How Is Sound Produced

1
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

2
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.

3
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.

4
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.

5
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.

6
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.

7
Team Members

• Group 21
• Rob Alejnikov
• Mark Blattner
• Colin Joye

8
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

9
Advisors

• Academia
• Dr. Robert Caverly
• Dr. Joseph Kozikowski
• Dr. Pritpal Singh
• Industry
• Mr. Joseph Fell

10
Audio Subsystem Simulation