physics of sound
This is the first section of smackmypitchup.com curriculum. You can read the classes in order or freely skip forward and backwards as you please. Every subject has a set of tests related to it, so make sure you do the tests before going on too much with the reading. If you see that you are not proficient with the tests, you probably need to review some subjects.
The first section is dedicated to sound as a physical phenomenon: enjoy!