Web Audio and Visualisation

I have recently been using Javascript , HTML canvas and web Audio Api for creating audio visualisation . I have made whatever my imagination took me too . But i need more to dig up , Actually i need ultimate sources to study how to apply MATHS in creating animation Using CANVAS along with how to extract BASS , TREBBLE , and other sound energy from audio we fees into , IN SHORT I NEEED , BOOK OR OTHERE REFERENCE TO READ DEPTH OF HOW FOURIER TRANSFORM EXTRACTS DATA FROM SOUND AND HOW MATHEMATICS CAN BE USEFULL TO DISPLAY ITS CHARM IN FORM OF VISUALISATION.