• Audio Signal Processing and Coding
• Loudspeaker Handbook
• Psychoacoustics: Facts and Models (Springer Series in Information Sciences)
• Speech Enhancement: Theory and Practice (Signal Processing and Communications)
• Digital Audio Signal Processing

Great book on Audio Bandwidth Extension
Review written by: Robbert Corbit From Texas
Audio Bandwidth Extension pulls, as far as I know, a lot of new types of signal processing together.
It is very readable and is a source of many references including very recent ones.
I'm not a specialist but for me as a postgraduate student it was very readable and a great help in the understanding of the nonlinear processing and it psycho-acoustical consequences. Also the patent review was new to me and gave a nice insight in the evolution of this type of processing.