Tuesday, 5 May 2009

Chord Soup: a study in quartal harmony based on Skriabin's "Mystic Chord"

Chord Soup is a miniature piece for string sextet or string chamber orchestra (v,v,v,vla,vc,db). It was only ever planned as a short pre-study to my larger piece, Reconciliation. I had therefore never envisaged Chord Soup for public consumption, but had always harboured a secret soft-spot for it. Many months later, I went back and stirred it up a little... 

 Connect your device to a decent sound system or enclosed headphones, and click the orange PLAY button...

Alternatively, you could listen to the music at its URL:
If you wish, you can read the score (as a pdf file) here.
This link will open in a new window so you can follow the score while listening.  Both the score and the mp3 recording are free and downloadable.
Back when I first sketched Chord Soup, I was experimenting with its key ingredient, Skriabin’s ‘Mystic Chord’, excitedly tasting its characteristic flavours:
Read more about this chord at wikipedia.
This chord is ‘non-functional’ in a conventional harmonic sense because it is Quartal, ie., it uses chords stacked in fourths instead of thirds. It is not unlike a mini-"skyscraper" chord, a thick, opaque chunk of sound. Presented in this manner, like a pinned insect specimen under glass, it looks (and sounds) like an inert and immovable object. After all, it uses up a full six of the twelve possible notes, whereas a "normal" chord requires only 3 or 4, or possibly 5 when 'extended' (eg, G, G7, or G9).
Crucially, the Mystic Chord lacks a perfect fifth above its root (in this case there is no D above the G). This denies the chord a clear tonal axis, thus is a big factor in the ambiguity I so enjoy. But it is a moot point as to whether there is an identifiable "root" note at all ...ah, but I digress.
Just like traditional tertian chords, the Mystic Chord (a.k.a. the "Prometheus Chord") can be arrayed in various dispositions, plus be inverted as well. Given that there are 6 notes available instead of the usual 3 or 4, simple arithmetic suggests that the number of possible voicings and inversions offers the composer a considerably larger number of options and (therefore) a much wider spectrum of harmonic colours and degrees of tension.
Herewith a few examples, from which one can extrapolate:
The quartal harmony born of Skryabin's chord therefore admits not only of fourths but a wide variety of intervals - even (gasp!) thirds and fifths. However, it lends itself most readily to a harmonic language favouring seconds, fourths, sevenths and ninths, thereby casting doubt on the assumed distinction between 'consonance' and 'dissonance' so smugly (and arbitrarily) asserted by conventional chord structures like C, G7, f#m, etc.
Like tertian chords, Skryiabin's Mystic Chord can also be transposed through all 11 of the other semitones, eg., here I've transposed up it by a perfect fifth:
Given the assumption that "bass notes = root notes", Chord Soup can be reduced (in terms of Shenkerian Analysis) to the very simplest chord progression I - V - I, the simplest of tonic prolongations, plus a short formulaic coda (complete with traditional octave leaps circling in on the tonic at the end of bar 13):
This is, in effect, forcing Quartal Harmony (innately non-functional materials) into the straightjacket of functional traditional tonal conventions. It's rather like trying to mix oil into water: well, as they say, Impossible is Nothing. However, the ear can quickly reconcile the conflict precisely because the formal context is so familiar and unambiguous. It is also on an extremely compressed time-scale (only 15 bars or 56" long), thereby demanding precious little of the listener's musical memory. In short, the dilemma exists primarily on paper and in the Theorist's mind, not so much in the ear of the Listener.
In fact, even the unsuspecting listener soon hears and accepts the quartal chord on G functioning in the role of Tonic, and the quartal chord on D functioning as in the role of Dominant. The usual principles of perceived consonance and dissonance apply just as much here as they do in Mozart or Mahler - the quartal chord on D is heard as "the dominant" precisely because it has been placed in a position conventionally heard as relatively unstable. It's the "B" in the old "ABA" paradigm.
The "arch form" of the first violin's melody also facilitates this perception of Tonic-Dominant polarity. The violin melody surges up in waves to the high point at bar 5, and so does the bass, at which time the harmony changes to chord V. From that point it reverses direction and begins falling in similar waves until the return to chord I at bar 9. Likewise, the bass rises and falls to assist the ear to articulate these pivotal structural moments. The violin and the bass are therefore not just pretty faces, but actively serve to highlight the harmonic architecture of the entire piece.
And just like all "normal" tonal I - V progressions from Machaut to Madonna, there is even a "common note". In fact, the composer exploiting the intriguing resources of Skryabine's Mystic Chord happily discovers the luxury of a choice between two common notes (in this piece, the notes E and B). Listen, for instance, to the note E in the first violin during bars 4 and 5 as the harmony underneath changes from I to V.

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