Plasma Tweeter Modulation Issues
Weston, Wed Sept 24 2014, 08:19PMFor the past few months I have been working on a 6.78MHz plasma tweeter and have been having some issues trying to increase the volume.
The system is a push pull class E tesla coil and a class D modulator. Modulation depth is used to control volume. I should also be able to control volume by changing the idle power driving the resonator. However, from my observations, the discharge size seems to have little effect on volume. I get almost the same volume with with only 50 watts creating a very small discharge or with 300 watts creating a 1" jet of plasma. At full modulation and full power, the system is almost as loud as my laptop.
I was under the impression that plasma could be modulated very fast, but it seems that the majority of the plasma I am creating is not contributing to the audio volume. Has anyone encountered this before with plasma tweeters?
Re: Plasma Tweeter Modulation Issues
..., Wed Sept 24 2014, 10:32PM
Likely you are just running into the logarithmic response of a human ear.
Also, it is possible that at higher frequencies there is more background noise (in particular, if the plasma is going from a stable blob to unstable flame) and thus drowning out the audio.
Do you have a way to measure the volume using a microphone of some sort? It would be interesting to see how the sound pressure varies with input power.
..., Wed Sept 24 2014, 10:32PM
Likely you are just running into the logarithmic response of a human ear.
Also, it is possible that at higher frequencies there is more background noise (in particular, if the plasma is going from a stable blob to unstable flame) and thus drowning out the audio.
Do you have a way to measure the volume using a microphone of some sort? It would be interesting to see how the sound pressure varies with input power.
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