A chord is three or more different notes sounding together. Harmony, in the broadest sense, is the sound of chords. A
Harmony is also the overall practice, or science, of creating chords and chord
Harmony is called, metaphorically, the "vertical" element in music, because on a printed page of music, notes that sound simultaneously are lined up vertically. Melody is the "horizontal" element: as a melody proceeds, the notes follow each other from left to right on the page.
Any given melody may be "harmonized" in different ways. A melody consists of single notes, but each of those notes may fit into a variety of different chords. To harmonize a melody, a composer decides which chord progression will work with the melody most effectively and then "builds" the desired chords by adding notes that will be heard together with the melody notes. These chords are called a "harmonic accompaniment" to the melody. The harmony isn't usually just plugged in after the melody is written, however. More often than not, melodies come to a composer's imagination with at least some of the harmonies already attached. And sometimes it happens entirely the other way around: the idea that first comes to a composer's head is a chord progression, and he or she creates a melody to fit the chords.
In fact, one of the greatest problems in using language to describe music is that we can say or write only one thing at a time, so that when we discuss such things as melody, harmony, and rhythm they sometimes seem like separate, and separable, elements. But they're not. They exist simultaneously. They're part of one another.
There is no melody without rhythm, for example, because the notes of a melody are all measured in time, and are therefore related to one another by duration as well as by pitch. And even when we're just humming a simple melody to ourselves, we somehow "hear" or imagine the harmonies at the same time. (You're not sure? Try listening to a familiar melody with someone playing the "wrong" chords, or even
The instruments on which it's most practical to play chords are keyboard instruments like the piano and organ, where all ten fingers are available to play at the same time, and plucked instruments like the guitar and harp. Composers often write chords for bowed stringed instruments like the violin, viola, cello, and double bass, but in actual performance such chords are usually "broken" into two consecutive parts because the physical arrangement of the strings allows the player to sustain a maximum of only two notes at once. Percussion instruments like the xylophone and the glockenspiel can play chords when the player uses two mallets in each hand, but wind instruments can generally play only one note at a time.
|The NPR® Classical Music Companion: Terms and Concepts from A to Z by Miles Hoffman, published by Houghton Mifflin Company. Copyright © 1997 by Miles Hoffman and National Public Radio. All rights reserved.|