As a music composition major now in 4th year ECE major, I think the math aspect is often glossed over, but is essential for things like acoustical engineering, synthesis, and the future of music innovation(dominated by computation). Here are some general ideas and associated keywords. In addition to search engines, search class listings at any university site, and get their syllabus and book list. This is easiest way to find related books online. And a wealth of keywords all outlined. I would be happy to reference direct classes if you are interested.

A thorough understanding of trig and calculus is essential. This will allow you to understand the different waveforms and how they are analyzed. Discreet mathematics will help a lot as well.

Physics is then next, understanding how energy and physical mechanisms are used and how they relate to sound production and propagation. Other useful and difficult subjects like damping are covered. General physics is important because you will also learn about electrical potential and circuit analysis. More on that below.

Study digital logic in computer science, and how things like sampling and a/d conversion work. Important because the variety of waveforms you can produce with circuits and software is beyond encyclopedic. There is stuff yet to be invented!

Then comes analysis of complex waveforms. The best way to do this imo is studying circuit response. Why? Well stick a speaker on there and it is transcribing the circuit waveform! There are just so many analogs to actual sound waves it is truly fascinating. Check out signals and systems, an electrical engineering subject. This is a challenging subject. Laplace and fourier transformations are super useful. At this point you should know where to proceed, and will understand how a lot of music is generated and recorded.