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Is this thing turned on?.....

Hello.....anybody here?




Funny you should ask.

I took the audio from the Daniels run and had one of my Scientists look into this for a few minutes. He ran the audio through a Sonar tool (Jonesie' tracking Red October) we have and did a Spectrogram plot (do not know how to attach). Need another Scientist. Ha! The red lines are the engine harmonics which are directly related to shaft rate and engine RPM. The gear shifting is clearly visible and lines up with what is heard in the video.



FINDINGS: Zooming in down below 100Hz and increasing the FFT integration size you can clearly see the 1st harmonics in exhaust noise. Top RPM was about 4800 in each of the three gears. Second gear might be slightly higher (4830RPM) and Third gear (at the finish line) a little lower (4770RPM). Many higher-order harmonics can also be seen and carry additional useful information. (These are all conservative guesses on the low side and could be higher by 20 or 30 RPM.)



CAVEAT: We are basing this analysis on indirect observation from acoustic energy in the exhaust noises (good thing they don't use mufflers). These were eyeball measurements coupled with FFT length constraints so frequency estimates maybe .5Hz precision. That creates an uncertainty of 30RPM or so. So the top RPM might be 20 or 30 Hz higher. Also there is a curious non-linearity in that harmonics are not exact multiples of each other and varies with frequency. (Note how the harmonic slopes get steeper as freq goes up. We need to investigate this further to interpret these harmonics and get a more accurate estimate of RPM.)


If we need greater precision (reducing uncertainty etc) then we'll need to extract these signals and perform more elaborate analysis.

The program does not care that the engine is a four stroke so for a slight fee I will multiply the findings by two.

PS Thanks to Al Gore for the internet and my friend Jim D. for the noise. Now let's see if the board is working.

I now have the converter and powerband mapped but do not think I should post that data. This is all in fun. The Barton's have "their stuff in one sock"..... GO SAINTS!!!





good one....

im an audio guy.......and i even said to myself .....[Edited by Moparts - Family Friendly Site - Keep it clean]??