Harmony

Although in everyday language, harmony usually means notes that sound good together (as in harmonious), this is not a true definition. Technically, harmony is two or more pitches sounding simultaneously. To our ears, concordant sounds—a combination of pitches that we think go together well—are referred to as consonant. On the other hand, discordant ones—pitches that sound as though they clash—are called dissonant. Consonant harmonies tend to provide a feeling of stability and rest, as in the Kyrie from the Pope Marcellus Mass by Giovanni da Palestrina. In contrast, dissonance creates a feeling of instability and the necessity for resolution. This passage from "The Ride of the Valkyries" by Richard Wagner demonstrates how dissonant harmonies create tension and instability.

consonant harmony

dissonant harmony

Consonance and dissonance change constantly within a piece of music. Dissonance is very important because it creates points of tension without which the music would soon become lifeless and boring.Composers use dissonance to create temporary tension within a series of harmonies or harmonic progressions. This tension is relieved by the resolution of a dissonant harmony into a consonant one. The alternation between consonance and dissonance is what gives music much of its life, structure, and sense of motion.

The relationship between consonance and dissonance has changed throughout music history, and it varies from culture to culture. It is important to remember, however, that consonance and dissonance are meaningful only when used in comparison with one another. Neither type of sound is good or bad; rather, they are simply qualities of the harmonic progressions that accompany a melody.

Harmony is generally present regardless of music style. Rock, pop, classical, jazz, and folk music all have an underlying harmonic foundation. In fact, harmony, or its absence, has a lot to do with the listener's perception of style. Arguably, the only style of Western music in which harmony is not always present in its traditional form is rap music, in which percussive and electronic sound effects and multiple, non-tonal voice lines provide a harmonic support. Individual musical styles have a fairly well-defined set of characteristics that include the type of harmonies used within the style.

To most Western listeners, music without harmony sounds somewhat incomplete. However, this is not the case in all cultures. In  Om, an example of Indian music, there is no harmony in the traditional Western sense of the word. Here the function of harmony, provided by the tamboura drone, is to provide a reference point above which the singers and instrumentalists perform elaborate improvisations and meditation-like doublings of the drone tone.

Om

Function of harmony by tamboura drone

Elaborate improvisations