Well i could not let go of the stacked idea.
Biggest shortcomings last time where,i needed smaller hole sizes, and more open area.
In this test i did just that.
i used some wicked conductive fabric. 132 threads per inch o.o9 mm thick
open area around 50%.
for this test i used a simple design first to see if the wire mesh is able to be stretched and glued to form a stator. since mesh is not very rigid. spacer distance is 0.5 mm.
This is just a test not sigmented or anything. and membrane stability is an issue off course so HV will be lowish, i intend this structure to be only used for high frequency's. i will make a smaller panel for use from 5000khz up to 20 khz. to get better dispersion, and better membrane stability. i will stack it maximum to be able to lower HV and stepup ratio.
since membrane to membrane distance decreased to 1mm and the stator itself does not contribute much to the distance i can stack more then with the previous types.
i am in nowhere near finishing a good version just experimenting with different materials . but heres a little sneakpeak.
the one playing here is a 3 stacked version
https://youtu.be/YE4Vg3DV6ao
Biggest shortcomings last time where,i needed smaller hole sizes, and more open area.
In this test i did just that.
i used some wicked conductive fabric. 132 threads per inch o.o9 mm thick
open area around 50%.
for this test i used a simple design first to see if the wire mesh is able to be stretched and glued to form a stator. since mesh is not very rigid. spacer distance is 0.5 mm.
This is just a test not sigmented or anything. and membrane stability is an issue off course so HV will be lowish, i intend this structure to be only used for high frequency's. i will make a smaller panel for use from 5000khz up to 20 khz. to get better dispersion, and better membrane stability. i will stack it maximum to be able to lower HV and stepup ratio.
since membrane to membrane distance decreased to 1mm and the stator itself does not contribute much to the distance i can stack more then with the previous types.
i am in nowhere near finishing a good version just experimenting with different materials . but heres a little sneakpeak.
the one playing here is a 3 stacked version
https://youtu.be/YE4Vg3DV6ao
Attachments
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Well im on my own i see
ok i made some measurements for comparison
dont look at the low end since i changed my crossover frequency for the last measurement. its all about the high end.
the weird roll off.
this picture tells us its the membrane thickness in a stacked esl that makes it lose its high frequency range.
for comparison i had
2 stacks of 3Um foil
2 stacks of 6 Um foil
and 4 stacks of 3um foil witch should come close to the 2 x 6um. at least thats was my theory , and it kind of did. so its not the transformer. since 4 stacks has 2 the load of only 2 stacks. still its resembles the 2 stacked 6um.
ok i made some measurements for comparison
dont look at the low end since i changed my crossover frequency for the last measurement. its all about the high end.
the weird roll off.
this picture tells us its the membrane thickness in a stacked esl that makes it lose its high frequency range.
for comparison i had
2 stacks of 3Um foil
2 stacks of 6 Um foil
and 4 stacks of 3um foil witch should come close to the 2 x 6um. at least thats was my theory , and it kind of did. so its not the transformer. since 4 stacks has 2 the load of only 2 stacks. still its resembles the 2 stacked 6um.
Attachments
Ok did a test with spacers. although 0.5 mm stator spacing wil increase sensitivity. t also makes it hard to control membrane collapse. so i tested the same stators but with an exta spacer of 0.5 mm in between. i could up the HV allot. before its starts sizzling. i gain more since i am able to crank up the HV. so there is a golden distance for this size panel at least. where its no longer is usefull to lower spacer distance.
with a membrane distance 2mm appart i could still stack 4 in total for a pretty good gain. i got only 2 stacked right now, so i could gain another 6 db.
there are 2 ways i could go, make the panel that is gone be playing mainly above 4-5khz smaller to increase dispersion, and enable better membrane stability. and thus being able to lower the spacer distance again. and add another stack. or leave it like this and play from 1-2 khz and up with higher HV. but lacking good dispersion. (still better then most panels)
so many ways to go. if i want to incorperate a midrange, it has to be slightly bigger but that screws membrane stability
with a membrane distance 2mm appart i could still stack 4 in total for a pretty good gain. i got only 2 stacked right now, so i could gain another 6 db.
there are 2 ways i could go, make the panel that is gone be playing mainly above 4-5khz smaller to increase dispersion, and enable better membrane stability. and thus being able to lower the spacer distance again. and add another stack. or leave it like this and play from 1-2 khz and up with higher HV. but lacking good dispersion. (still better then most panels)
so many ways to go. if i want to incorperate a midrange, it has to be slightly bigger but that screws membrane stability
What is the width of your panel?
This is what determines the amount of dispersion you will have.
Checkout some of the posts in this thread,
http://www.diyaudio.com/forums/planars-exotics/234975-another-segmented-esl-2.html#post4508004
Also one other thought I had last night is that your Diaphgram to Diaphargam spacing could be what is causing your extreme roll off past 20Khz, not to metion the added mass of the air in between each section.
A 1/4 wavlength distance at 20Khz is just 4.29mm, this would cause a 90 degree difference as the wave is traveling and could be the cause for a drop in the level.
jer
This is what determines the amount of dispersion you will have.
Checkout some of the posts in this thread,
http://www.diyaudio.com/forums/planars-exotics/234975-another-segmented-esl-2.html#post4508004
Also one other thought I had last night is that your Diaphgram to Diaphargam spacing could be what is causing your extreme roll off past 20Khz, not to metion the added mass of the air in between each section.
A 1/4 wavlength distance at 20Khz is just 4.29mm, this would cause a 90 degree difference as the wave is traveling and could be the cause for a drop in the level.
jer
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What is the width of your panel?
This is what determines the amount of dispersion you will have.
Checkout some of the posts in this thread,
http://www.diyaudio.com/forums/planars-exotics/234975-another-segmented-esl-2.html#post4508004
Also one other thought I had last night is that your Diaphgram to Diaphargam spacing could be what is causing your extreme roll off past 20Khz, not to metion the added mass of the air in between each section.
A 1/4 wavlength distance at 20Khz is just 4.29mm, this would cause a 90 degree difference as the wave is traveling and could be the cause for a drop in the level.
jer
Thc gerald
We had discussed this isue and up to 4 stacls of 2mm membrane to membrane is possible with a loss of around 3 db at 20khz. and yeah the dispersion is dictated by the width(horzintal a t least) thats why my first model was sigmented. but i can see the confusion and its kind of my fault. i opened a new thread and should have added this to the http://www.diyaudio.com/forums/plan...ndwich-esl-yummie.html?highlight=sandwich+esl
I will try to copy it over there and continue over there since its getting messy like this. sorry guys my fault!
could an admin help me out maybe ?
Thread continues over here
http://www.diyaudio.com/forums/planars-exotics/272742-sandwich-esl-yummie-11.html
Sorry
http://www.diyaudio.com/forums/planars-exotics/272742-sandwich-esl-yummie-11.html
Sorry
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