Let's take a I chord in the key of C which is a C major chord made up of the notes C E and G. Now, if we extend the chord tones up to a 7th we add the B which is the major seventh. Taking this further up the extensions of this chord we will get to the 9, 11 and 13 which are D, F and A respectively. So now we have our fully extended chord tones of C E G B D F A. Let's rearrange those notes into ascending order and we will get C D E F G A B look familiar? It's our trusty old C major scale! So the C major scale is basically a flattened down Cmajor13 chord with all the trimmings. Now let's do they same with the ii chord, which in the key of C major is a Dm. Let's go up the extensions again for the ii chord, we have R b3 5 b7 9 11 and natural 13 which gives us the notes of D F A C E G B. Brilliant, a great sounding Dm13 arpeggio! Or is it? Let's rearrange the notes in ascending order again to D E F G A B C and we have a nice little D Dorian scale. This is the second mode of the C major scale, much like the ii chord is the second chord in the key of C major. This is no coincidence, the D Dorian mode is a squashed down Dm13 chord.
This works with all the chords you know and all the chords you do not yet know. Scales are the exact same notes as chords when they are fully extended. This is because we create chords scales by stacking up thirds of some kind on top of each other. This is "Tertian harmony" or harmony based on stacking thirds. Quartal harmony is common in jazz and is created by stacking fourths to create chords. So terms of scales vs chords, 2 = 9, 4 = 11 and 6 = 13.
So back to tertian harmony; much in the same way that we flattened a fully extended chord down to get to the scale we can arrange and stack a scale to create it's chords. Lets use the same examples in reverse, C major scale, and we use the 1st degree of the scale C. So our notes are C D E F G A B C and we basically play one miss one, play one, miss one, up the scale. So we get C, (miss D) E, (miss F), G, (miss A etc) B, D, F, A. Providing you start from the root of the chord you are choosing to build upon, then taking this approach will always give you some variant of the following chord tones in the following order, root, third, fifth, seventh, ninth, eleventh, thirteenth. I say 'some variant' because you may get to the flat third, or the flat seventh, or a sharp eleventh or something similar but regardless of 'flat/sharp/diminished/augmented' intervals, they will always be some kind of third, seventh, ninth etc.
Let's prove our point by doing the same from a different mode, the F Lydian scale. F Lydian has the notes of F G A B C D E, these are the intervals of root, major second, major third, sharp fourth, perfect fifth, major sixth and major seventh. If we stack these up in thirds as we do in tertial harmony we arrive at the notes F A C E G B D. A perfect Fmaj7#11 chord with the added extension of our 9 and 13 in there. This is the IV chord in a major key and that Maj7#11 is the defining sound of Lydian.
Even if we do something a little more "out there" like the whole tone scale which is a hexatonic (6 tone) scale, we arrive at the same concept. If we start from C and lay out the notes of the C whole tone scale we get C D E F# G# A# C. Now lets use the enharmonic equivalent for the A# which is Bb. If we stack these notes up like chord tones as before (play one miss one) we get the notes of C E G# Bb D F# which is a C7#5#11 chord with the chord tones of root, major third, augmented fifth, flat seventh, ninth, augmented fourth (this chord has no 13th because is it only a 6 note scale rather than a 7 note scale). Again it's certainly no coincidence that the whole tone scale is often played over a Dom7#5 chord!
I think that this way of viewing scales and harmony is a more "informed" approach. It's quite freeing because you no longer have to think "what scales will fit over this chord" or "what chords do I need to express the sound of this scale." Also another advantage is that the more simplified/vague the chord is, the more scale options you have because the extensions could be varied. For example a simple dominant seventh chord could imply Mixolydian, Altered, whole tone, lydian b7. All because the R, b3, 5, b7 is found in all of those chords. The scale choice gets more specific when the chords and extensions get more defined. If the Dom 7 chord also had a #11 in it then it's that lydian b7 that you want to use. The most vague of chords would be a power chord or 5th chord because it doesn't even imply major or minor, let alone types of sevenths or upper extensions. Root note grooves and power chord grooves can be the most fun at times. You will have to take context into consideration, firstly the context of the chord within the surrounding chords because this will help define your scale choice, and also the context of the genre. If you are trying to sound like happy upbeat country music, your altered scales may not be the best choice, despite the fact that the chord you are playing over (a G major for example) has all the right chord tones (R, 3, 5) to suggest it fitting in with an altered arpeggio (R, 3, 5, b7, b9, #9, #11, b13). So be careful.
So there you have it! All scales are chords anyway (arpeggios at the very least). Try viewing the notes on your instrument not by scales but as flattened out arpeggios and see how that works out for you. Jazz musicians do this all the time, they play modally, one scale per chord as the chords change and following the chord and key changes as they go.
Using this concept, it will also help you pull out extra chords and extensions on the fly because the entire scale you are visualising is just one big arpeggio.
Let me know how you get on with this concept.
About the Author:
By Steven Martin, www.stevenmartinguitar.com. If you enjoyed this article, share it on Facebook and Twitter, and be sure to get in touch with any questions or comments.