The musical landscape is shaped by the laws of acoustics, and one such law concerns the principle of resonant overtones. Simply put, we often hear more notes than those being played.

For example, under the right conditions, striking a note on a piano may cause other notes to be audible in varying degrees. The struck note is called the fundamental, and the additional notes we hear are called overtones.

The principle is demonstrated in this video.

Musicians, composers, and arrangers make constant use of overtones. Here’s an illustration of how overtones show up when singers harmonize.

Again, we hear more than we may consciously acknowledge. More notes sound than are being sung.

The phenomenon allows a wide range of musical applications. Tuvan throat singers, for example, employ various vocal techniques that enable one singer to sing multiple notes at once.

While overtones usually hover more lightly in our awareness than the fundamental, under some conditions the overtone can sound more loudly than the fundamental. Many overtones escape our awareness altogether.

It’s important to note that in order to hear overtones, the tones must not be obstructed. For example, had the man in the first video placed a blanket over the piano strings, the resonant effect would effectively have been eliminated.

Likewise, to be perceived, overtones require a certain amount of aural space around them, lest they be crowded out. It’s easy to imagine, for instance, that if the Tuvan singer had been accompanied by a large instrumental ensemble we would miss a large number of the overtones she produced.

All of this means that under the right conditions, we perceive more than what is presented to us, and this carries implications that extend beyond music.

Thank you for reading.