Harmony

Transcript

In common usage, the word harmony refers to the emotionally positive experience of hearing and performing simultaneous tones in music. When one hears two or more simultaneous tones, some combinations blend well whereas others seem to clash with each other. The sense of harmony depends on the intervals among the tones; the sonority tends to be perceived as more harmonious or consonant if all of the individual intervals in the sonority are themselves more consonant. Harmony has been a characteristic element of Western tonal music since the first notated vocal polyphony (Notre Dame, Paris, late 12th to early 13th century). The word harmony is also used to describe chord progressions and theories of writing them.

Harmony is just one of a series of positively connotated terms for the positive experience of hearing simultaneous tones in music. Other terms include consonance, euphony, concord, and sonority. Music theorists sometimes refer to harmony as the “vertical” aspect of musical structure, since in conventional music notation harmonies are written vertically, whereas melody, rhythm, voice leading, chord progression, modulation, and form are horizontal aspects.

Harmony is an integral element of Western and many other musics. It is what one experiences when simultaneous tones blend smoothly in the perception to create a new perceptual whole, often called a chord. Harmony is a kind of added value: the positive experience of listening to a harmonious sonority is somehow greater than the sum of the positive experience (if any) of listening to the tones that make it up (each one in isolation)—suggesting that general gestalt principles may help in the understanding of harmony's nature and origin. Similarly, the negative experience of discord (or dissonance) can be greater than the sum of the negative experience (if any) of the isolated tones that make it up.

The Perception of Harmonic-Complex Tones

Why should one tone combination sound harmonious while another tone combination sounds dissonant? Since Jean-Philippe Rameau wrote his seminal music-theoretical treatises in the early 18th century, most scholars believe the answer [Page 530]lies in the acoustic structure of individual tones and the perceptual processes that allow people to make sense of these structures. The same principles that explain the perception of individual tones in speech (voiced speech sounds) can be applied to the perception of musical tone simultaneities.

Charles Kelley, Hillary Scott, and Dave Haywood of Lady Antebellum provide the harmony vocals at the Keith Urban concert in the Air Canada Centre, Toronto, Ontario, October 3, 2009. In common usage, the word harmony refers to the emotionally positive experience of hearing and performing simultaneous tones in music.

Like most musical tones, voiced speech sounds such as /a/ or /n/ have periodic waveforms. According to Joseph Fourier's theorem in mathematics, this means that the collection of pure-tone components that make up these periodic waveforms—their spectra—are harmonic. These tones are therefore called “harmonic-complex tones”; they are “complex” because they can be analyzed into several partials or pure-tone components. The frequencies of the partials correspond to a harmonic series in which the intervals between adjacent partials correspond approximately to musical intervals: a perfect octave (P8) between harmonics 1 and 2, a perfect fifth (P5) between 2 and 3, a P4 between 3 and 4, a major third (M3) between 4 and 5, a minor third (m3) between 5 and 6, then a series of four intervals close to an M2 (each smaller than the last), then a series of m2s.

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