 |
Author: Wayne Harris Click HERE to view more articles by Wayne Harris. Originally appeared in the April / May 1997 issue of Car Sound magazine. © All rights reserved. |
If you're a dB Drag Racing competitor, you already know how hard it is to improve your score by even 1 tenth of a decibel. In this series of articles, we will focus on things you can do to maximize your score at a dB Drag Racing event.
Since dB Drag Racing rules specifically prohibit a contestant from being inside of the vehicle during competition, some other method for controlling the sound system must be devised. The two most prevalent methods in use today include infrared remotes and external consoles.
Infrared Remote: An infrared remote is a small, handheld remote control that is used to control vital system functions such as volume, play, pause, etc. Typically, contestants use the IR remote by "shining" it through the side window of the vehicle. Most of the time this works fine. However, I have seen instances where the IR remote would not work through the tint of the window. In other situations, I've seen the batteries in the remote go dead. This is almost always bad news for the competitor.
If you must use an IR remote, always use fresh batteries during competition. Test, test, and retest your unit beforehand to make sure everything is working reliably. Or, better yet, build an external console.
External Console: Most of the serious dB Drag Racing competitors use external consoles to control their system. These consoles are usually small podiums that sit beside the vehicle during competition. At a minimum, the console contains the source unit that will be used to provide the signal to the vehicle's sound system. In more advanced systems, you may even find scopes, volt meters, and even laptop computers incorporated into the console!
There are many advantages to using an external console. They are reliable. You have access to all of the controls on the source unit. You can use a pair of headphones to monitor the program material, which in turn will let you "burp" your system at just the right place in the music. All of these benefits will give you a significant advantage over competitors who don't use consoles.
Selecting the correct program material for your system is usually a matter of trial and error for most competitors. Your goal should be to select a CD that contains frequencies that match the resonant frequency of your vehicle.
Here are a few tips. When you go to a contest, look for vehicles and systems that are similar to yours. What program material are they using? You'll probably notice that most of the pro's use CD's with sweeps or tones on them. Some of the competitors still use Flashdance, a decade old favorite of SPL competitors everywhere. With a little experimentation, you should be able to find a CD that works well in your system. Pandisc is a good source for competition CDs.
Timing is everything. This is especially true in a dB Drag Racing event. Remember, during competition, each contestant only has 30 seconds to achieve their highest SPL. From my judging experience, I have noticed that competitors almost always register their highest number on their first "burp" of the system. There are several reasons for this.
Woofer Voice Coil Temperature: As you play music through a speaker, its voice coil temperature rises. Consequently, so does the resistance of the wire in the voice coil. Since the output power of most amplifiers is inversely proportional to load impedance, an increase in voice coil temperature will result in a decrease in amplifier output power.
Electrical System: Immediately before competition, most competitors increase the idle speed of their vehicles. This allows the alternators to produce full output under a loaded condition. At the same time, the batteries and capacitors in the system will acquire a "surface charge" that is significantly higher than the loaded voltage. This surface charge disappears shortly after a load is applied to the electrical system.
Equipment Failure: Many times, competitors damage system components during their initial "burp." This prevents the competitor from bettering their score after the damage has been done. With this in mind, your strategy should be to wait for just the right instant in the music to burp your system. A typical scenario would look something like this…
You're wearing headphones that are plugged into your external console. Your CD is cued up and paused 10 or 15 seconds before the part of the music you are interested in. The sound system in the vehicle is muted. Competition begins. You now have 30 seconds to do your highest score. While monitoring the output of the CD player, take the player off pause. With your finger poised above the mute button, you wait until just the right moment in the music. When that moment arrives, you un-mute the sound system in the vehicle and blow the windshield out.
Hey, it could happen...
 |
Wayne's World |
This page, and all contents, are Copyright © 1996 by Wayne Harris Enterprises, Mesa Arizona, USA.