Thanks for attending my recent PA & Audio Workshop. Here are links to interesting 
documents, websites & software which may help explain some of the topics covered.
I can be emailed here or visit my homepage.   RW
Downloads:

Introducing an external DSP (.doc)
Parameters of a sound wave (.doc)
Basic sound definitions (.doc) 
Heinrich Hertz (.html) 
Making The Most of Your Mixer (.pdf) 
Short Course in Digital Audio (.zip) 
Keyboard Frequency chart (.jpeg) 
Guitar Frequency chart (.jpeg) 
The Harmonic Series (image) (.jpeg)
The Harmonic Series (audio) (.ogg)
The Fletcher-Munsen equal loudness contours (.gif)

Software:
Feedback Trainer (.zip) 
Sine Wave Generator (.zip)
Oscilloscope_132 (.zip) 
Tone Generator (.zip) 
Delay Calculator (.zip)
Note Attack! (.zip)
Metronome (.zip)

 Audio links:
Music and Sound Waves
Physics Classroom: Sound Waves & Music
FX explained
Phantom Power
Microphone polar response characteristics
Sine Wave Applet
Lissajous Lab
Sound Engineers Survival Guide
History of Sound Recording
Intro to Digital Audio
How we hear
The Ear
5.1 Surround Sound
ISO preferred numbers
Vocal Tract Acoustics
Guitar Acoustics
Sound Spectrum
Audiophile links
Shure eLetters
Shure guides