Chris-PA
Where the Wild Things Are
Unless you use some sort of pitch correction processing (like they use nowadays to make talentless drones seem like they can sing), it is hard to change the frequency of a signal (acoustic or electrical) in natural systems. You can selectively filter the frequencies out or amplify them, but you can't easily change them.I have a feeling there would be to many variables to consider. A muffler mod will change the pitch of the exhaust. Well I guess I am assuming it goes by sound unlike spark wire pulse's.
Humans are very good at image recognition, so it is not too difficult to look at a plot and see the lowest large spike and the harmonics (integer multiples) above them, and to separate that pattern from the noise blob below. But it's tough to do that in software, especially when you can't anticipate the type of thing you are looking for or the shape of the noise floor. That's what those setup parameters are for - to try to narrow it down.Sound is nothing more than vibrations, which can be measured, exactly what Chris has done. A muffler mod will change tone but not pitch.