This was the first time I entered a sound contest with my boat, but I understand how sound pressure waves travel. After I found out that the mic would be on the front seat I made the decision to unplug the subwoofer in the back of my boat so my measurements were done with only my single 12 facing the driver playing. I also put towels between around the driver's seat to trap the air coming from the sub as well as moving an ice chest to block the left side of the driver's seat.
Before the test I went out in the lake and played three different test tracks to set the maximum clean levels, a 200-20hz sweep, and two different "warble" tracks. The warble tracks are good because you get four or five sweeps through the range in the 30 second test period, this allows you to make adjustments on the fly and see how things react. In my first test period I made a few adjustments including cranking my sub into distortion. I only pushed 125db before my amp started distorting, having plenty of gain remaining I pushed it hard into distortion and got a 136db during the first test. At that point I decided that I could afford another Wetsound XS12 and I need a good excuse to replace the old HiFonics boat anchor driving my bass, so I pushed all the gains to the limit. This pushed the sub into serious distortion, I am talking square wave territory during the 200-20hz sweep tone. After 30 seconds it also smelled like I was burning toast under my driver's seat. There was a nice new ring of discoloration behind the plastic woofer cone where the voice coil attaches to the cone.
Before the tower test I asked Mike (the test manager) what frequencies would be sampled for the tower test. Mike looked a bit perplexed with my question then offered two answers: "all of them" or "I don't know" and to just let it rip. At that point he said that he would just leave the mic on the edge of the patio boat for the tower test. When I explained that the mic was beyond the cutoff angle for my tower speakers we decided it might work better if I swung the nose of my boat around so my tower faced the mic, I also plugged my rear subs back in. For the tower test I planned to play a track with lots of range but heavily biased toward the mid/high frequencies where my tower speakers are happiest. During the first 30 second test I tweaked my EQ only to discover the mic responded more to bass adjustments than it did to mid/high frequency adjustments. This told me that the tower test was more of a rear subwoofer test than a tower test. This explains the results shown for the tower test below.
DRIVE BY
1
139.0
Donald Graham
2
133.5
Scott Bilyou
3
132.0
Joe Mitchell
4
131.0
E's Boat
5
129.7
Shawn Hammond
6
127.8
Brian Mitchell
7
126.6
Mike Jolley
Ken Holmgren
8
125.3
David Eckhardt
If we continue to test using this protocal I predict a boat will catch on fire pretty soon. Overdriven high-power electronics mounted in fiberglass and plastic is a great recipe for a fire.
I would like to see a SQ requirement to keep guys like me from pushing their equipment waay past the reasonable level in a crazy attempt to make the meter jump.
There should also be some rules so somebody like me doesn't show with some appartus like the one show below aimed right at the mic... (allowing me to get a real/reproducable reading in the 150db range)
(Message edited by mikeski on May 06, 2008)
(Message edited by mikeski on May 06, 2008)