USEFUL LINKS:

Neat websites re:  Fourier Analysis and Synthesis:
http://www.phys.hawaii.edu/~teb/java/ntnujava/sound/sound.html
http://sunsite.univie.ac.at/Spreadsite/fourier/fourtone.htm
http://hyperphysics.phy-astr.gsu.edu/hbase/audio/geowv.html#c1
[or do a Google search on 'Fourier analysis' and explore for yourself]