In honor of the passing of one of my most influential guitar heroes, Allan Holdsworth, and perhaps one of the most innovative guitarists of all time, I’d like to look at his use of diminished scales; in particular, the half-whole and the whole-half diminished scales. While you might be frightened off by the uses Allan gave to these scales, rest assured that the essence of his approach is as easy to grasp as it is to implement in your own playing. Let’s dive in…
First Things First
In Allan’s system for improvisation and chord playing, everything is derived from the scale pattern in question. In this guide, we’ll look at two diminished scales: the half-whole, which means that we get a symmetrical sequence of notes starting in a half-step (semi-tone, ST) and alternating with a whole-step (tone, T), which gives us:
ST – T – ST – T – ST – T – ST – T – ST
And the whole-half, which is the same idea starting on a whole-step:
T – ST – T – ST – T – ST – T – ST – T
If you look at this the length of the neck, as Allan would, you can then begin to extract chords. Look at the following neck diagram for the C Half-Whole Diminished Scale and see what chords you can find:
If you zero in on the C at the third fret of the A string, you should be able to make out the following chords: C, Cm, C6, Cm7, Cm13, Cm7b5, C7, C7b9, C7#9, plus a host of others, which means you can play the C Half-Whole Diminished Scale over… pretty much anything!
Obviously, you’re going to a get a fairly outside sound over these chords, or, ‘all the rude notes’, as Allan would say, so you might want to use it sparingly, or not.
Look again at the pattern and you’ll see that it separates into repeating blocks:
I imagine that Allan may have learned the scale this way given his liking of four-note-per string patterns, and he certainly would have had no problem with the stretches, even down at the nut.
If you want to break the pattern down into yet more manageable chunks, notice that it repeats every three frets:
Now, all those chords we found from the C root note also apply to the notes marked above! This is one of the most versatile scales out there, and one of the most overlooked scales by guitarists. The symmetrical nature of the scale also throws into doubt the real root note as any of the above notes could theoretically be the root, but it doesn’t really matter as long as you can pull out the pattern when you need it.
The Whole-Half Diminished Scale
You’re going to love this. Simply shift the half-whole pattern down a fret and you get the whole-half pattern! Here they are together so you can see it.
Imagine the fun you can have with this one! Do bear in mind though that when you shift the whole thing down, the chords you can (technically) play over change. As regards C chords we now have a CmM7b5, C6sus2sus4 (Dm7/C), CM#9sus4, and a host of other Holdsworthian chords. You could also do what Allan did as regards coming up with your own chords by finding groups of (usually 4) notes that you like the sound of and moving these sets of notes up and down the fretboard.
The idea here then is to improvise and experiment as Allan did without thinking too much about the theory of it all. I find the diminished sound very distinctive of his playing, and a very accessible way to add a touch of Holdsworth over pretty much any chord.
READ MORE: The Improvisational Genius of Allan Holdsworth