|29th March 2013, 09:29 PM||#21|
Join Date: Feb 2008
I used aluminium wire mesh that was double powder coated for my panel.
Then about seven years later when I refurbished them I sprayed them with some clear acrylic to real seal them.
They worked very very well although ithey took at least 5.5KV of bias and as mush as 1:256 step-up ratio to get a high output out of them.
They will work just fine on a 1:128 ratio as well with a drop of 6 db in efficiency.
In their Grandest state they produced well over 105db at a 1 meter distance using test tones down to about 250Hz to 300Hz.
Due to the high step-up ratio, and, the transformers capacitance being 8 times more than the panel itself, this presents a load well below about 1 ohm to .5 ohm at 20Khz.
This didn't cause to much of an issue using my low power cheapy AWIA amplifier at reasonable listening levels of about 100db at 2 feet away.
This was about the limit to what the little 5.25" woofer could do anyhow.
I found that to takes about 2 to 3 times the surface area of my little panel to match the efficiency to that of your typical woofer using about a 1:120 step-up ratio.
The Diaphragm size of the panels is 3.25" X 9.75"
I have ran this panel experimentally up to 10KV of bias and 25KVp-p across the stators before several times until it had met its finally demise......Fire!!
I did it just to find its absolute limits to improve upon it in the next build.
The screens where glued on to the egg crate using super glue after they were coated.
The sharp edges of the wire were buried in some clear GE silicone rubber with the inside edges of the diaphragm frame overlapping about 1/16" to 1/8" for added protection.
There was one spot that was not buried deep enough and this was the weak point that ultimately caused the panels to fail after 7 years.
An easy fix in the next build.
I was able to fix the panel and use it for 3 more years but all other attempts to reach the voltages I once did resulted in more leaks and Fire's.
Under normal conditions this never occurred, at all!!
Thus I decided to build new panels.
I will be building another one just like it soon using some improved techniques I have learned from the last one.
I have found that I can get as much as 15KV of insulating qualities for the stator coating using a proper painting method with common off of the shelf Spray paint.
With a coating thickness of just 8mil to 10mil.
This will be the basis of my second new build to replace the old ones that finally gave out.
That is how much I liked them as they were.
Very worth building a new pair.
Did I mention very inexpensive to do?!!!!
The original panels had a frequency response that was ruler flat in the nearfield.
As all ESL's will exhibit this in the nearfield as was there intended use.
Many times I had listened to them at a lowered level in a full range mode without a woofer and the sound quality was jaw dropping.
This is a great alternative for those whom don't have the funds to make or the space to have larger panels!!!
I like the smaller panels mainly because of their size as they are easier to move around and aren't as cumbersome.
They also don't have anything near as bad of the beaming issues that larger panels have, if at all!
Most complain about not having enough bass, But that is what woofer's are for.
They will get very loud if made properly to handle the voltages required to get there!!
Larger panels do have an advantage in this perspective due to their large surface area.
This is not an issue when listening to them in the nearfield anyhow.
And the cost of building them is so much more cheaper than the perforated metal technique.
However the technique you choose to build them you will definitely yield a much better sounding product than you will get with the common box speaker.
As usual they do have a few short comings about them, But, If you can live with those and overcome the obvious ones then you won't be sorry in the long run once you hear them powered up for the first time!!!
Last edited by geraldfryjr; 29th March 2013 at 09:39 PM.
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