Thanks bandcoach, you mentioning the cycle of fifths makes it a little easier to understand, seeing that each diatonic triad in a particular scale are chords played in the cycle of fifths related to that specific key. By determining the diatonic triads of any given key, we then know the cycle of fifths.
Would it be safe to say then, based on your example, that if I'm in the key of Dm, for example, I'm using a Dorian Minor Scale?
Not necessarily - the Key of D minor should be based on the Major scale of F - i.e. it has a B[sup]b[/sup] in it. if it were the Harmonic minor, then it would have both B[sup]b[/sup] and C[sup]#[/sup]. If we were to use the Key of C major from which to derive your Dm key, then yes it would be D Dorian.
Also if I didn't have a cycle of fifths chart handy which I currently use, determining my diatonic triads for any key, I could determine the chords assigned to each roman numeral in order for me to produce chord progressions?
Yes.
Also maye you can explain this,
in my cycle of fifths chart say for example im I'm the key of C, my iii = Em chord, but above the Em there's a small m7, does that mean that I could play either Em or Em7?
Yes; any chord can be extended to the 7th or the 9th or beyond - in each case it is a matter of reading through the currently active scale starting on the chord naming note and skipping every other note until you have reached the required extension.
In C major for an Em[sup]9[/sup] this would be:
C-D-E-F-G-A-B-C-D-E-F-G-A-B-C-D-E-F-G-A-B-C
In G Major for Em[sup]9[/sup] this would be
G-A-B-C-D-E-F[sup]#[/sup]-G-A-B-C-D-E-F[sup]#[/sup]-G-A-B-C-D-E-F-G
In D Major for Em[sup]9[/sup] this would be
D-E-F[sup]#[/sup]-G-A-B-C[sup]#[/sup]-D-E-F[sup]#[/sup]-G-A-B-C[sup]#[/sup]-D-E-F[sup]#[/sup]-G-A-B-C[sup]#[/sup]-D
I use three octaves of the relevant scale so that I can extend up to the 13th for any starting note (A 13th is 2 notes short of two octaves, so If I start on the leading tone of the scale, I need another two octaves (almost) to get to the last note in the leading tone diminished 13th (7-2-4-6-1-3-5)
I could of course just use chord spelling based on scale tones, but this could lead to the wrong notes being written - safer to use the notes of the scale laid out and take those that are needed for the particular chord.....
