One of the tricks of Bebop is to extend the scale by one note so that there are 8 distinct tones ot be played in a measure, which, in 4/4 time, is divided into 8 eighth notes. For a major scale, you add the #5. When you do this, the down beat hits one of the main notes of the chord.
If I use capitals for chord tones and lower case for transitory notes, it can be written for C Maj like this:
C d E f G g# A b C
This really is more of a C6 than a CMaj7 scale, but they are pretty interchangeable, and the A is just as strong a tone as the b, if not stronger.
For a Harmonic minor, you don’t want to damage the sound of the minor third that you get between the 6th and 7th notes of the scale. Thus, you have to find another note to add. One good possibility is the tri-tone (Aug 4 or Flat 5).Â The resulting scale for an A Harmonic minor is
A b C d Eb e F g# A
This tone is a good candidate, as it turns the first half of the Harmonic minor scale into a diminished scale. The diminished and th harmonic minor share a very similar tone, even amongst the varying minor scales. The diminished scale is very regular whith hole tone following half tone so regularly that it is hard to distinguished one segment of the scalre from another. The minor third in the Final block of the Harmonic mnor reinforces the minor third you hear lower in the scale, but cranks it up a notch. What you her implicit with the passing tones become implicit.
The substitution isn’t perfect.Â Ideally, the added not should be one that keeps the chord tones as the down beats.Â Unfortunately, doing that in the Harmonic Minor has the drawback that the only place that works is in the middle of the minor third that gives the scale its distinctive sound.Â This is a compromise. It really represents a transition point in how you play the scale. If you play the whole scale from low to high, it works perfectly. Hower, turnarounds in the vicinity of the tri-tone will often sound out of the Klezmer vocabulary if it foreign not is played too many times in near succession. Harmonic minor with an added tritone makes a pretty good Klezmer Bebop scale.