high efficiency easy to drive esl

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Always thought my mocode, acoustat 2+2/vandersteen sub... soundedfantastic. Then I made Georges fine single ended triode. What an amp!
I'm wondering if it is possible to make an esl that is at least 93 dB efficient.
I know there are trade offs, and I would be willing to do open baffle bass below ~300Hz.
Some (probably bad) ideas I've had are to have two esl drivers with two tranformers separated with a crossover.
The tweeter module would be about 4" wide, and have a very thin stator to diaphram spacing ~.75mm.
The midrange module would be about 10"wide 1.0mm spacing.
I like the idea of acoustat style cube louver support., and could make it with one panel 4ft tall, or two panels 8ft tall
I won't bother trying, if it isn't possible to make a very efficient esl
My tubelab amp cry's when I hook it up to my acoustats, but sings great when hooked up to some open baffles.
Thanks,
Paul
 
Yes, it is possible, but not easy I think.

* I would suggest a very long, narrow tweeter in a baffle about 5 times the width of the element.
* Try for a very high diaphragm polarization voltage; this will require a very clean construction to avoid HV leakage.
* Use bi-amping and if you need equalization, make it active (before the amp, not after).
* I'm not sure you would really need 2 separate ESL panels for mid and high.

Kenneth
 
Hi,

it´be possible with a hybrid design, but not with a Fullranger.
Still though I suggest at least clean and stable 20W for such a panel.
The problem is that You are limited in several aspects.
First with the level of polarizing voltage. 1.5kV/mm is usually fine, 1.7kV/mm might already give problems under certain atmospheric conditions or lower build quality and 2kV/mm will certainly lead to flashovers.
The second are the large area and small stator-stator distances required for increased efficiency and high SPLs. This leads to high capacitance values which are transformed up quadratically by the audio transformer. So the amp faces a large capacitance as load. A state of affairs most amps are not designed for and with which many can´t cope with.
The third beeing the difficult complex load the amp will see. Depending on the transformer quality the complex power wasted within the amps Power Supply and its Output devices will be several times larger than the real power that´s used to generate sound. The amp will have to supply for more wattage than it can actually deliver to the speaker...up to 10times more! The weird thing is, that a good Transformer worsens the matters for the amp, because the amp ´sees´ more of the speaker´s capacitance and less of the transformer´s losses.

jauu
Calvin
 
So very true ,Clavin,so very true.
I have gotten much better at my typing and appericiate your input on my transformer design if you are willing.
I'm currently working on a system with those dimension.it is not easy getting a proper drive but i have my 3.5"x9.5" sounding pretty good so far. jer
 
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