06-16-2010, 03:44 AM
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CC Member
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Join Date: Jun 2006
Location: Newcastle, Warners Bay,
NSW
Cobra Make, Engine: RMC . 393 Dart alloy block Stroked 351 alloy heads ..all the goodies plus a pre oiler. al
Posts: 1,495
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Quote:
Originally Posted by Excaliber
Rob Smith, sorry I missed the question for so long on this thread! How far away are the DB sound readings taken?
From what I've been able to gather it's like a meter is set up at a particular location on the track somewhere. Like at "turn three" or where ever. 20 -30 ft for sure, I've heard it's more like 50 feet. If you know where it is you could possibly "sand bag" in that area if you know you will be kicked off the track if you don't.
Oregon actually specifies a reading from 50 feet for the State DB levels. But the State rarely enforces a sound limit anyway. You would have to be obnoxious, really loud and rude before it would become an issue on the "street" here. But it IS an issue at various American race tracks!
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For street vehicles the meter is placed at 45 degrees from the exhaust exit at 525mm (20 3/4 ") and the engine is revved hard once. It must be lower than 89 db. The rolling measurement is from 7.5 metres (25 ft) doing 30mph in 2nd gear. that measurement must be 77db or lower. Damn Tuff...the car must sound like a factory jobby.
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