Thread: Exhaust dB data
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Old 05-06-2005, 06:54 PM   #90
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Originally Posted by badboiWRX
Thats a nice test and all, but its not accurate to CA standards... and the calibration might be off on your meter when compared to official state testing equipment.

CA standards test it at 4500rpm, for reference. With a 95 dB limit +/- 1.5 dB for error. With my Radioshack analog meter, I tested 92 dB on my set-up, where the official reading by the State Referee is 95.1 dB. Thats quite a difference... but not to the human ear. 5 dB's isnt even really detectable by ear...
Actually, 5 db is _definitely_ noticeable.

Some people are able to notice a 1 db difference in volume, 3 db is considered a 'moderate' increase, 10 db is perceived as a doubling of volume.

I think it's great that Unabomber is doing this testing -- it is the kind of thing NASIOC could use more of.

I am only trying to make his work even more useful by explaining how spl given as a 'db' reading relates to how people actually perceive (or hear) sound.
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