Really recommended, complete and easy to understand:
Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, by Floyd Toole
The best information comes from Audio Engineering Society, some information is free but you need to register and pay a yearly fee to have access to the whole library.
Very recommended about FIR correction is Denis Sbragion DRC documentation.
To go a bit deeper than Toole’s book, I would highly recommend to read Earl Geddes, David Griesinger and JJ Johnston presentations, books and articles. “creme de la creme” in audio !