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 equal frequency 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

Audio Subsystem Simulation