A SolidState Ion Tweeter

1
A Solid-State Ion Tweeter

• Our Team Members
• Rob Alejnikov
• Mark Blattner
• Colin Joye
• Our Advisors
• Dr. Robert Caverly
• Dr. Pritpal Singh
• Dr. Joseph Kozikowski

2
Presentation Objectives

• Need Identification
• Project Objectives and Analysis
• Possible Solutions
• Strategy

3
Need Identification

• Increase the Range of Optimal Listening Area
• Quest for higher Quality Sound Reproduction

4
Off-Axis Frequency Response

• Conventional Speakers
• Frequency Response
• degrades as Off-Axis angle increases
• Must be On-Axis for Optimal Frequency Response
• Constructive and Destructive Interference causes
  unpredictable Frequency Attenuations

5
Project Objectives

• Create a Device that Offers the Same Frequency
  Content in all Directions
• Concentrate on High Frequencies Since They Tend
  to Beam the Most

6
Possible Solutions

• Line Source
• Emits a Line Dispersion Pattern
• Omni-Polar Siamese Tractrix
• Produces Radial Dispersion Patterns
• Hypersonic Pseudo-Point Source
• Offers Hemispherical Dispersion Patterns
• Omni-Directional Point Source
• Radiates Spherical Dispersion Patterns

7
Types of Sources

• Line Source
• Solves Vertical Positioning
• Does not solve Horizontal
• Omni-Polar (Siamese Tractrix)
• Solves Horizontal Positioning
• Does not solve Vertical

8
Types of Sources (cont.)

• Hemispherical Source
• Solves Horizontal and Vertical Positioning
• Uses Beat Frequencies
• Requires specific physical positioning
• Point Source
• Solves both Horizontal and Vertical Positioning

9
The Point Source Decision

• The Point Source Offers Nearly Ideal Spherical
  Dispersion Patterns
• Corona Discharge Creates a Nearly Ideal Point
  Source
• Use of Corona
• Allows for a More
• Perfect Transient
• Response

10
Point Source Implementation

• Ion Flame
• Best Practical Point Source
• Existing Ion Tweeters use Vacuum Tubes, creating
  Excessive Heat
• Higher Efficiency could lead to wider Frequency
  Response
• Goal
• Raise Efficiency, then widen Frequency Response

11
Strategy

• Model Corona Discharge as an RLC Circuit
• Model Existing Ion Tweeters with above model
• Design and Build Efficient, High-Voltage Circuit
• Control High-Voltage Circuit With Audio Signal
• Time Permitting, Upsize High-Voltage Circuit
• Time Permitting, Design/Build Power Supply

12
Semester Plan
13
Join Us

• At http//ee.vill.edu/ion to Monitor Our Progress
• References
• Olson,Harry F. Modern Sound Reproduction. Van
  Nostrand Reinhold company, New York, 1972. Pg30
• Web References are Located on Our Web Page
• Questions????