minor 3rds and sadness

One of the great texts on music and its acoustical properties is Hermann von Helmholtz's Tonempfindungen — "Sensations of Tone." In it, he talks about things in such minutely measured detail that his book, written in the 1850s, was still used as a textbook in audio acoustics into the 1960s. Think about that: that's after the advent of electricity, wax recording, radio, magnetic tape, electronic instruments.

Helmholtz also discussed in some detail the physiological basis of our emotional and affective responses to music: specifically, that the minor third was sadder-sounding than the major third because in a major third the tones have a ratio that's less dissonant. (The major third is 5:4, the minor is 6:5. Ratio can be measured not only with tone generators but also with, for instance, guitar-string lengths.)

Now, a fascinating discovery about these tone-relationships, not just in music but in human speech. In conversation, one of the ways we can tell how a person is feeling is the relationships between the pitches of that person's speech. And guess what? A minor third very effectively communicates sadness. It's unmistakable.

Read the article. And don't forget to listen to the revealing recorded examples.