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Old 09-30-2011, 06:08 AM
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The_Aleman The_Aleman is offline
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Join Date: Jul 2008
Location: el People's Republik de Kalifornistan
Posts: 2,658
Default Re: Don't know, how loud?

Originally Posted by Dan View Post
I have to disagree with pointing a muffler down. It will actually "bounce" the sound (echo) most especially off paved road. Is why first responder's sirens are placed low on vehicles. Can "skip" the sound waves like a stone and will travel better.
Disagree all ya like, but asphalt has a diffusing effect on sound waves due to it's surface. Sounds travels faster through air than reflecting off the rough surface of asphalt. It's not like rocks in a canyon; it's surface is even more granular and porous. Also, first responder sirens are placed where they are because they project sound like a powerful speaker - vehicles are in the cone front and rear - not because, as you claim, the sound reflective properties of asphalt.

The loudest horns don't point down. They point so that their cone of sound has maximum effect.

Buy a sound meter and really test em. One 2 stroke with exhaust tubing at the end and pointed aft. Also, I have always wondered how the 4s are in regard to the 2 smokes. I personally enjoy their sound much more. More of a hum like a lawnmower.
I don't have a decibel meter, but when I converted my 4-stroke's exhaust to flexpipe, I played around with the muffler position quite a bit. It was quietest when pointing down when I was 50 feet away, but I just couldn't get it to look good. Hence, it's the way it is now. I still plan on putting a 90-degree elbow for a tip out of the muffler, I'll report on that when I get around to it.

Originally Posted by decoherence View Post
dan is right.
the same reason makes sound carry across lakes & pools.
I don't think he is. And the surface of water is nothing like asphalt. Besides, I still believe that an exhaust pointed perpendicular (or near to it) to water would be quieter at a distance than an exhaust pointed parallel with the surface of water. It's just physics.
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