I do not have a background in electrical engineering. I do have experience building audio equipment from kits and I can build circuits from schematics diagrams.
What I would like to do is to be able to build more creatively. I don't think I will be able to do this without a more rigorous, abstract understanding of how audio signals are generated and manipulated in hardware though.
I would like to study some essential theory but I don't want to get an entire electrical engineering degree. What would be the most direct way to gain this knowledge? (a certain course, book recommendations, etc)