Although our eyes can’t tell, vibrating guitar strings behave as standing waves that set the surrounding air into similar vibrational motion, which produces sound waves that ultimately travel into our eardrums. Unsurprisingly, the frequency (# of vibrations per second) of the vibrating string equals the frequency of the sound waves. Hence, a high frequency vibration produces a high pitch note, while a low frequency vibration produces a low one.
So what determines the frequency of the vibrating guitar string? There are multiple factors. First, a higher mass, in this case the thickness, of the string causes it to vibrate at a lower frequency. Second, raising the tension in the string by tightening the tuning pegs increases its vibrational frequency. Last, a shorter length of the string, achieved by placing a finger on particular frets, also indirectly increases the frequency by raising the tension.
Follow the URL below to check out a cool YouTube video captured through an iPhone that shows the wave properties of vibrating guitar strings:
Post written by Justin Han.