When you play walking bass in a band, do you have lines memorized or the chord progressions memorized?
I play bass in my schools jazz band but all of our music is written down so I have no experience with coming up with my own lines and I don't know how to approach it.
"Memorized" is not really the best way to look at it. Eventually your note choices should be made by what you HEAR.
First of all, playing with a big band/large ensemble (particularly in advanced high school or general university ) is more about playing arrangements of compositions rather than a small group approach of having a 'conversation' within the framework of a specific melody and harmonic form (chord progression) . But even big band charts will often have sections where you are simply given the chord changes and are expected to create a line based on that progression. So there are some basic skill sets you need to have in your ears and under your fingers:
SCALES - major, natural minor, harmonic minor, and (jazz) melodic minor in at least two octaves
TRIADS - major, minor, diminished, and augmented in all inversions and in open and closed position
4 PART CHORDS - maj7, dom7, minor7, tonic minor7 (minMaj7), half diminished, augmented 7, augMaj7, open and closed positions
That way when you see a chord progression (Dmin7 G7 to Cmaj7 for example)
1. you know what notes are in each chord (D F A C. G B D F. C E G B)
2. you can see how inversions can help you keep proximities in fingering by playing the common tones on the same fret/in the same position and playing the non common tones a half or whole step away
D minor7 in 2nd inversion (A C
D F)
G7 in root position (G B
D F)
Cmaj7 in 2nd inversion (
G B C E)
3. you can start to hear how using intermediary notes from the scales can link the chord changes and build an arc through the progression, rather than just arpeggiating each chord as it happens.
Because THAT'S the "approach" - walking bass should do 3 things:
1. provide
harmonic definition - bass provides the
foundation or the harmony/chords. The most basic way to define the chord is to arpeggiate it.
2. provide
harmonic propulsion - that is playing in such a way that there is the feeling of forward motion from one chord to the next (that's why they call it a chord
progression, right?) So note choices have to
move the music forward.
3. provide
melodicism - your line should be as much a melodic response to the chord changes within the parameter of being all quarter notes and fulfilling the two prior functions as your ear and wit allow.