Dr. Justin Henry Rubin © 2005
Polytonality is a catchall theoretical term that can be applied to a multiplicity of musical concepts that need to be examined individually.
Composers such as the American Charles Ives (1874-1954) write works that consist of strata of primarily diatonic parts, just each in a different key. This juxtaposition of two or more keys (or modes) can be used in denser texture as a way to draw clear lines of delineation between significantly contrasting material. However, when the substance of the music is more unified, the implementation of varying keys can be used to create a unique blending of harmonies.
Alternatively, composers such as Kaikhosru Shapurji Sorabji (1892-1988), freely draw from a triadically based vocabulary that does not necessarily relate to any single tonality. These chords and scalar materials can sound in succession and/or simultaneously to create unique and expressive sonorities.
A more systematic technique, planing (which is often associated with the so-called Impressionistic School of composition) involves articulating a series of chords of identical quality but with different roots. Although the scale from which the basic melody is derived can lie within one tonality, the displacement resulting from the accompanying chord qualities, which by definition will contain chromaticism in direct conflict with the underlying key, will suppress the functionality associated with those scale degrees.
A. Bitonal Composition
B. Polychordal Composition
AUDIO and MIDI files can be listened to on this page or downloaded separately here.
A. Bitonal Composition
Developing Compatible Keys in a Polytonal Composition. When working with two keys simultaneously, the composer must decide how they will complement one another (if they should, in fact) as well as how their characters will be exploited when in conjunction. In the following piece for guitar, we will establish two clearly distinct key regions: g minor and e minor. These keys can complement one another in that they share many pitches, however the critical third of g minor (Bb) will create tension with the dominant of e minor (B natural) and the tonic of e minor is in complete conflict with the sub-mediant of g minor (Eb).
To bring clarity to the situation, the keys will be separated first in terms of register, with g minor restricted to the lower tessitura, functioning as an accompaniment to the treble melody in e minor. Secondly, they will be expressed in contrasting rhythmic strata, with the triple time accompaniment guiding the meter in which the duple time melody will be articulated. In this way the metrical layout will be complementary similarly to the juxtaposition of the keys.
The piece is laid out in four distinct sections with a brief coda. The introduction establishes for the listener a simple accompanimental figuration unambiguously in g minor. This allows the contrast that is established with the sudden commencement of the melody in e minor in section A to be more significant.
Section B introduces some brief chromaticism into the two key regions, which is, ironically, the same sounding note (Db/C#) in each. As well, the climactic notes of the whole composition occur here.
Section C brings back the purely diatonic ideas of A but with the melody reaching into a lower register, thus bringing the two keys into their closest spacing.
The Coda finds a middle ground between the two keys, perhaps leaning a bit towards the accompaniment, in order to facilitate a persuasive sounding cadence. As well, the C# of the middle section is reasserted as a concluding bond.
mp3 download (guitar recording by Andrew Hull)
Continue for a contrasting application of polytonal ideas.
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