Watch the Altered online guitar lesson by Chris Buono from Modes That Matter
This next mode is the second of the two modes we’re looking into that are built from the melodic minor system. The altered scale, also known as super Locrian or diminished wholetone, is built from the 7th degree of melodic minor and it is one that sets its own rules in regards to formula. So far all formulae we have examined thus far have been heptatonic and each sequential degree has been present. Simply put, there’s been seven notes with no skips. Well, that’s about to change for this puppy.
The altered scale is spelled like this: 1 b9 #9 3 b5 #5 b7. Now, you might be saying to yourself “huh?” and that’s fair. As I hinted this scale walks its own path. Let’s look back at the Locrian mode’s formula (1 b2 b3 4 b5 b6 b7) that was doled out in the text for Lydian b7. It’s basically every degree lowered with the exception of the 4th. Looking at one of the alternative names for the altered scale, super Locrian, the formula for the 7th mode of melodic minor could be spelled 1 b2 b3 b4 b5 b6 b7. The problem is twofold: There’s no musical purpose for a b4 (just seeing it in text form is weird!) and it doesn’t do the sound justice. A b4 is enharmonically a major 3rd, which has immense purpose in music. So much so it negates the possibility of its musical opposite. That said, that note is identified as a 3rd making this scale a dominant type since there’s also b7th degree. That leaves that b3 degree to deal with. That is heard as a b2 tension, which is commonly identified as it’s octave extension, b9. As for the dual altered fifths you could also name those degrees as #11 and b13, which are altered extensions of the 4th and 6th degrees. But, then there’s no 5ths in the formula! Fine, do this: 1 b9 #9 3 b5/#11 #5/b13 b7.
With that malarkey out of the way let’s see where these dual tritones are. You have the first one between 3-b7, which is the crucial one in terms of being a V7 chord application, and you will find the next one a whole step above between b5/#11-1. Told ya this scale writes its own rules!