[Smt-talk] BELGIAN +6

[Dmitri Tymoczko]

I am confused by this discussion of augmented sixths.

I believe that Stephen Jablonsky is talking about the chord (in C major) Ab-C-E-F#, which starts life as an F# half-diminished but, upon acquiring a lowered third, becomes a (sounding) "augmented triad with a minor seventh."  It's a pretty rare chord because the two common tones weaken the resolution to I6/4, while the E->D weakens the resolution to V.  So it's not obviously superior to the more standard forms.

I believe that Walt Everett's "Levittown Sixth" is (in C major) F#-A-C-E, which is a (sounding) half-diminished chord, acting as an "augmented sixth-type" dominant of F-A-C-F.  (If so, a variant of the chord appears at the end of Tristan, where F-Ab-B-D# resolves to E minor; I also dimly recall an appearance of the actual resolution somewhere in Brahms ...)  Perhaps the chord started life as bII7 of IV, but acquired a lowered third and fifth.  (Who knows?)

Am I wrong?

The reason for considering the "Tristan chord" to be an actual chord, rather than a "mere agglomeration of nonharmonic tones," is that throughout the opera, purportedly nonharmonic tones conspire to produce a sounding half-diminished seventh chord, and do so in an uncountable variety of ways.  One wants to account for this consistency.  Furthermore, and perhaps even more importantly, the "Tristan" voice leading is very clearly derived (via voice exchange) from a more basic template (F, Ab, B, D#)->(E, G#, B, D) which appears throughout the opera.  One wants to be able to relate the initial version with the voice exchange to the later versions without the voice exchange, as well as being able to observe that the voice exchange is a pervasive feature of the opera.  

DT

Dmitri Tymoczko
Associate Professor of Music
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