Quote from: EdGrissom on Nov 20, 2017, 03:55AMI do things the "wrong way" according to many of you, but I only think in terms of the major scale. Then I just start them on other scale tones than the tonic to play all the different modes. For example, if I have to play in D minor Dorian, I just play the C major scale starting on D. If I have to play over an Bb dominant, I'll use the Eb major scale starting on Bb.
If you only memorize the 12 majors and can start them on all 7 degrees, then all you have to do is figure out which one to use in each situation.
I think that's how a lot of people do it. After doing that for a certain amount of time though, you do stat to think of ones you frequently use more handily than ones you don't. D dorian for me is every bit as natural as C major for me. D# minor less so!
The important part to me is that you not just do the scales, but the arpeggios and chord outlines. As in, you can play 7,5,3,1 or b9, 5, 7, 3, etc. and the various permutations. I did a little studying with a saxophone player this year and it occurred to me that saxophonists tend to do a lot more intervals in their improvising rather than scalar stuff. Makes sense, the instrument is setup to be able to do that a little more easily than trombone in some ways. (Best demonstration that comes to mind is
Coltrane's solo on Giant steps.
In other words, in my experience, the best way isn't to think of scales as scales per se but to think about the important parts of a chord and fill in the gaps. Think of a ii-V7-I in Bb for example. If you just get the 4 chord tones for each of the three chords, you only really need to remember 12 notes total. But you can play some pretty convincing licks over them:
Cm -> F7 -> Bb
[Eb, G, C, Bb] -> [A, C, F, Eb] -> [D]
Then as you get good at getting these "important" notes, fill in with the notes in between. That's where the scales come in. In this example, the Cm is really C dorian, so A is natural. So you can arrive at the A while still in the Cm chord and do an anticipation to the third of the F7 chord. Etc.
Cm -> F7 -> Bb
[Eb, F, G, A] -> [A, Bb, C, D] -> [D]
This approach is a lot easier for me since you only have to really know the 3,5, 7 of any chord to compute the rest of the notes. The 9th is easy since its just the next whole step. (Or +1/2 if its a b9 chord.) Once you can compute these 5 notes easily, work on 11ths (4ths). Then do your 6ths(/13s). Voila! You have the whole scale now! No memorization required either, but eventually you will memorize them.
Diminished scales are a little bit different:
I think of fully-diminished chords as being #1,3,5,b7. So B dim is a Bb7 chord starting on B. (B, D, F, Ab) That's a little backwards, but I learned it from Matt Niess. So if its good enough for him, its good enough for me

The scale you play over this are the halfsteps below the arpeggio. So A#, B, C#, D, E, F, G, Ab. Note that the intervals in a diminished chord are fully symmetrical, meaning that any of the notes in the chord can be root. That means that there are really only two scales you have to learn. Bdim and Bb dim. Every other diminished chord is one of those two scales, but starting on a different note.
Half diminished is just the 7th scale degree of the relative major, so B half-dim is B, D, F, A. I don't have an expedient. BUt I will say that when I see a half-dim, I generally will arpeggiate until I can be a step away from the 3rd of the next chord. So if its like, B half-dim -> C I'll do [D, A, G, F] -> [E]
Or tl;dr, if you get the arpeggios down first, all you have to do is memorize what the 3rd, 5th, and 7th are. The root should be obvious from the scale you're playing. So memorize those three. Then you can compute the other 2 notes and eventually those will be memorized too if you use them enough.