A great way to alter a dominant harmony in jazz is to use the diminished full-tone scale. This scale is a combination of a diminished scale and a full tone scale. The scale is detailed: 1/2 integer 1/2 integer integer integer (steps). Notice that the first half of the scale is diminished and the second half is full tone.
There is a much simpler way to form this scale. Actually, the diminished full-tone scale is the melodic minor seventh mode. First, let’s take a look at all of our minor scales. We define the minor sound as having a b3. Remember the sixth mode: wind. This is another name for Natural Minor. If I compare a natural minor scale with a major scale, the spelling is: 1 2 b3 4 5 b6 b7 8. (We call it b3 b6 and b7). The natural minor has two different variations. The first variation is called Harmonic Minor. Compared to major, it is written: 1 2 b3 4 5 b6 7 8. (We call it b3 b6) The second variation is called Melodic minor. It is written: 1 2 b3 4 5 6 7 8. (We call it b3). It should also be noted that the melodic minor scale is b3 on the way up, and on the way down it changes back to a natural minor (b3 b6 b7). We only care about the way UP. The other minor scale we have is Dorian, which is written: 1 2 b3 4 5 6 b7 8. (We call this b3 b7).
I mentioned that it is the seventh minor melodic mode. Let’s look at a melodic C minor scale. CD Eb FGAB C. If we look at the seventh note (B) and go up 1/2 step (to C) we can find out the key in which we are playing. This is the exact same method that we use to play modes based on a larger scale. A diminished full-tone scale actually starts on the seventh note of a melodic minor, then goes to the eighth note (or the first note) and continues to play until I return to the seventh note. The entire diminished pitch of B is played like this: start at B, then go up 1/2 step (to C), and now play C minor melodic.
Bottom line: to form a full pitch lowered, start with the note (whatever you’re trying to play with the full pitch lowered), go up 1/2 step, and follow the minor melodic. Let’s say I want to play a full-tone scale diminished from F #. I start at F #, go 1/2 step up to G, and now I play G minor melodic. (Remember that the melodic minor is actually a major scale with b3). Here is the full diminished pitch of F #: F # GA Bb CDEF #. The chord symbol for a diminished full-tone scale is G7 # 9. It may also appear as: G7alt. Another name it goes by is the Super Locrian. The actual chord contains a b7 # 9, b9, # 4 and # 5. The basic chord compared to the major is written: 1 3 # 5 b7 # 9. This is a very tight chord. It offers a lot of tension and a great release when worn. As with the other altered dominants, we can substitute this dominant for another if we want to add tension. Chords D-7 G7 Cmaj, can be changed to D-7 G7 # 9 Cmaj. This can be done as long as the dominant resolves a 4th to I chord.