[Smt-talk] Rachmaninoff-Subdominant-Strauss-Dominant

[Ninov, Dimitar N]

Dear Ildar,

The point that you bring up with the so-called Rachmaninoff's Subdominant is very interesting, and depending on different contexts, it could be interpreted as a plagal or authentic relation to the tonic, or both. I have been interested in altered chords for quite a while, so let me offer a few schematic examples.

1. F-Ab-B-D# as an altered VII chord which resolves into I6 with a doubled third. A famous example is one of the harmonizations of the main motif/phrase in Till Oilenshpiegel by R. Strauss (the excerpt is in F major, thought, the chord being Bb-Db-E-G#). Origin: VII diminished seventh chord with a raised third in a major key - VII dim7 (#3). Of course, in this particular context the chord is inverted and presented as VII dim4/3 (#3). This label is a combination of figured bass and a number which refers to the root of the tonic. An interesting feature is the enharmonic equality of this chord with the half-diminished seventh chord - something that could be used in enharmonic modulations.

2. F-Ab-B-D# as an upper extension of an altered V9 chord. This is one of the most popular altered dominants in jazz, namely V7 (#5 b9) or V7+5-9 as Joe Pass would label it. Of course, the root G is omitted.

As VII7  is an upper extension of V9, so No. 2 incorporates No. 1. This Strauss's dominant  may also resolve into a minor tonic (the D# becoming an Eb), and then we may label it as V7 (b13 b9). With exactly the same label, we may still resolve  into a major tonic, but this time the flat 13th will resolve down to a tonic 9th, instead of upward into a tonic 3rd. as in V7 (#5 b9).

I do agree that if you resolve that chord with a leap of a perfect fourth downward to the tonic root, it will be at least half-plagal and half-authentic, just as F13#11 resolved into C. In this latter case, the plagal elements are even stronger given the tight  F7 arrangement on which the upper tones are superimposed. F 13#11 may also resolve into a minor tonic chord, considered as an altered subdominant in melodic minor.

A joke: these chords contain an augmented sixth; shall we invent a geographic name for them? Perhaps "Portuguese +6" or "Japanese+6"? I just learned that there was a "Russian +6" 

Best regards,

Dimitar

Dr. Dimitar Ninov, Lecturer
School of Music
Texas State University
601 University Drive
San Marcos, Texas 78666