Understanding Sound as a Wave We all remember from school physics that sound travels as a wave. Something initiates the wave, it travels through the air, reaches our ears, and we perceive it as sound. In music, what initiates this wave is either the human voice or a musical instrument. At the source of vibrations, they are typically very weak and need a resonating body  to amplify them. This resonating body is what completes the instrument: In voice:  The wave is initiated in