Hey folks,
there seems to be lots and lots of questions about modes/keys lately so I
have decided to wite a kind of tutorial on it.
The first thing you going to have to do if you want to play in F dorian is to
write a
chord progression that is in F dorian!

seems pretty obvious
But how do you do that??
When writing in any mode you have three basic sets of chords.
1) The primary chords which include the tonic chord and the chords that
include the distinctive flavour of that mode.
2) The secondary set of chords are all of the other chords excluding the
tertiary chord/chords
3) The diminished chords are the set of chords that contain the diminished
fifth or tritone (usually only one in each mode/key). In general this chord
is rarely used as it suggests the dominant seventh of the major key with
the same number of sharps or flats as the mode in question and destroys
its modal feel.
So basically your chord progression is going to start on the tonic chord
and then go through a bunch of primary and secondary chords and end
up on the tonic again, while all the time trying to avoid that diminished
chord. The unique sound of your music is going to come from the order in
which you place the chords in your progression. And this will ultimatly
allow you to create new and interesting melodies.
Examples.
In the lydian mode (which seems to have much popularity on this forum)
the characteristic flavour is the raised fourth step (When compared to the
major scale).
The chords that contain this flavour are the chords of II and VII.
Therefore the primary chords are I (because the tonic is always a
primary chord), II and VII.
the dimished chord is IV because a diminished fifth is created between
the raised fourth and the tonic.
The secondary chords are therefore all the ones i have not mentioned i.e.
III, V and VI.
For example in E lydian A# is the flavour note.
Primary chords
I = E,G#,B
II = F#,A#,C#
VII = D#, F#, A#
Diminished chord is IV = A#, C# E
(the interval between A# and E is a tritone and resembles F#, A#, C# E,
which is the dominant seventh of B major hence when this chord is
sounded there is a tendency for the music to feel more B major-ish then
E lydian and move in that direction destroying the lydian feel) Nearly all
examples of modal writing I have looked at avoid using the dimishesd
chord or uses a modified chord, which i wont deal with here.
Secondary chords are
III = G#, B, D#
V = B, D#, F#
VI = C#, E, G#
In the DORIAN mode the characteristic flavour is the raised sixth step
(when compared to the natural minor scale)
therefore the primary chords are the tonic chord (i.e. I) plus those chords
that contain this raised sixth step (i.e. II and IV) the dimished chord falls
on the characteristic step of that scale (i.e. VI) and therefore the
secondary chords are III, V, VII.
In the PHRYGIAN mode the characteristic flavour is the flattened second
step (when compared to the natural minor scale)
therefore the primary chords are the tonic chord (i.e. I) plus those chords
that contain this flattend second step (i.e. II and VII) the dimished chord
falls on the fifth step of that scale (i.e. V) and therefore the secondary
chords are III, IV, VI.
In the MIXOLYDIAN mode the characteristic flavour is the flattened
seventh step (when compared to the major scale).
therefore the primary chords are the tonic chord (i.e. I) plus those chords
that contain this flattened seventh step (i.e. V and VII) the dimished
chord is III and therefore the secondary chords are II, IV, VI.
The LOCRIAN mode is the odd one out and is in general infrequently used
as the tonic chord is also the dimished chord which makes it unstable.
The use of seventh/nineth chords in modal writing:
as a general rule the only really use-able seventh and nineth chords are
those that dont contain the dimished fifth.
So as an example of 7th chords in E lydian you have the tritone between
A# and E so therefore as the chord of four is already excluded the only
other chord that need be excluded is II7 (F#,A#,C#,E). All other seventh
chords are ok.
The nineth chords of IV, II, III and VII also contain the Diminished fifth
and must be excluded for this reason.
OK now we have covered what chords we can and cant use to maintain
the modal feel.
Simple lydian example here:
Yoink!!!!
In this example I started on the tonic chord, then played a primary chord
(contains the A#) of VII added a seventh to give it a more airy sound. the
played a secondary chord (III) then another secondary (VI7) then a
pseudo primary V7 (as it contains the A#) and then back to the tonic
Chords progression in above example = I, VII7b, III, VI7, V7, I
Forgot to use nineths, sorry.
Next time I will cover synthetic scales modes and their uses.