OK so it was more than a week since my last blog...I've been getting a job and moving to a new apartment. Forgive me.
 
But here it is...so buckle down and enjoy!
 
THE GROUND LOOP
Vol. 2  - The Modal System (basics)
WARNING - This article assumes basic knowledge of fundamental concepts in music theory. That is, you should know a major scale, and what it sounds like / how to create one in any key. For simplicity it's all in C here.
So you've heard some guy say "I think a Phrygian scale would sound cool over that". And you thought, "WTF is a Phrygian?" Well, Here is the short history:
A long time ago, when music was first starting to be written down, the Catholic church decided that music needed to be organized. They did not have "chords" like we do...they did not even use our tuning system! (Bach wasn't born for another 300 years yet). 
Here's how they organized it:
What we would call the C major scale would have been their Ionian mode. They have "chant notes" in each mode that are based in the Pythagorean system of perfect 4ths, 5ths, and octaves. For instance, the popular chant notes in the Ionian mode were the 4th and 5th scale degrees.
Well, that being said, they did not particularly like the sound of the Ionian mode ;) Most music extant from that period is in Aeolian, Dorian, and Phrygian modes. 
Sow how are we to get the different modes?
Take your C major scale, no sharps, no flats:

C D E F G A B C 
That's the "Ionian" mode. Simple so far, right?
Now extend it 2 octaves (for demonstration purposes)
C D E F G A B C D E F G A B C 
Start on D and finish on D. Sounds funky huh? That's the Dorian mode.
E to E is even weirder. That's the Phrygian mode.
And so on in that pattern. Here's the names based on the scale degrees:
I - Ionian
ii - Dorian
iii - Phrygian
IV - Lydian
V - Mixolydian
VI - Aeolian
VII - Locrian
To be perfectly correct however, you would not call these "C Dorian" or "C Lydian". You name them from the note on which they are based. So, D Dorian, E Phrygian, F Lydian, G Mixolydian, A Aeolian, and B Locrian are all in the "key" of C. What makes the difference is...blast from the past here...the "chant" notes, or the notes on which you begin, end, and dwell on in the middle. 
For instance, if I play a C major, but I solo over it beginning on an A, hitting a D and an E a lot, and then returning eventually to an A, I have just played A Aeolian (Or, as we call it these days, A Natural Minor) over a C Major chord. It's in the key, but it sounds a little odd.
"But," you may ask, "how do they relate to each other? what if they all started on C?"
Great question!
Here's how they work in terms of intervals (each - represents the notes of the scale, W = whole step, H = half step)
Ionian     -W-W-H-W-W-W-H- 
Dorian     -W-H-W-W-W-H-W-
Phrygian  -H-W-W-W-H-W-W-
Lydian     -W-W-W-H-W-W-H-
Mixolydian     -W-W-H-W-W-H-W-
Aeolian     -W-H-W-W-H-W-W-
Locrian    -H-W-W-H-W-W-W
So, each scale beginning on C, here's how those look:
Ionian     C D E F G A B C
Dorian     C D Eb F G A Bb C
Phrygian  C Db Eb F G Ab Bb C
Lydian     C D E F# G A B C
Mixolydian C D E F G A Bb C
Aeolian     C D Eb F G Ab Bb C
Locrian    C Db Eb F Gb Ab Bb C
I know formatting doesn't work that well, so if you'd like a copy in .doc format, shoot me a message and I'll send it to you.
Keep rockin!