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

Presentation Objectives

Need IdentificationProject Objectives and AnalysisPossible SolutionsStrategy

Need Identification

Increase the Range of Optimal Listening AreaQuest for higher Quality Sound Reproduction

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

Project Objectives

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

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

Types of Sources

Line Source Solves Vertical

Positioning Does not solve Horizontal

Omni-Polar (Siamese

Tractrix) Solves Horizontal

Positioning Does not solve Vertical

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

The Point Source Decision

The Point Source Offers Nearly Ideal Spherical Dispersion PatternsCorona Discharge Creates a Nearly Ideal Point SourceUse of CoronaAllows for a More Perfect TransientResponse

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

Strategy

Model Corona Discharge as an RLC CircuitModel Existing Ion Tweeters with above modelDesign and Build Efficient, High-Voltage CircuitControl High-Voltage Circuit With Audio SignalTime Permitting, Upsize High-Voltage CircuitTime Permitting, Design/Build Power Supply

Semester Plan

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

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