Riding the (Sound) Waves

Robert McLassus. Surface Waves.


So what is a sound and how do we perceive it? Just good vibrations? Not quite.

A sound itself is actually a series of pressure waves traveling through a medium (gas, liquid or solid). These waves (or “impacts,” as the ancient Greeks sometimes described them) are caused by a source vibration, which is technically defined as an oscillation around a point of equilibrium. Sound waves, in turn, induce other things to vibrate, such as the human eardrum (tympanic membrane).

So basically, something vibrates causing waves of pressure to issue forth via colliding and rebounding molecules, which in turn causes the eardrum to vibrate, the frequency of which is interpreted by the human brain as sound and pitch.

The frequency of sound is measured in hertz (Hz), which is equal to the number of cycles per second. Human beings can usually perceive sounds between 20 and 20,000 Hz. The slower the frequency, the “lower” the perceived pitch, and the faster, the “higher.”

Another related and very important type of wave in music is that which is produced by a taut, vibrating string. This has an amazing relationship to the frequency of sound, and it’s where we’re headed in the next post. Until then, hang loose!


Shalom Jacobovitz (photographer). 2010 Mavericks Competition.