When asked about practising scales in improvisation and jazz, I tend to shy away from talking about it in any detail because, quite often, too strong an emphasis on scales and arpeggios gets in the way of making fluid music, and discourages us from just getting stuck in and having a go.
It can also lead to a "music by numbers" approach, where you have a particular set of licks for a specific chord change.
However, there does come a point when serious solid work on intervals, scales and arpeggios is the best way to develop. Possibly, the only way to merge theory with practice..
For me, the point about such practice is to build an internal map of tonality that correlates directly with our knowledge of the fingerboard. Simply put, you end up knowing where to find any note wherever you are on the fingerboard, solely by ear and "muscle memory".
So, here is the scale system that I have been developing over the past few years.
Remember always play scales slowly, without vibrato, and repeat until any intonation difficulties are ironed out, then do a further half dozen times, so that you have played the scale in tune more times than you played it out of tune.
There are four strands to this system, Modes, Intervals, Chords, and Scale Fragments.
This first section will look at the first strand, Modes.
Many people get confused about modes. The best thing is to remember that all you are doing is playing the same scale starting on different notes.
So the first exercise would be just that. In C:-
CDEFGABC'C'BAGFEDC C Ionian
DEFGABC'DDC'BAGFED D Dorian
EFGABC'DEEDC'BAGFE E Phrygian
etc.
This just gets us used to all the modes in one key. That is to say, we are sticking to the pitchset of C major, but building our scales from each degree in turn. It is vital to stay within one key so as to internalise all the interval relationships within that key.
Now the next bit is what gets us to develop hearing the tonal centre of each mode, and how the rest of the scale relates to it.
What you do is to put the first note of the mode you are on after every other note:-
CC DC EC FC GC AC BC C'C C'C' BC' AC' GC' FC' EC' DC 'C
DD ED FD GD AD BD C'D D'D D'D' C'D' BD' AD' GD' FD' ED' D
EE FE GF AE BE C'E D'E E'E E'E' D'E' C'E' BE' AE' GE' FE' E
etc.
C' means the octave above C.
This fixes in your mind's ear how all the modes relate to their roots, or tonal centres.
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So the second section of this system is to practise intervals.
If you have done the mode work I have described, then you have already played all of the pairs of notes in your scale in sequence. What you do now, is to group them according to the interval rather than where they come in the scale.
Again, we will use C major as our example
First, run up and down the scale over a couple of octaves. NOT fast, but just to tune up the ears and hands (We have to tune our hands more than the fiddle's strings). No Vibrato.
So, first we play up and down, one octave in broken thirds:-
CE DF EG FA GB AC' BD' C' E'C' D'B C'A BG AF GE FD C
Note by ear which are major thirds and which are minor.
Then in fourths:-
CF DG EA FB GC' AD' BE' C' F'C' E'B D'A C'G BF AE GD FC
Again note where the augmented fourth comes
You do this for fifths, sixths and sevenths, noting how the intervals vary from major to minor, or perfect to diminished.
You don't really need to do this for all the modes, as you are already fixing them using the other method.
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So, next come the chords.
The first scale of broken intervals we played was in thirds.
We then add the fifth to give us a triad off each degree of the scale.
Again in C Major,
CEG DFA EGB FAC GBD ACE BDF
Then we add the seventh:-
CEGB DFAC EGBD FACE GBDF ACEG BDFA
This gives us CMaj7, Dmin7, Emin7, FMaj7, G7, Amin7, & Bmin7b5 (half-dminished)
The pattern of M7, min7, min7, Maj7 Dominant 7, min7, and min7b5 is a template for the chords of all major scales.
Practise these coming down as well as going up.
Then do them going round the circle of fourths:
FMaj7 Bm7b5 Em7 Am7 Dm7 G7 CMaj7
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Now we can start to build our melodic units.
We will use four note fragments to begin with, as we have four fingers. You can always add more later.
There are only 6 orders we can put our four fingers into:-
1234
1243
1324
1342
1423
1432
Repeating each of these, or starting on a different finger each time gives us all 24 permutations of four notes.
So we start on the first degree of the scale, and go through each of these finger patterns.
Or you can stick to one finger pattern, and go from one scale degree to the next.
Or change the pattern as you go up the scale.
Once you get the idea, you can make up your own exercises, and change any aspect of the pattern. E. G, don't use consecutive notes., so instead of going CDEF, go CEFG. Or CDFG. and go through the permutations of that.
Soon you realise you can find any note from any note, and the basic work is done for the major scales.
Then you have to do the same thing for the OTHER scales!
OK, here are the main scales to get under your belt.
Major
Harmonic Minor
Melodic Minor Ascending (practise in both directions; descending melodic minor is the same as the Aeolian mode)
Harmonic Major (1 2 3 4 5 b6 7)
Diminished ( interval pattern: ST T ST T ST T or T ST T ST T ST)
Whole Tone
Augmented (interval pattern ST +2 ST +2 ST or +2 ST +2 ST +2)
Chromatic
Minor pentatonics
Major pentatonics
You can insert extra semitones wherever you like to create more scales, such as blues or bebop scales.