Hi Aor82 — I recognized the walking examples cuz' they're from my book,
Invalid Link Removed I did that book about 25 years ago, and actually the lines that you posted were originally from Jamey Aebersold's handout on how to create walking lines (When I originally talked with Jamey about putting this book out, he suggested I include the handout that we used at the Summer Jazz Workshops). The entire book is transcriptions of lines that I play on standards (with a playalong), and I give analysis of each line—why I play certain notes and rhythmic embellishments.
Fun fact: The notation copy work in the book was done by composer/bandleader Maria Schneider
Regarding the two choruses of blues you posted: Out of context, some of those notes might look weird, or not like the "best" choices theoretically (I'm looking at you, @Don Kasper
Those examples were also passed out as part of my handout package at countless workshops around the world, so you might just have the bass lines on a handout, without the benefit of the explanation in my
Bass Notes book (hint, hint).
The preceding choruses on the handout of "how to create bass lines" show all of the typical, chord tone, scale tone, and leading tone approaches. The two choruses you posted show a bass line that meanders chromatically through the changes, and hits various target notes — the root, 3rd, or 5th, one beats 1 and/or 3. Chorus 8 demonstrates a point I was trying to make about possible uses of chromaticism in a bass line. Lots of typical patterns in there, along with a few chromatic sidesteps.
Looking at chorus #9, bar 1 shows a typical Ron Carter thing — he tends to play R, b2, 2, 3 — rather than the often-played (and much-loved) R, 2, #2, 3 into a target note up a 4th.
Chorus #9, bar 3 is what some call a "double upper chromatic" approach . . . you play a note one half-step under the target, then come down from 2 half-steps above the target. Very common and useful.
Chorus #9, bar 6 has an "enclosure" on beats 3 & 4. Those two notes surround the target note F in the next bar. The Db in bar 7 is a chromatic approach note to the note C, the 5th of F7. In bar 8, there is an odd thing — the chord symbol says D7, but the bass line outlines A, C#, D, F#. This is just adding the secondary dominant (A7) before the D7, which bass players often do . . . I'm guessing that @Don Kasper will not like this part either . . .
A lot of chromatic pivoting happens in bars 9 & 10 of chorus #9. That's just a root, or target note (G on the Gmin7), then up a half-step and back down. Then the root of C7; up a half-step and back down. The F7 in the next bar is preceded by a chromatic approach note — Gb.
3. I attached a document with 2 instructional walking bass choruses with chromatic approach over blues standard. what is the theory behind them? what are the scales/modes and rules behind them?
The theory behind all of this is that the lines put a chord tone on beat 1 and maybe also on beat 3. The notes
in between the chord tones in these choruses are often outside of the chord, and function by leading into the next target note chromatically.
It sounds like you're trying to understand everything theoretically, which is great.
Bass lines can only have chord tones, scale tones and chromatic passing tones. Stable, clear bass lines often have roots on beat 1, probably another chord tone on beat 3, and a leading tone on beat 4. More melodic bass lines might use chord tones other than the root on beat 1. Melodic bass lines (Israel Crosby with Ahmad Jamal) might meander more chromatically than "root-always-on-beat-one" bass lines.
You'll be well served if you listen to real recordings of bass players playing walking lines on the blues. Make a playlist: Ron Carter, Ray Brown, Paul Chambers, Sam Jones, Doug Watkins, Oscar Pettiford . . . those players will align your ears to what sounds good. The answers are in the recordings, and then the theory comes later.
