Global Bass Online August/September 2001
By: Lucas Pickford
In my last few columns we’ve looked closely at the
Symmetric Diminished Scales (SDS) and how they can be applied over dominant
seventh chords. Another scale that is very useful over dominant chords is
the one called the Altered Dominant Scale (ADS). The ADS looks like this:
The ADS is different by only one note from
its SDS counterpart but that one note is very crucial in determining when to use
it. The note that is different is the 13th degree of the scale.
The 13th is also referred to as the 6th degree of a scale
but when you extend the scale up beyond one octave, the 6th degree
becomes the 13th degree. In a SDS, the 13th degree
is natural. A SDS starting on C would look like this: C-Db-Eb-E-F#-G-A-Bb-C.
Notice that the A note is natural. In an ADS, the 13th degree is flatted so the A becomes Ab. What’s the big deal if the scale is only different by one note? It’s a big deal because you use the ADS when the harmony indicates a II-V-I chord progression going to minor. The 13th degree of the scale you use on the dominant chord becomes the 3rd degree of the scale of the I chord.
Ex.1- In a common II-V-I progression such as Gmi7 – C7 – Fmaj7, the A note (which is in the SDS scale we would use over the C7, it’s the natural 13th) becomes the 3rd of the Fmaj7 chord. A is the third note in an F major scale. Make sense?
Ex. 2 – In a II-V-I progression that ends up on a minor chord such as Gmin(b5) – C7(b13)- Fmin7, we must anticipate the harmony of the Fmin7 by playing the flat 13th in the scale right before it which is the ADS played over the C7(b13) chord. That Ab note makes the ear hear that the I chord is going to be minor in tonality.
This all might seem like it’s very intricate and to some degree it is, but the main thing to remember is that when the chord progression is heading towards major, like in Ex1, play the SDS. When it’s heading toward minor like in Ex.2, play the ADS. Of course you can break these rules as all good improvisers do but please learn the rules first, then break them. The ADS fits any dominant chord but it is not symmetrical like the SDS. Use it in place of the SDS in the appropriate places. More on this and all things having to do with scales in the next issue.
Copyright © 2000-2009 Global Bass Online