Chrome Music Lab is a browser-based music tool for experimentation and mainly just messing around. It includes things like a spectrograph, “voice spinner” and many more. If you’re interested in experimenting with these things I would challenge you to create something from a tool that you have never heard of! This also allows you to experiment and learn about things like music theory through experimentation. If you would rather have the “book” version of music theory, then the website “Musictheory.net” is a great resource.
https://musiclab.chromeexperiments.com/
The Learning Repository 