well at one meter with a 4v to 5v peak (1 watt) into a 1:250 transformation ratio and a 7kv bias with my little panels of 3.25" X 9.75" and a D/S of approximately .072" to .075".
I am sure that a larger panel can get much higher than this because of a greater surface area.
Sadly those panels have met there demise and had served me well for 9 years as they weren't design to meet the voltages I was giving (testing) them at 25kv p-p across the stator's.
My new ones will be able to handle such voltages and they have just surpassed an arc test at 13.61kv with no gap and no arc through.
I am just waiting on the stataor coating to cure and harden up some more so that I can add the diaphragm.
Otherwise they will stick to the frames and this will destroy the coating when I try to take them apart to change out different thickness of spacers and diaphragms to try.
This has already happened and I had to repair a few spots twice already.
jer
One time I had over tensioned the diaphragm and the resonate frequency of it got much higher into the 120hz to 150hz range as typically I get in the 70hz to 90hz consistently.
I was trying to see if there was a change in performance for different tensions and I found that there is no change performance and only a change in the resonance in the resonance of the diaphragm is what occurs.
So I simply loosened the sandwiching bolts and squeezed the sides of the frames together,re-tightened the bolts and I was good to go.
I normally run them above this resonant frequency so it is not much an issue.
Using a mechanical stretching technique can help you to get a consistent customizable tension.
Especially on a large panels and ones that are made to be open and run full range.
CharlieM uses this method on his panels and it works very good I just haven't made a stretcher yet.
I guess from what I have read, Quad had used both methods of first mechanically stretching them and then into a controlled heat oven.
I don't have any experience with the ML's except that I had heard a set of the Aerius a few weeks before I had finished my very first usable pair with a 7.75" X 22.25" diaphragm size.
And my first impression was that even with my own crude little setup they were IMHO a notch above of the ML's and the Apogee Duette's that I have enjoyed for many years.
I thought that ML was insane for the price they charge for a set of them brand new and I have never turned back.
Although I do admit I have been tempted to get a used pair on occasion when the price was right.
Then I built my smaller panels and I was even more impressed as due to its smaller width they were not as directional and I didn't have to sit with my head in a vise.
They were also designed to run with a much higher bias voltage and this compensated for the drop in efficiency of being 1/4 of surface area of my bigger panels.
I get about 88db to 90db as well at one meter with a 4v to 5v peak (1 watt) into a 1:250 transformation ratio and a 7kv bias with my little panels of 3.25" X 9.75" and a D/S of approximately .072" to .075".
I am sure that a larger panel can get much higher than this because of a greater surface area.
Sadly those panels have met there demise and had served me well for 9 years as they weren't design to meet the voltages I was giving (testing) them at 25kv p-p across the stator's.
My new ones will be able to handle such voltages and they have just surpassed an arc test at 13.61kv with no gap and no arc through.
I am just waiting on the stataor coating to cure and harden up some more so that I can add the diaphragm.
Otherwise they will stick to the frames and this will destroy the coating when I try to take them apart to change out different thickness of spacers and diaphragms to try.
This has already happened and I had to repair a few spots twice already.
jer
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To bad about the ML panels...as much fun for years that i have had i would never tell any one to buy there new ESL speakers .....less thay can sale are give the speakers away in 2-3 years...by this time the panels have lost 20-30% of there out put...
ML dose not wont to make panels any more thats why the CLs panels now cost $2500 for a new pr...
But one way i have been geting the biger panels to give better ouput ones you can get the panels apart like the 12-16w"x46-48"h.... is to run Bias feed foil... On the frount cross stader...an up an down the two sides....then when you put the panels back togather...
It make better contack an give more bias...all over the panels........ i like the Alum tape type... to me has better topend...the copper turns green an lose output on it own......have fun...hohoho
ML dose not wont to make panels any more thats why the CLs panels now cost $2500 for a new pr...
But one way i have been geting the biger panels to give better ouput ones you can get the panels apart like the 12-16w"x46-48"h.... is to run Bias feed foil... On the frount cross stader...an up an down the two sides....then when you put the panels back togather...
It make better contack an give more bias...all over the panels........ i like the Alum tape type... to me has better topend...the copper turns green an lose output on it own......have fun...hohoho
Never had a ML, Like to get a CLS just to see how their made, I always thought of them as being stacked curved panels, never knew they were a full curved panel. Could you show a side edge view of the panel? . I imagine they would have cross supports on rear side of panel to keep the diaphram tite, or maybe they use the stator as the tensioning device. Al
Frist pic is the CLs back with mylar...all the ML panels are rolled 30% .... ML metel it starts flat...Thay roll the metel only then put on the myar..in the pix
....in the pix you can see thay pull the mylar only from the top to bottem... Then thay do the sides by hand..
Then he rools mylar so it stick good all the.way around the back of the one panel half...puts the front half on...good luck
....in the pix you can see thay pull the mylar only from the top to bottem... Then thay do the sides by hand..
Then he rools mylar so it stick good all the.way around the back of the one panel half...puts the front half on...good luck
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know two... front an back... the mylar an bias feed is only on the back like you see in the other posted pic...
in this pix hes laying out the staters cross bars...see the gred...so he can get the cross bars the same on bouth panels... on the front an back ..then he well put the mylar an bias feed.. on the back only...
in this pix hes laying out the staters cross bars...see the gred...so he can get the cross bars the same on bouth panels... on the front an back ..then he well put the mylar an bias feed.. on the back only...
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![2[1]%20(2)[1].jpg](/community/data/attachments/292/292444-9eb9cd69fdb0b944c6efb28c1214ed5b.jpg)
Do I see this correctly , the cross strips go on the lower stator, then the diaphram? Do the cross strips act as a spacer to keep the daiphram from hitting the lower stator? If so the top stator wouldn/t need any, am I correct here? I/m gonna see if I can find a bad set.
Would this mylar be to thick?
48-1F-OC
.001" thick Optically Clear Mylar®/Polyester Film
36 in
25 Feet
.001
$31.09
like to buy it in 100ft rolls, I got the Licron and double side tape
Would this mylar be to thick?
48-1F-OC
like to buy it in 100ft rolls, I got the Licron and double side tape
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Yes the cross strips act as spacers.
You want to find some .5mil (.0005") or thinner like .25 mil (.00025").
The 1 mil mylar would work especially for a larger width bass panel.
However the thicker stuff seems to take away some the the highend detail a bit.
This is due to its greater mass.
I have used such thickness's before in the forms of model airplane coverings (monokote,Ultrakote,etc.),But IMHO the thinner stuff does sound the best.
Some .25 mil mylar is hard to find but can be had.
Even the thinner stuff can be found as well but generally are only usable for narrow tweeter panels and head phones and such.
I have some as thin as .06mil stuff but I could only find it in 3" widths.
Also the thinner it is the less tension you can put on it for a given width as it stretches more.
Pretty much .25 mil is optimum for your average panel size but .5mil is acceptable and used quite often as it is easier to find.
1 mil could be used to practice construction with.
But, Don't expect any spectacular results in the sound as it may end up having a limited high frequency response and detail.
Which Licron did you get as there are two versions "Licron" or "Licron Cyrstal"?
Either will work but the Cyrstal is the one to use as it is much much thinner and it is nearly transparent.
I have A&B both and only in a side by side comparison could I really notice the difference in the sound but they Cyrstal is better.
A few years ago I had gotten a very good price on a whole roll of 1000 feet or maybe it was 2000 feet of some 4' wide .5 mil for $200 and the plastic company was going cut it in half for me for $100 for a roll.
The .25mil stuff I have is 12.5" wide and I got it back in 1990 as a close out from a company that sold materials to build ultralite aircraft and it is not made in north america any more.
I begged Dupont to start producing it again but I did have a place to put a full 1 or 1/2 ton roll of it 10ft long !!!!
I wish I had now and I wish I had gotten more of what I do have back then, not knowing that it would be so difficult to find and yet sought after as I only paid about $18 with the shipping!!!
Luckily I have plenty for my own projects for now (approx. 250'), But it can be gotten if I need more.
jer
You want to find some .5mil (.0005") or thinner like .25 mil (.00025").
The 1 mil mylar would work especially for a larger width bass panel.
However the thicker stuff seems to take away some the the highend detail a bit.
This is due to its greater mass.
I have used such thickness's before in the forms of model airplane coverings (monokote,Ultrakote,etc.),But IMHO the thinner stuff does sound the best.
Some .25 mil mylar is hard to find but can be had.
Even the thinner stuff can be found as well but generally are only usable for narrow tweeter panels and head phones and such.
I have some as thin as .06mil stuff but I could only find it in 3" widths.
Also the thinner it is the less tension you can put on it for a given width as it stretches more.
Pretty much .25 mil is optimum for your average panel size but .5mil is acceptable and used quite often as it is easier to find.
1 mil could be used to practice construction with.
But, Don't expect any spectacular results in the sound as it may end up having a limited high frequency response and detail.
Which Licron did you get as there are two versions "Licron" or "Licron Cyrstal"?
Either will work but the Cyrstal is the one to use as it is much much thinner and it is nearly transparent.
I have A&B both and only in a side by side comparison could I really notice the difference in the sound but they Cyrstal is better.
A few years ago I had gotten a very good price on a whole roll of 1000 feet or maybe it was 2000 feet of some 4' wide .5 mil for $200 and the plastic company was going cut it in half for me for $100 for a roll.
The .25mil stuff I have is 12.5" wide and I got it back in 1990 as a close out from a company that sold materials to build ultralite aircraft and it is not made in north america any more.
I begged Dupont to start producing it again but I did have a place to put a full 1 or 1/2 ton roll of it 10ft long !!!!
I wish I had now and I wish I had gotten more of what I do have back then, not knowing that it would be so difficult to find and yet sought after as I only paid about $18 with the shipping!!!
Luckily I have plenty for my own projects for now (approx. 250'), But it can be gotten if I need more.
jer
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Cool that's the stuff !!!
These guys have thin Mylar for a reasonable price.
Products
I found it here,
.25 mil mylar - Google Search
jer
These guys have thin Mylar for a reasonable price.
Products
I found it here,
.25 mil mylar - Google Search
jer
FYI- You Don't want to use Metalized Mylar for a ESL.
Use the clear stuff only.
Thanks for the links !!!
FWIW
jer
You're right ger. I didn't catch the metalized part.
But they also have clear. Here's another source:Products
Quote"Hi Jer, I wonder if the film used to cover windows would work, the stuff you heat gun shrink for inside winter use, it's clear as day and is very strong. Al "
This materials is not a suitable choice. You want a C grade Mylar or the equivalent material from an alternate vendor. Mylar is made by DuPont. As it has been explained shrink film provides just enough tension to get the job done. HS 65 Mylar is what your Acoustats uses, it is made by DuPont and is about as good as it gets for quality HS film the stuff you will find in home window insulation kits is not even close.. A proper quality C grade film (capacitor grade) is what you want and is one which will stand high tension. if you can find tensilized film buy it as that is even stronger but is almost impossible to find. In fact I would doubt most vendors who might claim to have tensilized film. A simple stretching frame is all you need but there are a number of good ideas for stretching film in the archives here. I hope this helps. Best regards Moray James.
This materials is not a suitable choice. You want a C grade Mylar or the equivalent material from an alternate vendor. Mylar is made by DuPont. As it has been explained shrink film provides just enough tension to get the job done. HS 65 Mylar is what your Acoustats uses, it is made by DuPont and is about as good as it gets for quality HS film the stuff you will find in home window insulation kits is not even close.. A proper quality C grade film (capacitor grade) is what you want and is one which will stand high tension. if you can find tensilized film buy it as that is even stronger but is almost impossible to find. In fact I would doubt most vendors who might claim to have tensilized film. A simple stretching frame is all you need but there are a number of good ideas for stretching film in the archives here. I hope this helps. Best regards Moray James.
I had gotten some of that window film but never tried it as it was too thick.
Then I had read that the the backing that comes on it that you peel off and discard is what you use and was Mylar.
It may be some kind of PET film but I don't believe that it is mylar.
It seemed to be too soft and stretchy so I never used it.
I still have that very same roll of it 10 years later.
I was looking to build some larger wider panels at the time but I had never built any at all yet.
So that was when I settled on my smaller versions and used what I have as I knew it was the right stuff.
As I mentioned I used model airplane covering's for my very first diaphragms until I had my construction techniques and coating method down pat as not to waste what I do have.
I was using Graphite at the time.
Graphite is a PIA to do and is very hard to get a good consistent coating.
It took a lot of practice to get it right and I wasted a bit of material trying to do so.
Not to mention that it is very messy and it gets on the stator and other piece's where it is not wanted and causes charge leakage issues when it does.
Yes, tensilized mylar is what you want to use as if it isn't then it will keep stretching over time until it finally stops so a mechanical stretcher is a very good thing to have as mechanical stretching is how they tensilize it in the first place.
I have some kapton but it is very expensive and difficult to locate in thin grades as well.
It does not stretch at all like maybe about .5% at most.
Also, It will not shrink using a heat of any temperature unless it starts to burn or melt.
So, A mechanical stretcher is a must and is required for working with this material.
I have fancied the idea of using it for some ESL's designed for the high heat environment of automobiles in the summer time as well as the cold.
Mylar's tension changes in in these extreme types of temperature changes and from what I have read Kapton does not.
Since this is a thread about Diaphragm Coatings, Stator Coatings must not be over looked as well !!!!
This cannot be stressed enough as I have done quite a bit of research on this subject.
I have had to replace more than my share of precious mylar diaphagms due to burn holes because of stator coating failure.
My last panel that had burned up still had it's original mylar and licron diaphragm that I made for it 10 years ago.
Have you given this some thought?
Checkout the my latest pictures of arc testing my new stator's here,
A Segmented Stator Desktop ESL
Although this new panel won't be run at at 13.6kv of bias voltage, the voltages across the stator's will easily reach and exceed these values.
10kv is my goal for 100% stability as I was their before and above this the voltages becomes very very difficult to contain.
It wasn't the High Bias voltage alone that killed the last panel as it was only at about 6.5kv at the time it had burned.
It was the added voltage out of the transformer at about + 25kv p-p on a high frequency peaks across the stators is when the breakdown occurs mostly.
Remember, I had only a .075" D/S.
This is not so much of a problem for larger ESL's as it is for a smaller ones.
This is due to its larger surface area as they rarely need to be driven that hard to reach the same high SPL's.
FWIW
jer
Then I had read that the the backing that comes on it that you peel off and discard is what you use and was Mylar.
It may be some kind of PET film but I don't believe that it is mylar.
It seemed to be too soft and stretchy so I never used it.
I still have that very same roll of it 10 years later.
I was looking to build some larger wider panels at the time but I had never built any at all yet.
So that was when I settled on my smaller versions and used what I have as I knew it was the right stuff.
As I mentioned I used model airplane covering's for my very first diaphragms until I had my construction techniques and coating method down pat as not to waste what I do have.
I was using Graphite at the time.
Graphite is a PIA to do and is very hard to get a good consistent coating.
It took a lot of practice to get it right and I wasted a bit of material trying to do so.
Not to mention that it is very messy and it gets on the stator and other piece's where it is not wanted and causes charge leakage issues when it does.
Yes, tensilized mylar is what you want to use as if it isn't then it will keep stretching over time until it finally stops so a mechanical stretcher is a very good thing to have as mechanical stretching is how they tensilize it in the first place.
I have some kapton but it is very expensive and difficult to locate in thin grades as well.
It does not stretch at all like maybe about .5% at most.
Also, It will not shrink using a heat of any temperature unless it starts to burn or melt.
So, A mechanical stretcher is a must and is required for working with this material.
I have fancied the idea of using it for some ESL's designed for the high heat environment of automobiles in the summer time as well as the cold.
Mylar's tension changes in in these extreme types of temperature changes and from what I have read Kapton does not.
Since this is a thread about Diaphragm Coatings, Stator Coatings must not be over looked as well !!!!
This cannot be stressed enough as I have done quite a bit of research on this subject.
I have had to replace more than my share of precious mylar diaphagms due to burn holes because of stator coating failure.
My last panel that had burned up still had it's original mylar and licron diaphragm that I made for it 10 years ago.
Have you given this some thought?
Checkout the my latest pictures of arc testing my new stator's here,
A Segmented Stator Desktop ESL
Although this new panel won't be run at at 13.6kv of bias voltage, the voltages across the stator's will easily reach and exceed these values.
10kv is my goal for 100% stability as I was their before and above this the voltages becomes very very difficult to contain.
It wasn't the High Bias voltage alone that killed the last panel as it was only at about 6.5kv at the time it had burned.
It was the added voltage out of the transformer at about + 25kv p-p on a high frequency peaks across the stators is when the breakdown occurs mostly.
Remember, I had only a .075" D/S.
This is not so much of a problem for larger ESL's as it is for a smaller ones.
This is due to its larger surface area as they rarely need to be driven that hard to reach the same high SPL's.
FWIW
jer
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So, let's go back to the original topic .
I was curious about the nylon coating quad used in their quad 57 and refurbishing process to more or less similar specs as the original.
There is an "Electrostatic Speaker Conductive Coating Elvamide 120g" on sale in EBay.
However there are different grades of elvamide with different moisture content.
Table below suggests that 8023R/8066 are preferable(0-5%) and 8061/8063(0-0.7%) are not.
Also the datasheet says that 8061 comes in 3 mm cubes(and is the only type which comes in cubes). Since elvamide on e-bay also comes in cubes my conclusion is that they are selling 8061 and this should not be suitable as a coating.
Any experience?
Regards,
Lukas.
.I was curious about the nylon coating quad used in their quad 57 and refurbishing process to more or less similar specs as the original.
There is an "Electrostatic Speaker Conductive Coating Elvamide 120g" on sale in EBay.
However there are different grades of elvamide with different moisture content.
Table below suggests that 8023R/8066 are preferable(0-5%) and 8061/8063(0-0.7%) are not.
Also the datasheet says that 8061 comes in 3 mm cubes(and is the only type which comes in cubes). Since elvamide on e-bay also comes in cubes my conclusion is that they are selling 8061 and this should not be suitable as a coating.
Any experience?
Regards,
Lukas.
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