GDX2

Overview

This 2-way desktop/bookshelf stereo pair was designed to be used for general music listening, as well as mixing.  With a ported cabinet, this system has an F3 of around 80 Hz, giving a good representation of bass frequencies without necessarily needing a subwoofer, though one can be used for added fullness.  Designed on a budget, this pair cost just under $500, giving high performance at a relatively low cost.

Goals:

• Small size for desktop use, as well as portability.
• Low frequency extension.
• Flat frequency response.
• Budget of $500.

Features:

• 2-way system.
• Passive crossovers.
• Ported cabinet for low frequency extension.
• Flat response curve (variation of 1.5 dB.)

Cabinet:

• 3/4″ 11-ply birch exterior.
• 1/2″ MDF interior.

Drivers:

• SEAS Prestige h1141 5.5″ aluminum cone woofer.
• SEAS Prestige h1211 1″ textile dome tweeter.

Documentation:

Initial Design Statement

Drafting Packet

Final Testing Report

Speaker Glossy

Testing Results:

Overall

Green: Overall. Blue: Woofer. Yellow: Tweeter. Purple: Port

Frequency Response Curve

Inverted Polarity on Tweeter

Crossover Filter Response

Green: 15 degrees. Blue: 30 degrees. Yellow: 45 degrees. Purple: 60 degrees.

Horizontal Off-Axis Response

Red: 15 degrees. Green: 30 degrees. Blue: 45 degrees. Yellow: 60 degrees.

Vertical Off-Axis Response

Step Response

Impulse Response

Waterfall Plot

Minimum Phase Plot

Harmonic Distortion

Tweeter

Frequency Response

Purple: 15 degrees. Red: 30 degrees. Green: 45 degrees. Blue: 60 degrees.

Horizontal Off-Axis

Blue: 15 degrees. Green: 30 Degrees. Red: 45 degrees. Purple: 60 degrees.

Vertical Off-Axis Response

Tweeter Left/Right Difference

Step Response

Impulse Response

Green: Tweeter. Purple: 6 Ohm Resistor.

Tweeter Impedance

Harmonic Distorion

Woofer

Woofer Frequency Response

Purple: 15 degrees. Red: 30 degrees. Blue: 45 degrees. Green: 60 degrees.

Horizontal Off-Axis Response

Blue: 15 degrees. Red: 30 degrees. Purple: 45 degrees. Yellow: 60 degrees.

Vertical Off-Axis Response

Woofer Left/Right Difference

Step Response

Impulse Response

Yellow: Woofer. Blue: 8 Ohm Resistor.

Woofer Impedance

Harmonic Distortion

GDX2 by Grant Prusi is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.