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TUNING REPORT DANIEL SERUNJOGI TRANSDUCER THEORY
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Overview
The speakers I built, the DKS 800, had design goals that were aimed towards general listening.
This required the speakers to have an even sound as well as cover as much as possible the full
spectrum of hearing. Coloration of sound and distortion were to be avoided as much as
possible.
The DKS 800 were designed to be two way, medium sized stereo pair. They had a 2nd order
Linkwitz-Riley crossover cover the hearing spectrum from around 100 Hz to 30 KHz.
This document covers the results and the process of what was done to reach these goals.
Testing equipment included a Mac Mini, the MOTU interface, and a speaker testing software
program called Fuzzmeasure, which provided the graphs in this document. The speakers were
tested five feet off the ground with a testing microphone one yard directly in front of it. In
between the microphone and the speaker being tested were two flat panel absorbers to
minimize the sound of floor bounce. The testing was done in McArdle theatre, which has inbuilt
dampening curtains that were used as well to minimize echo.
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Initial Testing and Crossover Configuration
Figure 1: This was my initial test of my loudspeaker box. As can clearly be seen, there is a
Extreme drop from 1K downwards and there is a very high peak right after 10K. Both of these
were problems were resolved. The dip was fixed after I rearranged the dampening material and
the peak after 10K was resolved after applying the microphone calibration.
Figure 2: Tweeter with no crossover.
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Figure 3: Woofer with no crossover.
Final Testing
Figure 4: This is the overall final frequency response. I made my crossover point at 3K and the microphone calibration took care of the large peak after 10K.
Figure 5: This is the impulse response of the entire system. Red: 0 degrees,
Purlple: 15 degrees, Blue: 30 degrees, Green: 45 degrees, Yellow: 60 degrees.
Figure 6: Difference of left and right speaker.
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Figure 7: Minimum Phase of entire system.
Figure 8: Step Response for entire system. (Vertical Axis) Red: 0 degrees,
Purlple: 15 degrees, Blue: 30 degrees, Green: 45 degrees, Yellow: 60 degrees.
Figure 9: Entire system (Vertical Axis) Red: 0 degrees, Purlple: 15 degrees, Blue: 30 degrees, Green: 45 degrees, Yellow: 60 degrees.
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Figure 10: Waterfall plot of entire system.
Figure 11: Harmonic Distortion for entire system.
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Figure 12: Entire system horizontal axis. Purlple: 0 degrees, Red: 15 degrees, Green: 30 degrees, Blue: 45 degrees, Yellow: 60 degrees.
Tweeter Performance
Figure 13: Tweeter with crossover.
Figure 14: Tweeter vertical axis. Red: 15 degrees, Green: 30 degrees, Blue: 45 degrees,
Yellow: 60 degrees.
Figure 15: Tweeter impulse response. Purple 0 degrees, Red: 15 degrees, Green: 30 degrees, Blue 45 degrees, Yellow: 60 degrees.
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Figure 16: Tweeter horizontal axis. Green: 0 degrees, , Red: 15 degrees, Purlple: 30 degrees, Blue: 45 degrees, Yellow: 60 degrees.
Figure 17: Tweeter harmonic distortion
Figure 18: Tweeter waterfall plot
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Woofer Performance
Figure 19: Woofer with crossover.
Figure 20: Woofer Horizontal axis. Purlple: 0 degrees, Red: 15 degrees, Green: 30 degrees, Blue: 45 degrees, Yellow: 60 degrees.
Figure 21: Woofer horizontal axis Purlple: 0 degrees, Red: 15 degrees, Green: 30 degrees, Blue: 45 degrees, Yellow: 60 degrees.
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Figure 22: Woofer harmonic distortion.
Figure 23: Woofer step response. Purple: 0 degrees, Red: 15 degrees, Green: 30 degrees, Blue: 45 degrees, Yellow: 60 degrees.
Figure 24: Woofer minimum phase
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Figure 25: Woofer vertical axis. Purple: 0 degrees, Green: 15 degrees, Red: 30 degrees, Blue: 45 degrees, Yellow: 60 degrees.
Figure 26: Woofer waterfall system.
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