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dB Drag Racing
Exedore writes "For a paltry $80,000 outlay, you too can fight back against the punk kids blasting gangsta rap from their Honda Civics. Enter the strange (and rather loud) world of dB Drag Racing and join a small group of dedicated competitors in their quest for the loudest car sound system possible. The numbers: 130,000 watts output, 177dB, 10,000 lbs. of equipment (including the vehicle and all the sound insulation needed to protect those nearby). It might not be quite up to Disaster Area standards, but it's not far off."
Go to www.4hv.org, go to the buy and sell thread, and ask someone if they will sell you a HERF unit, and tell them what you need it for.
From the article: "every 10 dB increase equivalent to a doubling of perceived sound."
In high school physics, I was taught that an increase of 3dB doubles the intensity/amplitude of the sound. My teacher concluded that +3dB would mean you hear a sound twice as loud. Then he went on to explain that P (power) is directly proportional to 1/d (the inverse of the distance squared).
I know that the Richter scale works on the idea that an earthquake of 6 on the Richter scale is double the strength of one of 5 on the Richter scale.
But have I been mislead? Is "perceived sound" different from amplitude/intensity? Did I really get staight 'A's in pyhsics?
Mike
Tux, myself and my lady regularly engage in 3somes - over the home network.
The sound control works on a mixture of sheer volume and psychological effects; strictly speaking it's not a directly physical effect.
I really don't care to think of what would happen if a persons resonant frequency was "accidentally" broadcast.
Only in Star Trek does everything have a resonant frequency. "People" do not have resonant frequencies; we are too soft and too squishy. In order to have a resonant frequency there must be some kind of resonance, which arises because the waves (whatever they are) are sharply and cleanly reflected, and can reinforce each other. When they are mushed up, they cease to resonate and you get more normal, mundane effects.
Certain parts of the body, mostly bone, can have a resonant frequency, but everybody's will be different. In fact, if you try, you can probably locate your jawbone's resonant frequency. Every once in a long while (on the order of once every couple of years), something will manage to hit one of my bone's resonant frequencies loud enough to be very unpleasent, generally construction equipment. Even so, my bones didn't crumble for various reasons, including the fact that even bones don't have very good resonant frequencies, and it's embedded in a soft goo.
So you can't simply broadcast some magical noise and watch the crowd dissolve. Of course you could kill them with pure power; an explosion's concussion can do that. But that isn't really "sound" in the traditional sense (no real periodicity, just one burst, maybe two or three significant oscillations (for nuclear-sized blasts), and that's it; the essense of "sound" is the wave nature).
Star Trek really promotes some bad science here; really strong resonance, strong enough to hurt things, is not an every-day, everywhere-you-look phenomenon. Simple observation will confirm this fact; despite the wide variety of noise in the modern world, things conspicuously fail to blow themselves to smithereens because something was hit by its resonant frequency. It's the exception rather then the rule. You need a very regular structure that's also very hard, which doesn't happen much in nature. The reason we see any significant effects at all arises from our tendency to build regular and hard structures, like Tacoma Narrows or your shower (a rectangle box lines with tiles? Show me something like that in nature!).
A similar answer to this message's grandparent: You can pulverize some things with sound, but mostly just hard things. The technology is pretty simple and if it's easy or useful, it's already being used in industry somewhere for something. You don't sound used as a pulverizing weapon because it's useless for that purpose. Generally, if you're trying to pulverize something it's easier to just hit it (not being sarcastic), but I've seen some exceptions (and even that is just "loosening" things with sound, it's sound plus "conventional" pressure and some rotation that all comes together to do the drilling).