Journey with Deafening Sound to the International Sound-Off in Kansas City, Missouri, where cars and drivers compete for highest volume, not speed.

This particular car show is considered the Super Bowl of car audio. Proud owners take cars weighing just over a ton at purchase and load them down with so many sound-producing componenets, and so much heavy-duty steel plating, that by the time the boom car of their dreams is finished, it may end up weighting as much as three tons.

As StereoWest manager Steve Abbott (pictured below) points out, these cars have actually moved beyond sound -- they have no mid and high speakers and don't actually play music. What they do primarily is create pressure, and their sound system's output is measured by its SPL, or sound pressure level. Some of the cars shown in Deafening Sound are capable of producing sound just as loud as the shuttle on its launch pad.

Abbott says it's not uncommon for customers (usually 16-to-24-year-old males) to spend $2,000 on a set of speakers. Properly equipped, our proud new boom car owner can produce sound above 170 dB. To put that in perspective, he adds, if you stand behind the jet engines of a 747 the dB reading will only be in the high 150s.

Since most authorities agree that continued exposure to sound above 85 dB can, over time, cause hearing loss, the management of boom car sound presents a real potential health hazard for their owners. One owner shown at the Sound-Off admitted that he doesn't listne to his system that much because "I'd go deaf if I did."

  Video 2: International Sound-Off