Today I'm going to talk about a particular scale (or sound) you can apply either in your improvisation or as a composing device. The whole tone is a six note scale with a really unique sound. It's built from whole steps, which gives a super unbalanced sound to this scale.
1. Whole Tone Theory
As I said, constructing this scale means using just pitches a whole step apart. That makes whole tone a scale that lacks of a tone center, and a scale with six note instead of seven.
Because this scale has only six notes, it does not have all the intervals of a major scale, or in any major mode. For instance, I labeled D# as a #5 instead of b6 since, everything has to relate to the chord you are going to play this scale over, and there's no chord with a b6 in its name. The lack of one interval inside this scale gives you that sort of unstable feel.
Another interesting feature of this scale is the number of augmented triads inside this scale. Starting from every note you can play an augmented triad or arpeggio.
2. Chords to Use With this Scale
Whole tone is used, mostly, in a "altered chords" situation. By altered chords I mean a dominant chord (a chord with a major 3rd and a minor 7th) with added altered tones (b9, #9, b5 or #11, #5 or b13).
If you want to use this scale sticking with the theory rules you should probably play whole tone just over an augmented chord with alterations that respect the scale. For instance, you wouldn't play A whole tone over A+(#9) since that chord has a #9 and whole tone as a regular 9.
In a real life context that scale is superimposed even over a regular dominant chord, just to create a really outside sound that immediately pops out.
3. Use the Correct Fingering
Here's the first fingering for G whole tone. I highlighted the root as G but you can start that same shape from whatever note in the scale and you will still play whole tone. In fact, there are only two whole tone scales, C and C#, because every note in the C scale is a whole tone scale too.
Here's a more "shred" style fingering that ascends a G whole tone scale.
I mentioned before that this scale has only augmented triads inside it. I pointed out a C# augmented since it's a familiar shape for me, but you can start from the interval you want, really.
Moving that shape up a whole step you will still be playing notes that are in the scale. This could be a nice device to use whenever you want to move along the neck, instead of playing always in the same area.
The use of this scale is definitely uncommon, and really odd sounding. From this point of view, the concept is heavy and not easy to digest.
I invite everyone that might be interested in "odd-sounding music", no matter the genre, to try to get this scale under your finger. It will add a big bonus to your improvisational skills!