In this tutorial we’re going to dive into the outside sounds of the Whole/Half diminished scale when used over a static minor 7 vamp. This is one of Scott Henderson’s many approaches as set out in his 1988 DVD Jazz Fusion Improvisation (this is still an amazing resource, if you can get hold of it!)
It’s not a very common idea and rarely gets covered in music theory books. Standard music theory thinking tends to favour the W/H Diminished scale over Diminished 7th chords (which hopefully makes total sense!) However, the W/H diminished scale can offer some really cool outside sounds that go way beyond this limited use.
We can look at it as a slight variation to the Dorian scale, which is a really common choice over static m7 chords. Here’s A Dorian:
As the name suggests, the W/H Diminished scale is made up of alternating Whole and Half steps. A diminished is as follows:
As you might see, the only difference between A Dorian and A Diminished is the outside b5, #5 and major 7 notes:
A Dorian:
A Diminished:
A B C D E F# G
A B C D Eb E# F# G#
Of course E# would typically viewed as an F on the guitar – don’t worry too much about the name, it’s the interval name and sound that are important here! Interestingly this scale completely avoids the perfect 5th – one of the intervals that makes us feel at ‘home’ – so the fact that it’s missing also adds to the outside nature of the scale in this context.
A good place to start with this scale is simply viewing its Whole/Half makeup all over the fretboard so we can start to see its symmetrical nature. Here’s A W/H on one string:
It’s also important to memorise the diminished 7th arpeggio itself – not only is this useful for many applications, but it’ll help see how Scott often visualises his lines when improvising. Here’s a simple one octave A dim7 arpeggio:
As you can see, the two outside strings have a symmetrical pattern on guitar. As with ANY diminished pattern, this can be repeated all over the fretboard in minor 3rd (3 fret) intervals.
A key component of Scott’s improvising is visualising this string skipping shape where we miss out the middle string of the dim 7 arpeggio. Here you’ll see that minor 3rd repetition in action:
More importantly, if we dig into this even more, we’ll discover these useful string skipping shapes lurking next to each other:
These super useful and moveable 6ths are also found one fret lower on the 2nd and 4th strings too:
Try this exercise to get your fret hand nice and mobile across the fingerboard. It’s based around the previous two string skipping shapes and will really help to break you out of those closed box shapes:
This brings us to a more musical approach and an idea that Scott (and other players such as Mike Landau) frequently use when improvising. These string skipping shapes naturally create a major 6th interval and they sound great all over the fretboard. In this example we’re descending through these shapes using slides:
This lick neatly brings us into Scott’s outside blues improvising vocabulary where these type of lateral (sideways) and wide intervallic movements are preferred over linear scale runs. Notice that we’re starting in familiar blues territory before launching into the diminished sound in bars 3-4:
Finally, if you’d like to have a go at some of these ideas and more, you can find all the TAB from the YT video and backing track on my support page. Here’s a video with more guidance on these concepts:
