dB drag racing

dB drag racing 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, Sound Pressure Level (SPL) of 155 dB can be reached, and it is not unheard of to see more than 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 amplifiers and subwoofers powered by dozens of car batteries and with upgraded electrical wiring and alternators.

There were 10,000 competitors in 2003 and 300 "races". U.S. National Championships were held in Tennessee.

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".

For comparison:

• 163 dB—Windows break
• 150 dB—Jet engine at 30 m ^[1]
• 140 dB—Threshold of pain ^[2]

The perceived loudness doubles with every 10 dB increase.^[3] Direct comparisons, however, can only be made with the same measurement techniques, and the same weighting scale.

Sources

1. ^ MIT solutions set
2. ^ Decibel Equivalent Table
3. ^ Wolfe, Joe. "What is a decibel?". School of Physics,University of New South Wales. http://www.animations.physics.unsw.edu.au/jw/dB.htm#log. 

• dB Drag Racing Website
• "This American Life" radio broadcast ("Auto Show").
• Extreme SPL Racing
• CNN report
• World Record 180.5 dB from a Single Subwoofer