Car Audio Competition is a competition rewarding the person who can produce the loudest sound inside a vehicle. The "dB" means decibels of sound pressure level (SPL).
In these competitions, SPL (Sound Pressure Level) of 155 dB can be reached, and it is not unheard of to see 160+ dB as well.
Competitive vehicles can range from a small vehicle with a single amplifier and subwoofer up to a large van with dozens of amplifier and subwoofer powered by dozens of car batteries and with upgraded electrical wiring and alternators.
During a competition, the vehicle must be driven 20 feet. Nobody is allowed to sit in the vehicle during trials because injury would be certain. The vehicles are sealed tight to maximize containment of the sound energy for the decibel level meter. The competitor stands away from the vehicle with an on/off switch control while a computer voice announces the stages for the "races". The test tone consists of a very short resonating tone between 30 Hz and 70 Hz, called "the burp".
