Part I - Arpeggios
The arpeggios we need to walk over a ii-V-I chord progression in the key of C major.
I chord: C maj 7: C - E - G - B
ii chord: D min 7: D - F - A -C
V chord: G 7: G - B - D - F
Part II: Creating a Walking Bass Line
This video covers the "textbook" method for creating a walking bass line. If you're playing in 4/4, then you have 4 quarter notes that you've got to come up with for each bar. Those four notes should be the following:
1. A chord tone (usually the root of the chord)
2 A scale tone
3. Another chord tone
4. A Passing tone: A note that's a half step above or a half step below the root of the chord in the next bar.
That’s a very cut and dry explanation, but those are the basics. For example, if you’re playing 4 beats to a measure, and the chord you’re walking over is C, the notes in the chord C are: C - E - G. We’ll also assume that the chord C, in this case, is in the key of C, meaning you’ll use the notes from the C major scale for the scale tones (C-D-E-F-G-A-B-C.) So, a walking bass line over this chord might be: C (chord tone and root of the chord,) D (scale tone,) E (chord tone,) and then the last note will be a passing tone (a note a half step above or a half step below the root of the next chord in the song. (So if the next chord is G7, you’ll play F# or Ab.)
To re-iterate, if we’re reading a chord chart that asks us to walk over a Dmin7 chord for four beats, and then moves to an G7 chord for four beats and then to Cmaj7 for eight beats, we might play: D E F Ab | G A B Db | C D E F |G F E Eb :|| This is the simple explanation, and we are not tied rigidly to these rules. Ultimately, a good walking bass line should create an interesting counter melody that provides a strong harmonic foundation for the other players to play against, and the technical “rules” can be quickly cast aside, as long as what we’re playing outlines the chords in a clear and musical way.