Air Speaker
A website devoted to massless loudspeakers  

plasma speaker chain



Plasma Headphones

Never one to be put off by minor issues like things not working I stepped back from the plasma design and reassessed.  There was one solution that may cure all of the major issues or volume, frequency response, power consumption and toxic gas.  I reduced the project down to headphone size.

Plasma Headphone AmplifierUsing everything learnt so far I reduced the supplies, amplifiers and speaker sizes eventually ending with a twin 4kV 100W supply and 2kV amplifiers.  All of this mounted neatly in a single 19" rack mount case.  For the first time ever I had a stereo plasma system which could be simply switched on and it worked.

Plasma CellWith the size reductions the gap of a single plasma was much reduced and I didn't need manual starting.  The amount of gas produced could be easily adsorbed by activated carbon.  I initially created a plasma cell from ceramic using screws and bolts as electrodes.  These were mounted in a metal (grounded!) headphone assembly with metal grill shields.



Although it worked the volume and frequency response was still not there.  So I further reduced the size of the headphone system until I could fit it to an ear bud.  The electrodes were mounted in a quartz cell.  This meant that all of the sound was directed into the ear and only a small amount of air needed to be driven.  This boosted the volume and frequency response - finally the plasma had the properties of normal headphones, but with the bonus of the perfect sound reproduction of plasma.

Plasma HeadphonesThe toxic gas produced was gently sucked down a silicone tube and out into an activated carbon reservoir.  Being a very tiny amount it was easily dealt with.  The headphones themselves were fairly unwieldy but just about wearable (and made you look like a Cyberman!).

Plasma HeadphoneSome people seem to think that having 4000V either side of your head is a little dangerous.  To be honest I felt safer with these than with many of the previous creations.

To the right is the view down the headphone hole - a tiny stable plasma.






The headphones work well and the whole project is nearly there.  I have one major issue which is the electrode material - I need something that is both quiet and supports a steady arc without wearing too quickly.  Once that is sorted another round of miniaturising and tidying and I should have a very presentable prototype.