Contents |
Melody, which is a succession of single sounds, is the basis of harmony, although it is essentially distinct from it. Music to be performed by one voice or by an instrument which is capable of giving but one tone at a time is written as a melody. As the voice or any of these solo instruments, as they are called, are rarely heard alone, being generally accompanied by other instruments, the compositions in which they occur are usually written in harmony, that is two or more different musical sounds at different pitches are produced simultaneously, and melody pure and unaccompanied is little heard. In fact, the impression has grown that melody without harmony does not exist. Nevertheless melody was the only form of composition in existence for thousands of years and it still exists as the sole form known to many nations of the East. Their melodies are perhaps not tuneful to our ears, but according to the scales and to the aesthetic sense of the people to whom they belong the music fulfils all the requirements of the melody .The most simple form by which the effect of harmony is produced is in two sounds taken together. Among these combinations are some which please the ear and others which are less agreeable. They are known as consonances and dissonances, respectively.
Just as those harmonies situated nearest to the fundamental possess more consonance with it than do those farther away, the simultaneous combinations of octaves, fifths and fourths possess greater consonance, for these are the harmonies possessing the simplest ratios with the fundamental. They are not the smallest intervals by any means but their consonance rests upon the simplicity of their ratios. The ratio of the ideal consonant interval is as 1 is to 1 which, of course, is a unison and it is only logical that those tones bearing the next simplest relations would possess the next greatest consonance. Musicians have established arbitrary decisions as to the consonance and dissonance of certain intervals and in the discussion of harmony it is necessary to recognize the distinction thus determined upon. Those intervals whose ratios are expressed by any of the figures from one to six are consonances, all others except those that are merely a former interval doubled as 2:6, 1 :12, 4:8, 6 :12, etc., are dissonances. The tables of consonances and dissonances read thus:
The root of a chord is easily described as the first, third and fifth note :
Source: http://www.harmony-central.com/Guitar/harmonics.html
The natural frequencies of the string are determined by the ends of the string, which can't move. When you play a harmonic, you very gently hold you finger against the string at some other point. You have added a third point along the string that can't move. Now, the only frequencies that can exist must have nodes at this point, as well as at the ends of the string. That's really all there is to it
Barbershop harmony, as codified during the barbershop revival era (1940s-present), is a style of a cappella, or unaccompanied vocal music characterized by consonant four-part chords for every melody note in a predominantly homophonic texture. Each of the four parts has its own role: generally, the lead sings the melody, the tenor harmonizes above the melody, the bass sings the lowest harmonizing notes, and the baritone completes the chord. The melody is not usually sung by the tenor or bass, except for an infrequent note or two to avoid awkward voice leading, in tags or codas, or when some appropriate embellishing effect can be created. Occasional brief passages may be sung by fewer than four voice parts.
See http://www.outsideshore.com/school/music/almanac/html/Music_Theory/Harmony/Other_Chord_Types.htm