Have you ever put anything that has static charge next to a stream of water? Yes - The water bends.
How about doing a electrostatic speaker that has a ultra thin soap bubble as a diaphragm? It should work ok and has extreme high efficiency.
My idea how to test this is to build a plate that has many small holes. It forms a waterfall kind of plate where soaped water or similar is falling slowly down and thousand pieces of water films are formed in holes. These soap films stay because new liquid is fed all the time.
The plate can be a metal grid that has high voltage and it is between stators. Should work, eh. Even curved planars are possible to be build this way.
How about doing a electrostatic speaker that has a ultra thin soap bubble as a diaphragm? It should work ok and has extreme high efficiency.
My idea how to test this is to build a plate that has many small holes. It forms a waterfall kind of plate where soaped water or similar is falling slowly down and thousand pieces of water films are formed in holes. These soap films stay because new liquid is fed all the time.
The plate can be a metal grid that has high voltage and it is between stators. Should work, eh. Even curved planars are possible to be build this way.
THAT is an interesting idea!
I can foresee all sports of problems, but that's what will make it fun to build!
A little glycerin or detergent in the water will make it slightly conductive.
Maybe the center of the speaker will be a perforated panel with the water/soap supply flowing down over it. The small bubbles in the perforations will produce the sound. So you'll have an array of thousands of tiny bubbles (Don Ho?) making the sound. The self resonance should be very high frequency. The only tension on the bubbles will be the surface tension of the liquid. Since you're operating below resonance the response should be very predictable.
I suspect it might be difficult to get the water to flow and form each bubble. You might need something to wipe the bubble-frame periodically to replace popped bubbles.
Definitely an interesting project!
I_F
I can foresee all sports of problems, but that's what will make it fun to build!
A little glycerin or detergent in the water will make it slightly conductive.
Maybe the center of the speaker will be a perforated panel with the water/soap supply flowing down over it. The small bubbles in the perforations will produce the sound. So you'll have an array of thousands of tiny bubbles (Don Ho?) making the sound. The self resonance should be very high frequency. The only tension on the bubbles will be the surface tension of the liquid. Since you're operating below resonance the response should be very predictable.
I suspect it might be difficult to get the water to flow and form each bubble. You might need something to wipe the bubble-frame periodically to replace popped bubbles.
Definitely an interesting project!
I_F
Yes. You propably need some kind of wipening mechanism to constantly build new soap films since you cannot trust that they stay forever. It is possible if you have a motor moving perforated panel slowly against something etc. Silent? Challenge.
It would be good if water drops in the perforated panel could automaticly build and keep thin film in every single hole but that might be hard. We don´t want a thick noisy waterfall over holes spoiling efficiency!
So what to do? Any ideas?
P.S. Soap film can be far below 1um. Good efficiency. No need for audio transformer?
It would be good if water drops in the perforated panel could automaticly build and keep thin film in every single hole but that might be hard. We don´t want a thick noisy waterfall over holes spoiling efficiency!
So what to do? Any ideas?
P.S. Soap film can be far below 1um. Good efficiency. No need for audio transformer?
Fascinating idea. I might just have to try it one of these days (when I have finished my current revision of my stereo).
If you have a vertical disc of perforated material, with only the top of it between the stators, you could rotate it through a 'bath' of water. You will end up with a huge box though, and you have to insulate everything very well. You can alter how much water is left in the holes by varying the position of the stators (towards/away from the bath).
The only problem that I can see with this is that the disc will be unsupported around the edge, possibly causing it to flex.
James
If you have a vertical disc of perforated material, with only the top of it between the stators, you could rotate it through a 'bath' of water. You will end up with a huge box though, and you have to insulate everything very well. You can alter how much water is left in the holes by varying the position of the stators (towards/away from the bath).
The only problem that I can see with this is that the disc will be unsupported around the edge, possibly causing it to flex.
James
I thought different ways of building soap bubbles that last long enough.
One of the easiest way (in theory) would be a a kind of wide "bicycle chain" that rotates slowly. Lower roller is inside a soap water pool and upper in the air. When a chain rise from the pool soap films are formed between each horizontal rod in the chain. No need for a water pump.
The chain goes up between stators and down behind them.
Horizontal rods are made of metal and wide enough for the whole panel. Unfortunately you cannot make curved panel this way.
One of the easiest way (in theory) would be a a kind of wide "bicycle chain" that rotates slowly. Lower roller is inside a soap water pool and upper in the air. When a chain rise from the pool soap films are formed between each horizontal rod in the chain. No need for a water pump.
The chain goes up between stators and down behind them.
Horizontal rods are made of metal and wide enough for the whole panel. Unfortunately you cannot make curved panel this way.
valveitude said:
Hold that right between stators 1-2 mm apart without any change to touch them even if someone walks by or open the window. Add some kilovolts bias and ionize everything around it. Sounds as instabile as plasma in ITER!
There is one more problem. Water is very good breeding ground for microbes. First you must make the liquid denatured, maybe use even a UV-lamp. And somehow be able to wash stators time to time inside if bubbles pops and wet them.
Still... Liquid speaker would be great!
OK, this "whacky" idea has really got me thinkin'
Wouldn't it be possible to replace the crosslinks in the bubble "chain" with serations (spl?) on the upright(s)? The irregular surface should grab the solution, and pull it up. A soap bubble Jacobs Ladder if you will. If this worked, it would simplify the mechanics significantly. Basically two serated wires slowly spinning in a continual loop.
-Casey
Edit:Spelling
Wouldn't it be possible to replace the crosslinks in the bubble "chain" with serations (spl?) on the upright(s)? The irregular surface should grab the solution, and pull it up. A soap bubble Jacobs Ladder if you will. If this worked, it would simplify the mechanics significantly. Basically two serated wires slowly spinning in a continual loop.
-Casey
Edit:Spelling
Discussed with ESL gurus and this idea won´t propably work
Stators attract a bubble because they have different potential. If the bubble is not exactly in the middle the closer stator suck it immediately. That´s because the bubble doesn´t have enough tensile strength.
So what to do? Design a system that only push a bubble from each side? Er...
Stators attract a bubble because they have different potential. If the bubble is not exactly in the middle the closer stator suck it immediately. That´s because the bubble doesn´t have enough tensile strength.
So what to do? Design a system that only push a bubble from each side? Er...
APi said:Discussed with ESL gurus and this idea won´t propably work
Stators attract a bubble because they have different potential. If the bubble is not exactly in the middle the closer stator suck it immediately. That´s because the bubble doesn´t have enough tensile strength.
So what to do? Design a system that only push a bubble from each side? Er...
So, the gurus "popped your bubble"???
Bubble film speaker
hmmnn... there is an electrical contribution to surface tension.. i.e., if you inject electrons into a liquid, the surface tension changes...
maybe a suitable setup to modulate the surface tension of a liquid surface via polarizing opposing stators... hmmnn.. have to give this some more thought...
http://en.wikipedia.org/wiki/Electrowetting
http://www.ececs.uc.edu/devices/NDL_Research.html
one can envision a "dancing droplets" speaker.. or some such
John L.
hmmnn... there is an electrical contribution to surface tension.. i.e., if you inject electrons into a liquid, the surface tension changes...
maybe a suitable setup to modulate the surface tension of a liquid surface via polarizing opposing stators... hmmnn.. have to give this some more thought...
http://en.wikipedia.org/wiki/Electrowetting
http://www.ececs.uc.edu/devices/NDL_Research.html
one can envision a "dancing droplets" speaker.. or some such
John L.
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