Math doesn’t influence my playing style at any conscious level. I approach playing more as a free flow of feeling.
I taught an honors section of MAT 115 (a gen ed course) on math and music twice. However, it’s tough to devote an entire course to math and music when you can’t impose prerequisites that would make it easier to discuss more topics. For instance, it is limiting to discuss math and music if you cannot assume students have some knowledge of trigonometry. I find it easier to just incorporate certain topics in math and music from time to time in regular general education math classes.
Frets on a guitar are separated not so much logarithmically as exponentially. The pitches one gets on a guitar are the same pitch one gets on a piano or even-tempered tuning. Since the frequency at one note must be doubled to get what we hear as an octave, and western music divides one octave into 12 half-steps, to go from one note up one half step, multiply the original frequency by 2^(1/12). That means if you start with frequency f, then a twelve-step chromatic scale up from f would be 2^(0/12)f, 2^(1/12)f, 2^(2/12)f, 2^(3/12)f, 2^(4/12)f, 2^(5/12)f, 2^(6/12)f, 2^(7/12)f, 2^(8/12)f, 2^(9/12)f, 2^(10/12)f, 2^(11/12)f, 2^(12/12)f = 2f.
When I play, I don’t think in terms of frequencies. I think in terms of half-steps. The one exception to that is when I tune my instrument to others. In that case I’m adjusting the lengths of the tubing of my trumpet to better match the frequencies of others. There are some interesting techniques like “beats” one can use to help in these adjustments. The idea of beats is an interesting topic in differential equations.
No one knows for sure why octaves are so basic, but it is assumed that it comes from the fact that adult male human voices tend to be an octave lower than female human voices. Although the mathematical nature of octaves was probably noticed by others, the first historical record for this fact that I am aware of was from ancient Greece’s Pythagoras (500 B.C.)
Speaking from experience, I’ve made much more money doing mathematics that includes some music over doing only music. In fact, I’m pretty sure I’m running a deficit on the music.
My favorite tune depends on what kind of mood I’m in, what I’m currently thinking about, and lots of other variables. I will say that flamenco music is my favorite genre, and the instrument I enjoy HEARING the most is guitar. (Okay, if you twist my arm, I might say my favorite tune is “Volaré” especially as performed by The Gypsy Kings. Wait, no, my favorite song is Samuel Barber’s “Adagio for Strings.” On the other hand, maybe my favorite is …)
It depends on what you mean by a full composition. I have used Mathematica for music composition in two ways.
I play in the band so I don’t have to dance. In other words, I can’t swing dance.
The Math Behind the Music by Leon Harkleroad is probably the most interesting book I have read on math and music. I wouldn’t call it research, but more an overview of some areas of commonality between the two disciplines. In terms of research: