Hey there...
I wrote an 'article' on this from my own explorations that took this idea still further and provides a framework to work out of for more chromatic work and 'quartal' harmony ideas...
projectguitar.ibforums.com/index.php?showtopic=16881&hl=pentatonicsThe Secret Life Of Pentatonics, Quartal Harmony & the Chromatic ScaleIt can be quite a powerful tool...my ideas come from the realization that the pentatonic scale can be seen to be a "stack of fourths"...
For instance, A minor pentatonic
A,C,D,E,G
These notes could just as easily be reordered to produce...
E,A,D,G,C
You can see the pattern is the interval of a fourth between each note (notice it is like the tuning of the guitar...except for that pesky B string tuning)
understanding this you can see how the pentatonics can be moved around to become more "out" and in fact become 'chromatic'...
You can see that you could
extend this pattern of fourths to extend the pentatonics...perhaps add another fourth above that C to give you the note F (nice if the iv chord in A minor say is Dm) or again to give you Bb, giving you a b9 sound making a beautiful cadance into a Dm chord from Am. On more and you get the note Eb, a nice b5 blue note sound that can resolve down to Dm nicely too. Another and you get G#, the leading tone in Am and so adding some harmonic minor touches and good for say when there is a dominant V7 or E7 chord in A minor...and so it goes...if you keep staking fourths you will eventually get every note of the chromatic scale!
It's useful and a powerful concept, but it doesn't replace other theory and fundamentals. Many on guitar learn by visual patterns and this is great, but to really progress you need to learn all the notes on the fretboard independent of these patterns, this is perhaps a fundamental.
The more theory oriented stuff is to learn how individual notes function melodically and this is something that is rarely fleshed out I feel. You also need to learn about 'progressions' and so where to apply these kinds of ideas.
A "lydian progression" for instance might be something like Dmaj7 to Amaj7 where D is the key (featured in the song "short note" by aussie band Matt Finnish that I play sometimes). You could approach this by mixing D major pentatonic and A major pentatonic...the "lydian" flavour comes from the #11 (or #4) note, G#. This has a pull "up" toward the A or fifth of Dmaj. It sounds quite different from the same note Ab treated as a b5 blue note in the same key, this is often a passing note between A and G and has a tendency to "fall" towards the third of a chord.
So, modes are kind of misunderstood by quite a few and misapplied...
You can get other 'schemes' such as Satrianis "pitch axis' thing or larry carlton's "super arpeggio" scheme, both players that use superimposition ideas a fair bit...but there are plenty more as well.
Pentatonics though do make a fine 'scaffold' to work out of and certainly the predominant way I treat scales and modes in playing (though I know them for what they are without the pentatonic thing)
It is very easy to add notes to the pentatonic for scales, add two notes to get a variety of common and unusual 7 note scales or even more.
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Another thing you may well be interested in is the creation of scales from the chord superimposition.
Take for instance a pair of chords such as F and E major.
F=F,A,C ~ E=E,G#,B
combine and you get a 'scale' E,F,G#,A,B,C
this kind of thing produces melodic notes 'exotic' in nature, perhaps a bit "spanish or arabic', shades of Dick dales Miserlou and certainly applicable over the chord change or on a static Am perhaps.
Another one might be A and G triads
A=A,C#,E ~ G=G,B,D
combine for...
A,B,C#,D,E,G
a six note version of A mixolydian (without the F#)
These things can be easy to "visualize" if you learn basic three note triads all over the neck.
A chord like G with an A bass is a staple in gospel and jazz sounds...think of tunes like Marvin Gaye's "what's going on", Jeff Becks version of "people get ready" or a lot of Steely Dan harmony.
Add Am and Em triads to get the pentatonic plus a ninth...etc
Playing with these ideas may inspire more interesting "lines" as they imply leaps and harmony and make "sense" to the ear while introducing some leaps that avoids a tendency to play sequentially through a scale or with the same "vocabulary" that scales like pentatonics suggest. So, Am and Dm makes a 5 note scale set, A,C,D,E,F...natural minor or aeolian mode without the note G, by avoiding this note you can get some interesting melodic lines such as a leap from F to A...
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Of course if you consider the pentatonic like a chord or stack of fourths, you can superimpose those just the same...
Am and Bm say...
A,C,D,E,G plus B,D,E,F#,A
make A,B,C,D,E,F#,G or A dorian...good for your santana like stuff over a Am to D major vamp say. So these kinds of principles can arrive at the same 'result' as modes, but it doesn't replace coming to grips with the 'concept' of how they work...
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Hope some of this makes sense and aids you in your explorations...pete
