Updated: Jan 17
This is the full Percy Heath bass transcription from Miles Davis' 1957 "Bag's Groove" album title track.
[Update: this is Take 1. Thank you Sean for asking about this!]
The first thing that stands out to my ears: the staccato notes. From a purely educational standpoint, I recommend that students actually do not mimic this. Music has come a long way in the last 60 years, and habitual staccato notes during a walking line tend to sound like a march.
It's not WRONG, per se, but in my experience (take it or leave it) is that short notes would probably catch the ears of the other band members. They stick out, for better or worse. So I recommend thinking of staccato walking notes as a tool to employ on occasion, rather than something to habitualize.
When I ask myself, "What can I take away from this bass line for my own playing?" I like to look at two things:
1) What moments are repeated over and over?
2) What moments are special events?
For example, in this bass line, what does Heath do again and again that might be of value?
The fundamentals come to mind right away. Solid time, chord & approach tones, tension & release, and playing the root note on beat 1 of each measure.
It's better, at least in this particular musical setting, to create a reliable, solid background against which special events will be felt. Heath does a marvelous job of this. For example, the quarter note triplet at measure 408, playing an A on the downbeat of a C7 at measure 142, etc... these are all special events that sound like special events because the rest of the line is solid, even predictable (in a good way).
I heard a teacher say recently, "Blue doesn't stand out against blue." How true! Applied to walking bass lines: if everything is unusual (durations, rhythms, note choices, etc.), nothing is unusual.