I see others have already filled in whilst I was working and practicing (thanks guys!)
Toole and Everest are good reads on acoustics; Everest is a bit more lay-friendly IMO. Wikipedia also has some decent overviews on basic electronics, but of course you have to know the names of the terms to know what to look for. Amir's vids are an excellent overview IMO. Another good read is Ethan Winer's The Audio Expert
BTW, some engineers do remember a little math.