ACOUSTICS. Leo L. Beranek. Source of practical acoustical concepts and theory, with information on microphones, loud-speakers and speaker enclosures, and room acoustics.
This is the book to get to learn about acoustics from one of its original founders of the science and engineering in the field. I prefer it to the later book jointly authored with Mellow but that is OK if you can’t get this earlier edition. Beranek is a good teacher and the ideas flow naturally, but succinctly. Equations are used only to inform, not intimidate.