This Is Your Brain on Music: The Science of a Human Obsession

by Daniel J. Levitin

When you hear a saxophone playing a tone with a fundamental frequency of 220 Hz, you are actually hearing many tones, not just one. The other tones you hear are integer multiples of the fundamental: 440, 660, 880, 1100, 1320, 1540, etc. These different tones—the overtones—have different intensities, and so we hear them as having different loudnesses. The particular pattern of loudnesses for these tones is distinctive of the saxophone, and they are what give rise to its unique tonal color, its unique sound—its timbre. A violin playing the same written note (220 Hz) will have overtones at the same frequencies, but the pattern of how loud each one is with respect to the others will be different. Indeed, for each instrument, there exists a unique pattern of overtones. For one instrument, the second overtone might be louder than in another, while the fifth overtone might be softer. Virtually all of the tonal variation we hear—the quality that gives a trumpet its trumpetiness and that gives a piano its pianoness—comes from the unique way in which the loudnesses of the overtones are distributed.