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      07-23-2013, 07:10 PM   #104
ProbyOne
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Drives: Acura TL / E93 M3 / 996
Join Date: Nov 2010
Location: LA

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Check out the video at 3:07

1. Try to match the frequency of the observed sound which I estimate is around 350 Hz.

2. Figure out the speed of the car away from camera. It sounds like the top of 3rd gear which should be around 90-100 mph depending on gearing.

3. Correct for Doppler effect. Easy if you can Google. http://www.wolframalpha.com/input/?i...400Hz%2C+90mph

So again, it sounds pretty close to 8000 rpm. It's way better than a guess.
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