Omnibus progression

From Wikipedia, the free encyclopedia

The omnibus progression is a harmonic sequence that is primarily characterized by chromatic lines moving in opposite directions. Examples in music include Schubert's Piano Sonata in A minor, Op. 42, first movement, mm. 32-39, and Brahms' Opus 116, No. 3. Although Paula Telesco has established that it has its origins in the various Baroque harmonizations of the "lament bass," the origin of the term "omnibus" to describe this particular sequence is unclear.

The progression can feature a fully chromatic descending octave in the bass, and chromatic ascending tetrachords in the soprano, tenor and alto and again finally soprano to complete the structure, although other voicings are quite possible.

[edit] Chords

All or part of this article may be confusing or unclear.
Please help clarify the article. Suggestions may be on the talk page. (August 2007)

In the following example, the omnibus expands Dominant harmony (in C minor) first by filling the space between the leading tone and the dominant in the bass with chromatic passing tones, then by putting a unique chord above each of those bass notes. To complete the omnibus' identity, an upper voice would move chromatically in the opposite direction, from the dominant note up to the leading tone, and on to the tonic.^[1]

| Cm | G7(6/5) | Bb7 | Dm(6/4) | Bb7(4/2) | G7 | Cm |

A more complete expression of the omnibus would be as follows:

| Cm | G7(6/5) | Bb7 | Dm(6/4) | Bb7(4/2) | G7 | Bm(6/4) | G7(4/2) | E7 | G#m(6/4) | E7(4/2) | C#7 | Fm(6/4) | C#7(4/2) | Bb7 | Dm(6/4) | Bb7(4/2) | G7 | Cm |

In this example the brackets indicate complete rotations of the three harmonies that make up the omnibus pattern. The sequence effectively divides the octave into 4 equal parts, labelled A through D. After four rotations the sequence automatically returns to the chords of the original rotation, one octave lower, noted with the reappearance at the second 'A'. For the purposes of composition, the pattern may be halted at any point in the sequence, facilitating modulation to keys other than the original.

[edit] Notes

^ In these examples the chord name and quality is given, followed where necessary by brackets containing the inversion in figured bass terms. For example, 'Cm(6/4)' refers to a C minor triad in second inversion. Chord names are enharmonic equivalents where it is convenient to spell them that way.

[edit] References

Gauldin, Robert. "The Theory and Practice of Chromatic Wedge Progressions in Romantic Music." Music Theory Spectrum, Vol. 26, No. 1. (Spring, 2004), pp. 1-22.
Kostka, Stefan, and Dorothy Payne. Tonal Harmony. 6th edition. New York: McGraw-Hill, 2009. (Pp. 476-480)
Laitz, Steven G. The Complete Musician. 2nd edition. New York: Oxford University Press, 2008. (Pp. 845-846)
Telesco, Paula. "Enharmonicism and the Omnibus Progression in Classical-Era Music." Music Theory Spectrum, Vol. 20, No. 2. (Autumn, 1998), pp. 242-279.