What is music theory?
The term “Music Theory” is used to describe the study of how and why music sounds right or wrong. In other words, the purpose of music theory is to explain why something sounded the way it did and how that sound can be made again. It’s learning the building blocks of music, and being able to zoom out and have a comprehensive understanding of how to organize different sounds.
Online Music Theory Resources
https://www.musictheory.net - Music Theory lessons and exercises.
The Amazing Slow Downer - A tool for slowing down music and transposing.
Tenuto - App for phone/tablets, great for note naming exercises.