How Is Sound Produced? • Tweeters Use Corona Discharge to Produce Sound • Corona is Produced by Dielectric Breakdown Of Air due to Extremely High Voltages • Varying Voltage Causes Size of Corona to Vary • Variation in Corona Affects Surrounding Air Pressure Causing Sound
Enhancements • More efficient use of power due to use of modern semiconductors instead of vacuum tubes. • Wider Frequency response Expected from a higher power Efficiency • Smaller physical size of system. • Less heat radiated by components.
Coil Research • Forms resonant circuit due to winding self-capacitance • Coil wound with thick wire to minimize resistive loss. • Uses air-core coil for minimal hysteresis.
Why Use Ion Tweeters? • Nearly perfect transient response • Omnidirectionality • Normal tweeters beam high frequencies, distorting off-axis sound. • Ion tweeters have equalfrequency content in all directions.
Specifications • Resonant high voltage oscillator operates at ~9.1MHz. • Output voltage to sustain corona discharge must be greater than 20,000 volts. 1 millimeter of corona forms for every 2,000 volts above this reference. • Power consumption to be less than 200watts.
Oscillator Theory • The use of feedback keeps the coil locked in at its self-resonant frequency. • The feedback signals interrupts current via the switching device. • The quickly changing current in the coil causes high voltage to be produced.
Team Members Group 21 Rob Alejnikov Mark Blattner Colin Joye
Specifications & Frequency Response • Gain • Variable from zero to 60 • High Pass Filter • Cutoff at 2 kHz, 12 dB/octave • Low Pass Filter • Cutoff at 40 kHz, 12 dB/octave • Low Power Consumption • Consumes 0.36 Watts • High quality op-amps • LF356 audio op-amps
Advisors • Academia • Dr. Robert Caverly • Dr. Joseph Kozikowski • Dr. Pritpal Singh • Industry • Mr. Joseph Fell