I have finished the near final draft of an on-line, free, interactive textbook for an introductory physics of sound course that I teach to non-science majors. It is interactive in the sense that there are embedded applets (Physlets from W. Christian at Davidson) and sound files, etc. Please feel free to send me comments, corrections, suggestions (offline please) or use it in your class. I will continue to make
corrections and there are a few things I will eventually add but basically it is in final form.