115 th NYC October 10-13 2003 . Waves and Beams. http://ionAudio.net. The flame has no mass: Perfect Transient Response, Acoustic Impedance Match!. Improve overall system linearity. Increase flame size to include midrange frequencies!!.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Waves and Beams
The flame has no mass: Perfect Transient Response, Acoustic Impedance Match!
Improve overall system linearity
Increase flame size to include midrange frequencies!!
The flame has no directional preference: Omnidirectional Acoustic Point Source!
Try Helium gas for more efficient flame and wider frequency response.
Improve system power efficiency by using a solid state high voltage oscillator
Positive DC Corona
In positive corona, electrons are accelerated toward the electrode.
As noted by S. Klein, high voltage oscillation frequency below 3MHz produces hissing. This phenomenon is a direct result of ion motion.
In negative corona, ions are accelerated toward the electrode and bombard it, causing sputtering and secondary emission of electrons.
Negative DC Corona
Helium, an inert, monoatomic gas, has higher electron velocities than air, leading to higher sound pressure levels.
In AC corona, the heavier ions form a region of space charge, causing much higher electric fields, sustaining corona.
AC CoronaThe Plasma Tweeter
Plasma Science and Fusion Center
Massachusetts Institute of Technology, Cambridge, MA 02139, USA
What is a “Plasma Tweeter?”
Sound is generated by a high voltage corona discharge. An audio signal causes this flame to change size, creating sound waves!
The dome tweeter is too large for its small wavelengths, leading to the “beaming” effect.
Basic circuit operation:
1. Some disturbance causes the current in the Tesla coil to shift quickly, generating a voltage.
2. This voltage is sensed by feedback and causes the 6KG6A tube to direct more current away from the coil. The feedback signal dies.
3. More current flows in the coil, triggering the feedback - An oscillator is born! The high voltage self-sustains a corona discharge.
4. The amount of current deflected by the 6KG6A tube is controlled by an audio signal, altering the flame height quickly.
The Tesla Coil is chosen to have low capacitance, low losses and high Q.
The feedback driven oscillator is necessary because the coil must operate at its self-resonant frequency.
This resonant frequency drifts slightly as the flame size changes, and must be above 3-5MHz to avoid audible hiss.