Here is a write up on modal theory.Hope it is useful to you

[Paul Secondino]

SOme guys on another forum with the exception of one were doing a bad job of explaining modal theory and practical application.So I wrote a small book on it.I hope some of you find it useful and easy to understand/apply.Jsut scroll down the page a little that this link takes you to on the Dream Theater Forum

Click Here For it

[Devo]

the only thing I would say is that strictly speaking if your writing a modal piece of music not all the chords and certainly not all the seventh chords are available to you. Modes are kind of fragile because of the tendency for the music to shift towards the nearest major whenever you introduce the flat5 (diminished) chord.

Thats why you never really see big elaborate chord progressions in modal music, and there is a tendancey to repeat just two or three chords and often over a tonic drone, any satriani or indigenous folk music including most nationalistic music from glinka to bartok demonstrates this.

steve

[Paul Secondino]

Most beginner to intermediate musicians ask "how do I know what chords I can use when I use this chord or when I use that one.?" The fragmented modal write ups tend to confuse them.

Even though there are many accurate articles all over the net, my students are able to get the sense of modal theory when they realize that any major key signature can be looked at as having 7 personalities.

As you say though, writing a song with a strong modal hook doesn't require the use of all 7 basic available chords.But then again, what song ever needed all 7 diatonic chords? Composing music is the true art form.All of the theory is only useful for providing a framework to work within or around.

[Devo]

I just remember when I was trying to learn about modes and being given
big lists of chords and scales like if you have a dominant 7th you can play
mixolydian, lydian flat7, overtone, augmented dominant, whole tone. It
wasnt till years later when I sat down to write a contemporary choral
piece for a local choir and worked out the chord relationships and all the
harmony for a number of modes and synthetic scales that its all sort of
clicked.

for example if you have a II chord in G major (ie A minor) by itself it
implies no more A dorian than A phrygian or A aeolian. I think modality is
better off explained in terms of harmony, cadences and resolutions. too
many people use modes, particularly the modes of G major as a way of
learning to play in E all over the neck of the guitar. You can start your
scale passage on B but the truth is your still in E minor folks.

"Only when theory and technique are combined with imagination and
talent do works of importance result" None of these aspects should be
neglected and none should be given more importance than any of the
others in my opinion. Unless your content to always play other peoples
work I think you should make an effort to develop each of these aspects
of your musicality. Your compostition will only benefit from it.

Steve