Questions with ESL

[Packers]

Hello.

Recently I got interested in ESL Speakers after hearing them online. However to build one, a thousand volts and up are required. Also you need two currents going to the completed sandwich, an AC to the Stators and a DC current to the membrane.

Out of curiosity and my small financials status, I was curios if it was possible to build a ESL speaker on a smaller scale with less volts. Is there a math formula to determine how many volts are required to polarize the Stators.

Also, does the DC Voltage have to match the AC voltage? Videos online ( that I have seen, I have not seen every video yet ) only give the amount of AC voltage applied and not the DC. The EHT boards that I have seen that proved the power to the membrane are ridiculously high. So instead, I was thinking of taking the voltage from the transformer and giving it to a Bridge Rectifier ( Some are as cheap as $1, the ones that are that cheap probably wont work tho, but it would still be cheaper then an EHT board ) which would convert the AC to DC and thus power the membrane. Would this work? In theory I would assume, but I have not seen any one else do this.

Thanks in advance for providing insight.

 

[owenhamburg]

Out of curiosity and my small financials status, I was curios if it was possible to build a ESL speaker on a smaller scale with less volts. Is there a math formula to determine how many volts are required to polarize the Strators.

The voltage you want is such that it is less than the breakdown of air across the stator gap.

An electric field strength of about 3 x 106 V/m or 3 kV/mm.

So with a 1mm gap for a deflected stator, the PP voltage cant be more than 3kV between the DC on the membrane and the AC on the stator.

Also, does the DC Voltage have to match the AC voltage?

No. But its not a bad idea to think in that sort of range.

Videos online ( that I have seen, I have not seen every video yet ) only give the amount of AC voltage applied and not the DC. The EHT boards that I have seen that proved the power to the membrane are ridiculously high.

No the power to the membrane is very low.

All that is required is to not leak the voltage, Electret speakers and microphones, typically take no power.
The QUAD ESL-2812 and ESL-2912 consume only 6W.

So instead, I was thinking of taking the voltage from the transformer and giving it to a Bridge Rectifier ( Some are as cheap as $1, the ones that are that cheap probably wont work tho, but it would still be cheaper then an EHT board ) which would convert the AC to DC and thus power the membrane. Would this work?

Yes, it has been done before, with electrostatic headphones from KOSS but in my opinion is not worth it.

In theory I would assume, but I have not seen any one else do this.

Thanks in advance for providing insight.

Your main cost will be the transformer to make the high voltage AC on the stators.

You can make a good ESL tweeter, for around 200 Euros, the speaker costing less than 10 Euro (couple of PCB's and some mylar some polystyrene sheet to make spacers, and some copper tape) , and the rest being the cost of transformers (to take the amplifier voltage output to stator voltage), tools, and high voltage supply in decreasing order of cost.

 

[Packers]

So it would be PCB, Spacer, Mylar, Spacer, PCB. Why leave out the copper charge ring and have the DC go straight to the Mylar?

This looks way easier then creating a planar speaker.

 

[WrineX]

So it would be PCB, Spacer, Mylar, Spacer, PCB. Why leave out the copper charge ring and have the DC go straight to the Mylar?

This looks way easier then creating a planar speaker.

the basics are really easy indeed. a planar might still be a better choice if your new to it all. i did a pretty bunch of ESL's and while the setup is easy, i encountered enough problems evey now and then to think about using planars 🙂. a planar is pretty obvious and when you got it working it will stay working until you burn them.