When you go to a contest, look for vehicles and systems that are similar to yours. 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. There are several reasons for this. 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. This allows the alternators to produce full output under a loaded condition.