Some ESL questions

[bacon665]

So ive been thinking of alternate way to make an ESL besides using a center tap transformer and ive run into several problems/questions
so here goes.

For the following questions assume that the signal is being applied to the diaphram not the stators.

1) To apply current to the stators would you still need two stators since the diaphram would both attract and repel from the plate.

2) how would you generate negative 5000 DC ?

3) some other guy here put magnets on his electrostats...
I dont know what they where for in his design but is it possible to use strong magnets on the stators (one side south other north) then apply the signal to the diaphram and bypass th need for a polarizing HVT?

[Calvin]

Hi,

A1) No, if You apply the signal to the diaphragm, the diaphragm needs a highly conductive coating. So You would build a classical asymmetric style ESL, the oldest incarnation of an ESL. You´d need a polarizing voltage and a lot of mechanical tension. The tension counters the attracting force stemming from the polarizing voltage and the membrane will position itself at a ´no-signal reference point´ (or Bias-Offset) somewhere between the points "position of the stretched membrane without polarizing voltage" and "contact to the stator" (ideally halfway).
Since the electrical field strength varies quadratically with the distance of stator and membrane the driving forces are not linear and so distortions are high (they can be kept reasonably small only for very small strokes). Additionally the efficiency would be much lower than with a symmetrical ESL. Further more, highly conductive coatings are less safe. In case of a flashover -which nearly can´t be avoided with ESLs anyway- it burns at least a hole in the membrane or at worst the whole membrane burns down. Since the building size of a symmetrical and a asymmetrical ESL are nearly the same and because basically every parameter improves with a symmetrical ESL its the way most modern ESLs are built.

A2) with a HV-supply. There are lots of circuits around from simple HV-cascades to elaborated regulated supplies

A3) I don´t know either. Maybe the ESL panel was too lightweighted to be considered as proper HighEnd. It definitely doesn´t renders the HV-supply obsolete.

jauu
Calvin

[bacon665]

Thanks Guess ill be doing it just like everyone else then...

[bacon665]

Anyone ever used Wire mesh instead of magnetwire/steel sheets?

[Few]

Metal mesh and screen have been used. You might look up old SpeakerBuilder magazines--I believe there was an article on the use of window screen.

One problem you're likely to encounter is that the wires don't all lie in the same plane as a result of being woven together. You therefore end up with "hot spots" where the wires in one stator lie close to the other stator and the electric field strength is high, and "cold spots" where the stator to stator is distance is greater and the electric field is lower. The hot spots limit how high you can set the bias voltage, and the cold spots reduce the sensitivity of the speaker. It's better to have truly uniform spacing between the two stators.

Few

[bacon665]

what about iron slats i think you can get them at lowes in 6 foot by 1 inch by 2mmi looked into the magnet wire but alot of people splice them in the center and hook them too....
curtain rods?
http://members.home.nl/p.vanassouw/

lol and it seems cheesy to me
then again they do look rather nice...