Concept
Version 6
Created by Boundless
Volume
A sound wave with its frequency (pitch) and amplitude (loudness) labeled
Higher amplitude will be perceived as louder sound.
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"SoundWaveDiagFreqAmp."
http://commons.wikimedia.org/wiki/File:SoundWaveDiagFreqAmp.png
Wikimedia
Public domain.