Frequency modulation and music synthesis

This article comes from the AMS (American Mathematical Society). The article talks about wave frequencies and also Frequency Modulation. When we hear noises (music) our brains are processing the sound waves. They also state that sound is created by different types of air pressure. Frequency Modulation is just that. Modulating a signal so that it matches another signal. I want to use this article to study the perception of music and noises