I found this quaint web page and thought some forum readers might find it useful.
It covers many basic sound topics and may come in handy from time to time.
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/soucon.html
Interesting, thanks!
That was a lot of work! 
I found it interesting and useful and it certainly was a lot of work. 
It’s a good reference set for sound and hearing topics. I like how the material is presented.