c# minor Rach prelude, what's up with this D7 chord?

[Bob]

c# minor tonic, G# dom 7

what's with the D7 (actually I think it's spelled D, F#, A, B#)?



I'm dying to know.   I don't have the music in front of me, but I think this is accurate.


Is this "D7" some sort of tritone subsition (or combination) with the G#7?  Just another way of prolonging things and making it interesting?  The two chords share the B# and F# tritone...   kind of a tritone prolongation maybe?


lol... dying to know, but too lazy to do a search.... Anyone have any ideas on this?

[fnork]

what's so strange with that? It sounds good, and it's not that unusual anyway... An example of it from the top of my head is Dvoraks Dumky trio, second movement, at the end of the first fart part, just before the cello cadenza.

Go to a piano, and play with your left hand Eb, G and Db - that makes a Eb7 chord without fifth, right? And now play with your right hand E (a small third after the Db in your left hand), A and C#. That makes an A chord, right? Here, you also have the tritone thing, but instead of playing one chord after another, you play both of them simultaneusly. This chord is often used in jazz, and actually it's just an Eb7 chord with some nice colourings (-9, +11), which usually leads to some kind of Ab minor chord.

Sounds good, doesn't it? As you see, it's just an Eb7 chord which naturally leads to Ab. I think that the D7 in the rachmaninov piece leads very naturally to the G#, in the same way.

[Daevren]

D7 is a tritone sub for G#7