Wednesday, November 24, 2010

half/whole vs. whole/half diminished scales

Q: Hi Chris, Just getting into diminished substitutions. I've been using whole/half diminished scales over the diminished subs for the V chord the ii V7 I7. progression. I've been substituting diminished chords on the b9, 3rd, 5th and b7th of the V, usually using the whole/half diminished scale over these diminished subs for the V chord. My ear (and recorded tracks from Jamie Aebersol) tells me that it works well, but in reading various sites, many suggest a half/whole diminished scale. Is it the same function? Can I substitute the half/whole diminished scale over the same diminished chord subs over the dominant? Which one is better, the half/whole diminished scale or the whole/half diminished scale over these dim7 subs? Clarification would help..Thanks

A: First of all, you have to remember, one dim7 chord is really four. So when you say that you sub a dim7 chord on the 3, 5, b7 and b9 of a functioning dominant chord, you are really doing the same one thing. (If we were to use G7 as our example) every one of the subs, creates a 7b9 chord because all four dim7 chords are built from B, D, F and Ab notes, the 3rd, 5th, b7th and b9th of G. The standard way of thinking is "sub a dim7 on the 3rd of a functioning dominant chord." If you prefer to think "sub a dim7 on the 3rd, 5th, b7th and 9th of a functioning dominant chord," it is OK, although keep in mind, it is all the same thing.

Next point: you are right to think that the whole/half diminished scale can work for all these four subs, but once again, just like the four dim7 chords, being a symmetrical scale, all four scales are the same one scale as well. That's right, a B, D, F and Ab whole/half diminished scale all have the same notes and are technically the same scale, same as the four dim7 chords (augmented triads are also symmetrical chords). The other symmetrical scale is the whole tone scale (all whole steps).

It might seem confusing but these four chords and four scales all really being the same thing means that any one and all of the scales work over any four and all of the chords. For example a B whole/half diminished scale played over a Ddim7 chord is the same as, let's say a F whole/half diminished scale played over a Abdim7 chord. Not to be redundant, but they are all the same and if you notated everything and looked at the notes, you would see that they are.

Half/whole diminished scale - Now this is where you might have gotten confused. The half/whole diminished scale is one of the standard choices for a functioning dominant chord, especially one with a b9. But you play it on the root. So a G half/whole diminished scale on a G7b9 chord. BUT, a G half/whole diminished scale is the same as a B, D, F and Ab whole/half diminished scale. So the final result is that you are doing the same things.

Other than the half/whole diminished scale, the altered sub is also popular. It is called the b5sub and you just sub a dominant chord a tritone away. So a G7 chord gets turned into a Db7 chord, and you play a Db lydian dominant scale (which is the same as a G altered scale from melodic minor).


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