(Blog author here) If you check out the spectrograms you'll see that there are a lot of different frequencies in the audio. I wasn't sure if the most powerful f

(Blog author here) If you check out the spectrograms you'll see that there are a lot of different frequencies in the audio. I wasn't sure if the most powerful frequency would be the true rotation rate, so that's why I wanted to have a separate method to check. However, as TheLoneWolfing mentioned, it turns out that the most powerful frequency is indeed once per revolution.