2 definitions for F

  Flutter : Caused by speed fluctuations on tape of vinyl, causing fluctuations in pitch. This is caused by transport problems which in turn means the tape or vinyl slows down or speeds up.

  Frequency : This is the number of complete cycles a sound wave does in 1 second. A pure sine wave would go from -1 to 1, and then back down to -1 again. Music or speech would have many fluctuations, but would still range from -1 - 1. 1Hz = one full cycle from -1 to 1 per second. Audible frequencies range from 16Hz - 20,000Hz.