Traditional sub-Saharan African harmony is a music theory of harmony in sub-Saharan African music based on the principles of homophonic parallelism (chords based around a leading melody that follow its rhythm and contour), homophonic polyphony (independent parts moving together), counter-melody (secondary melody) and ostinato-variation (variations based on a repeated theme). Polyphony (contrapuntal and ostinato variation) is common in African music and heterophony (the voices move at different times) is a common technique as well. Although these principles of traditional African music are of Pan-African validity, the degree to which they are used in one area over another (or in the same community) varies. Specific techniques that are used to generate harmony in Africa are the "span process", "pedal notes" (a held note, typically in the bass, around which other parts move), "rhythmic harmony", "harmony by imitation", and "scalar clusters" (see below for explanation of these terms).
General overview
"By Western standards, African music is characteristically complex...Two or more events tend to occur simultaneously within a musical context. Even players of simple solo instruments (such as the musical bow or the flute) manage to manipulate the instrument in such a way to produce simultaneous sounds by playing overtones with the bow, by humming while bowing, and the like...Overlapping choral antiphony and responsorial singing are principal types of African polyphony. Various combinations of ostinato and drone-ostinato, polymelody (mainly two-part), and parallel intervals are additional polyphonic techniques frequently employed. Several types may intermingle within one vocal or instrumental piece, with the resulting choral or orchestral tendency being the stacking of parts or voices. Consequently three- or four-part density is not an uncommon African musical feature. Such densities are constantly fluctuating so that continuous triads throughout an entire piece are uncommon. Canonic imitation may occur in responsorial or antiphonal sections of African music as a result of the repetition of the first phrase or the introduction of new melodic material in the form of a refrain. The latter may involve a contrasting section or a completion of the original melody." —Karlton E. HesterKarlton E. Hester, Bigotry and the Afrocentric “Jazz” Evolution, Third Edition, Global academic publishing, published, April 30, 2004
Chordal relationships that occur as a result of the polyphony, homophonic parallelism and homophonic polyphony found in African music are not always 'functional' in the western musical sense. However, they accomplish the balance of tension-release and dissonance-consonance. In addition, they form varieties of chord combinations and clusters, as well as varying levels of harmonic patterning.
Scales
Chords are constructed from scales. Pentatonic and hexatonic scales are very common scales across Africa. Nonetheless, heptatonic scales can also be found in abundance. Anhemitonic scales, equal heptatonic scales, and scales based on the selected use of partials are used in Africa as well. The same community that may use one set of instruments tuned to a certain scale (i.e. pentatonic), can use a different scale for a different set of instruments, or song type (i.e. heptatonic).
In traditional African music, scales are practised and thought of as descending from top to bottom. African harmony is based on the scales being employed in a particular musical setting. Scales have a profound impact on the harmony because Africans modalize their music. Modalization is the process of applying modal concepts in a non-modal setting. African music uses recurring harmonic reference points as a means of musical organization. Therefore, African music is not modal or purely based on one mode. Nonetheless, modal concepts are employed in African music. This predates exposure to Western and Arab musics.
Principles
Homophonic parallelism and homophonic polyphony
Homophonic parallelism is the harmonizing of a single melody, or subordinate melody and moving with it in parallel. This means the notes that harmonize the melody follow its characteristic shape and rhythm. This type of parallelism is common to all African peoples, but the degree to which it is employed varies. Parallelism in thirds (inversely tenths), fourths, fifths, and octaves (inversely unison) are Pan-African methods of homophonic parallel harmonization. These intervals are interchanged depending on the melody they are accompanying and the scale source of the harmonization.
Homophonic polyphony occurs when two different melodies are harmonized in the style of homophonic parallelism, and either (1) occur simultaneously by means of overlapping antiphony or (2) over at the simultaneously as a result of melodic counterpoint.
This parallelism is not to be confused with strict parallelism. Gerhard Kubik states that much variation and freedom is permitted in parallel parts, with the stipulation that words remain intelligible (or in the case of instruments the melody remains recognizable), and the scalar source is observed. The harmonic line harmonized normally moves by step rarely jumping beyond a fourth.
"A.M. Jones states that 'generally speaking all over the continent south of the Sahara, African harmony is in organum and is sung either in parallel fourths, parallel fifths, parallel octaves or parallel thirds.' Parallelism, however, is not without limitations. Melodic and scale considerations, as has been shown, are of primary importance in deciding what notes are employed in harmonizing tunes and, consequently, what intervals are formed. The adaptation of parallelism to fit melodic requirements is much more apparent in the music of those areas of Africa where the pentatonic scale is the norm. Kirby has shown how the demands of a pentatonic scale result in the employment of sixths in Bantu polyphony, where parallelism in fifths is the principle. He points out that the limitations of the pentatonic scale make for the awareness of other intervals instead of what apparently was the strict duplication of the melody at the same interval employed by early European musicians."—Lazarus EkwemeLazarus Ekwueme, Concepts of African musical theory, Journal of Black Studies, Vol 5. no. 1, Sage publications, inc. published 1974.
Secondary melody
The harmonization of a subordinate melody – be it responsorial or with regular repetitions within the cycle – is often based on a counter melody or secondary melody. From this melody the span process, pedal notes and other techniques can be used to for the harmony supporting the main melody.
Gerhard Kubik notes "In the Ijesha multipart singing style the basic chorus phrase, to which harmonically parallel lines may be added above and below, is the one in the middle, standing at the same pitch level with the leader's phrase...The basic chorus line is the one with which the chorus member singing alone would invariably link 'in unison' with the leader's phrase. as other chorus members join in, more voices are then added above and below in intervals perceived as consonant. These additional voices are essentially euphoric in concept; they are equivalent to a basic one, but are only collaterally dependent on the voice of the leader".
Lazarus Ekweme quotes J. H. Kwabena Nketia saying "In chorus response, there is primacy in the sense that one line is regarded as the basic melody. But the supporting line, by virtue of its running parallel to it, shares its characteristic progressions and is accordingly treated as a secondary melody. Indeed, when a cantor has to sing the chorus response, he may have the freedom of singing either of the two or of moving from one section to the other."
Secondary melody in this case refers to the voice harmonizing the chorus response. However, the chorus response is the secondary melody, which is harmonized. The harmonizing parts can vary just as the chorus response (or secondary melody) may vary. The added harmony part embellishes its own line as an independent melody, instead of following rigidly the intervocalic distance from the main chorus line in parallel movement.
The underlying concept is to create a melody and then a responsoral secondary melody. This secondary melodic line or phrase is then harmonized in parallel motion. The harmonic line harmonized normally moves by step rarely jumping beyond a fourth.
Ostinato-variation
Musical instruments in traditional African music often serve as a modal and/or rhythmic support for vocal music. Instrumental Music can also be heard frequently without vocal music and to a lesser extent solo. Harmony produced through ostinato produced on instruments is common place. These ostinati can be varied, or embellished, but otherwise provide modal support. Ostinato used in African music is a principal means of polyphony although other procedures for producing polyphony exist. Arom Simha states "music in the Central African Republic, regardless of the kind of polyphony or polyrhythm that is practiced, always involves the principle of ostinato with variations."Simha Arom, African Polyphony and Polyrhythm. Structure and Methodology (Préface de Györgi Ligeti), Cambridge, Cambridge University Press, published 2004 .
The principle of ostinato with variations is significant to African music and its polyphonic nature as most forms of traditional African polyphony are based on this principle. Simha continues "If one had to describe in a formula all the polyphonic and polyrhythmic procedures used in the Central African Republic, one might define them as ostinato (ostinati) with variations." The ostinato is normally used to create a modal pattern or background.
Arom Simha continues "This definition does not conflict with Western musicological definitions of the term. Thus Riemann defines ostinato as 'a technical term that describes the continual return of a theme surrounded by ever changing counterpoint [...] The great masters of the age of polyphony loved to write a whole mass or long motets on a single phrase constantly repeated by the tenor. But the repetitions are not always identical, and the little theme would appear in all sorts of modified forms' (Riemann 1931:953)."
Many African musics correspond exactly to this definition and are musical pieces based on a phrase, which reappears in varied and modified forms. These ostinato can be continuous or intermittent, vocal or instrumental, and may appear above or below the main line. Frequently in African music two or more ostinatos moving contrapuntally are employed, with or without a longer melodic line to create an orchestral texture (dense textures are desired and aimed for by both composers and performers alike). This type of polyphony is of the contrapuntal or horizontal type. In practice each ostinato moves in independent melodic and rhythmic patterns.
Cadences and chord structures
Chords are normally formed using one of two techniques: the span process or scalar clusters. These chords can be embellished as a result of variation in which any combination of notes permitted by the scale can be used in a chord. However, in common practice, chords are formed by harmonizing in 3rds, 4ths, 5ths, 6ths, etc. The type of chord formed depends on the scale system being used.
Recent research has shown that African music has chord progressions. Gerhard Kubik states "until recently, little attention has been paid to a further structuring element, namely, the tonal-harmonic segmentation of a cycle. In most African music, cycles are sub-divided into two, four or eight tonal-harmonic segments." (A theory of African music, Volume II, page 44, paragraph 5).