The harmonic series is a naturally occurring, acoustic phenomenon. When a body vibrates, like a string on a violin or a column of air in a flute, a complex, regular and predictable series of pitches are produced. Scientist call the lowest pitch, the fundamental; this starting point for the sound can be any frequency. However, the fundamental does not vibrate in just 2 dimensions, it vibrates in three dimensions, causing a predictable series of overtones to vibrate as well. These overtones occur at simple multiples of the fundamental frequency: 2x, 3x, 4x, 5x, etc….

For example, start with a frequency of 100 Hz. As a body vibrates at 100Hz, it will cause other vibrations in the simple series we have seen: 200 Hz, 300 Hz, 400 Hz, 500Hz, ect…. When we compare the fundamental to another one of these sounds we can express that relationship as a ratio, 2:1, 3:1, 4:1, 5:1.

Viewed as a simple, linear, evenly spaced series of ratios, the Harmonic Series provides the naturally occurring, physical basis for the sounds we hear, and, consequently, for much of the music we have made in the history of humans around the globe. This is especially true of singing and music played on wind and fretless stringed instruments.

However, music based on the Harmonic Series, is just one method of making music. We´ll be exploring other systems in coming blog posts.