For real though, there are lots of choices you get to make when soloing or coming up with melodies or harmonies. That’s where creativity comes into play.
The best advice I can give is to always create movement in your music; whether it be big key changes, slow and smooth shifts to another diatonic chord, make a rhythmic shift from 3 counts to 4 counts. Are perfect example of that rhythmic shift are most(all?) of Syn’s sweep picking etudes. So to be specific, sweep picking lesson IV goes from 8th notes(2’s), to 8th note triplets(3’s), to 16th notes(4’s, but dividable by 2’s), and finally 16th note triplets(6’s, but dividable by 3’s) and they are counted:
8th’s= 1 & 2 & 3 & 4 &
8th trip.= 1-trip-let 2-trip-let 3-trip-let 4-trip-let
16th’s= 1e&a 2e&a 3e&a 4e&a
16th trips= 1-trip-let &-trip-let 2-trip-let &-trip-let 3-trip-let &-trip-let 4-trip-let &-trip-let
There are lots of ways to create movement, but the one I kind of leading to now is you choice in melodic soloing devices. One of my music teachers a few years back, the wonderful Dan Gilbert, had a mantra he would always say in class: “Chord tone, key center, chord scale” and we would say it over and over. The idea is that these 3 ways of thinking about note choices are the foundation to improvising and sounding like you actually know what you’re doing. Of course there are endless ways to improvise and it’s not as easy as just being able to play these things, you have to play interesting rhythms and mix the notes up so you dont always sound like youre just playing scales up and down. But anyway, this is the explanation:
Chords tone- No matter what the chords progression is, you can ALWAYS play the notes of the chord that you are on and it will sound like you know what you’re doing. So if my chord progression is Dm | F | C | A7 | My chord tones are, and these are all 7th chords because the 7th is a chord tone too: D F A C, F A C E, C E G Bb, A C# E G. And the STRONGEST chord tone to play when you are trying to target each of those chords as they fly by is the 3rd or the 7th of each chord because those notes define whether or not the chord is Major, Minor, or Dominant- Just like those modes we were talking about.
Key Center- This is what most people do when they first start learning to solo. You figure out what key a series of chord are in, whether its a major key or minor key, and you just play that major or minor scale. So if my chord progression is Dm | F | C | Am | I just think in the D minor scale for my whole music idea because those chords are all built from the D minor scale. D E F G A Bb C D. Notice all the notes in the arepeggios from the chord tones section are in that scale, except for the C# because the dominant 7th on the V chord is probably the most common chord substitution and the strongest musical movement in music- V7 – i or V7 – I. So again, just playing scale ideas.
Chord Scale- This is to bring everything full circle with you question about Dorian. One common thing some jazz guys do to create movement is to follow the chords by playing chord scales over the chords as they pass, which in my opinion is the most difficult to do to follow chord changes. They play a different scale that is specific to each chord. The most common way to do this is playing the Dorian scale over every minor chord, the Lydian scale over every major chord, and the altered scale over every dominant 7th chord. So if my chord progression is
Dm | F | C | Am | the scale for each chord are:
D Dorian- D E F G A B C D
F Lydian- F G A B C D E F (same as D Dorian)
C Lydian- C D E F# G A B C
A Dorian- A B C D E F# G A (same as C Lydian)
In that case you would only really be playing in 2 different key centers because the first 2 chord scales(or modes) come from the same major key and the second 2 come from the same major key.
You could change that last chord to an A7 and now the chords are Dm | F | C | A7 |
D Dorian- D E F G A B C D
F Lydian- F G A B C D E F (same as D Dorian)
C Lydian- C D E F# G A B C
A Altered- A Bb C C# Eb F G (the altered scale comes from the melodic minor scale and is some hip jazz shit)
Or you could change the progression to some almost completely unrelated chords that dont share any scales like Dm | Fm | Am | Cm and then play dorian over each chord:
D Dorian- D E F G A B C D
F Dorian- F G Ab Bb C D Eb F
A Dorian- A B C D E F# G A
C Dorian- C D Eb F G A Bb C
Or if they were all major, you could use lydian over each.
2 general rules of thumb now that you have heard some note choice strategies:
1) it generally sounds better when you play chord tones on the strong beats of the song and color tones or passing tones on the weak beats. So if youre counting straight 8th notes(1+2+3+4+) the down beats(1234) are strong and the up beats(++++) are weak. Or if youre playing in 12/8 and you count in triplets- 1-23 2-23 3-23 4-23, the strong beats are the 1 2 3 4 at the beginning of each set of numbers. The strong beat is the pulse of the song.
2) You will likely flow better when soloing over chord changes if you’re always thinking about where you are going rather than where you are. So if my chord progression is Dm | F | C | A7 | When I am on Dm, I’m thinking about playing an FM arpeggio or lick next, then while I’m playing that FM lick, Im think about those notes landing on some C chord tones, and so forth…..
I know this is a ton to take in, but the whole point is that you have a TON of options and that means YOU have to make a choice on what notes you want to play and what YOU have to say as a musician. There are some guidelines to music but there are no rules. Its your world, experiment with it.