Tuesday, April 7, 2009

THERE'S NOISE, AND THEN THERE'S --- dB DRAG RACING

At this very moment one of our neighbors is having their house sandblasted. It's loud. It's irritating, though tolerable now that they're working on the other side of the house. I'm sure when they're done their house will be much improved for it and our property value will have increased by at least a few bucks for being in such a nice neighborhood.

After last Saturday, some quiet would be nice, though.

dB Drag Races, themselves, aren't all that noisy unless you happen to be sitting in one of the cars in the competition. And people do, some of them. Some of them even sit there, in the drivers seat, with 146.7 decibels of noise assaulting their eardrums (a jet taking off generates something between 130-140 dB) without even practicing "safe sound" (ear protection.)

But the whole point of dB Drag Racing is to generate as much sound pressure as possible within the sealed environment of your vehicle. Every bit of sound that escapes, lowers your score. So from the outside, during the competition, you don't hear a whole lot.

If that's as far as it went, it would be a rather pastoral pastime. But really, what's the point of having speakers like these, or bigger, filling the back of your car, if you can't let them aurally assault the assembled crowd.

Blowing around young women's hair with soundwaves is a neat trick:There's different classes, different voltage levels, all sorts of things. The Hummer that was blowing those girls' hair around in the last two pictures, packed 22,000 watts of power into its amplifiers. (My friend Bill, who was with me on this excursion, has a reasonably large home stereo system with a much more than adequate 500 watts of power.)

So, what happens is that two cars line up and get hooked up to microphones that measure SPL (sound pressure level) which is expressed as decibels. The vehicle that blows the highest number of decibels wins. The high score so far this year is 181.7 dB. (It takes about 163 decibels to break glass. 130 dB is about the average threshold of pain for most people with normal hearing.)
The winner of this particular event, generated 159.6 dB. He did not remain in his car while competing, wisely choosing, instead, to operate his speakers remotely.
There's a whole lot more to it than I've gone into here. And the pictures - without the roar of the speakers when competitors would show off with their windows or doors open, causing their cars to shake, rattle and roll - just can't do it justice. If you want to know more, or find a competition to attend in your neighborhood, you can click on this sentence to be taken to the official website.

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