andy said:
Angelo said:
[SNIP]
The audio performance is entirey due to the expansion of the gas being
heated by the quantity of current flowing through it (I^2*R heating). On
an audio wave peak, the temperature and volume are greatest; on an audio
wave valley, the tempreature and volume are least. I think it is really
a clumsy way of productings ound, inherently nonlinear for moderate to
loud sound levels.
I am not sure I should be posting on this thread but just a couple of
points that may be of interest.
Plasmas in air have two mechanisms for directly producing sound. The
first is a monopole caused by expanding/contracting due to a varying
temperature and the second is a dipole caused by varying the stream of
charged particles rapidly moving between the electrodes and
transferring some of their momentum to the particles of air.
I wonder if a plasma loudspeaker could use a mechanism similar to a
stun gun. The spark from a stun gun does not produce any perceptible
heat in close proximity because -- despite being a 100,000 volts -- the
power is not enough to raise temperature sufficiently to burn the skin.
That being said, the stun gun does make sound when it sparks. I assume
that an equipment similar to the stun gun could be engineered so that
it could produce sparks that would cause the intended sound [e.g.
speech or music].
Conventional plasma speakers produce sparks that reach as high as 2,000
Celsius.
If an high-voltage, low-amperage electric current of 1,000 Hz frequency
is passed through air, a 1,000 Hz tone will result.
.