EXPLORING JAZZ ARRANGING
Using Garritan Jazz & Big Band
ONLINE INTERACTIVE EDITION
by Chuck Israels



Lesson 2 - Bass Lines



The rhythm section as a “continuo” part.

The core of traditional jazz band orchestration is the rhythm section – most often a bass instrument, some percussion, and a chord instrument. Though there have been useful variations mothered by necessity, convenience, and a desire for variety, the traditional standard of string bass, jazz drum set, and piano, is a good place to start.
(It is always possible, for reasons of creative variety or availability, to make omissions or substitutions in orchestration, but the traditional jazz rhythm section provides a good internal balance and functions well with a variety of other instrumental combinations. The tradition has developed for good and practical reasons.)
Assuming that we are working with an established melody that has good balance, and that we have been given, or have chosen, a basic harmonic outline to go with it, lavishing attention to the details in the bass part can provide the most obvious benefit. The relationship between the outer voices carries information that trumps other details when it comes to solidifying musical structure. Bach recognized this, and little has changed in any essential way since his time. All the old principles of four-part harmony apply to jazz arranging (except for the fact that the basic harmonic unit in jazz is the 7th chord rather than the triad; this changes a few of the voice leading priorities but not the general principles. See Chapter 3, example 3-1.)

Contrary motion between bass and treble should be a prevailing texture with occasional passages of parallel motion when chord progressions are moving by step, and when the interval between the bass and melody is something other than an octave or a fifth.
(The traditional reason for the avoidance of parallel octaves and fifths in classical practice, that the overtones of the bass notes tend to swallow the upper part with a resulting loss of an independent voice, continues to hold true in jazz harmony, at least in how it applies to the prominent outer voices.)






Score References & Musical Examples Using JABB:


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Principles of Jazz Bass Line Construction

In jazz style bass lines, chord roots normally appear on the downbeat. The rest of the measure makes a melodic connection to the next chord root (emphasizing basic chord tones) while maintaining as much of the sound of the harmony as possible. That can prove to be a tall order when there are only one to three notes left with which to accomplish this. But it turns out that intervallic distances between successive roots in conventional harmonic progressions fall into predictable patterns, and that predictability elicits certain bass line shapes that, once recognized, can be plugged in to the music in phrases, rather than having to create the line, note by note.

HERE ARE SOME TYPICAL ONE-MEASURE PATTERNS:
N.B. All bass examples (and all bass parts) sound one octave lower than written. This is standard transposition practice for bass violin parts (and for guitar parts).



Score References & Musical Examples Using JABB:


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These are only a few of many possible ways to connect harmonies through bass lines. They are chosen to demonstrate principles rather than to be an exhaustive encyclopedia of patterns. Patterns in 3/4 will require the elimination of one note; patterns in 2 most often consist of the root - followed by the 5th or the 3rd, and we haven’t begun to consider what happens when dealing with odd meters like 5/4 and 7/4.

Good bass lines are strong melodies created in an intimate relationship with an existing melody. Following the principles exemplified by Bach, we want to achieve a degree of independence of voices by choosing lines that most often move contrary to the motion of the melody. But anything, even beautiful contrary motion, can become monotonous if its character becomes too predictable. In order to balance this, occasional passages of oblique or parallel motion need to occur to create contrasting textures. Oblique motion occurs when the bass line remains on one note (pedal tone) while the melody ascends or descends by scale or arpeggio, or in the reverse situation, when the melody remains on one note while the bass line moves in one direction or the other by scale or arpeggio. Parallel motion can be used to good effect when the melody is high enough in the harmonic series not to disappear into the harmonics of the bass notes. Thirds, fourths, sixths, sevenths and ninths in the melody can be effectively treated for short passages with parallel bass lines.

There are a few exceptions to the rule of “roots on the downbeats”. Sometimes it is useful to use a descending arpeggio that ends on the root; 7, 5, 3, 1 (or 7, 3, 5, 1 etc.) (in 4) or 5, 3, 1 (in 3).




Score References & Musical Examples Using JABB:


Click on Play Button below to Play from the Score


Click on Play Button below to Play from the Score


Click on Play Button below to Play from the Score




It is also possible to start a measure with the 3rd descending to the root on the next strong beat; 3, 2, 1, 5 or 3, 2, 1, 8 or 3, 2, 1, flat 5.




Score References & Musical Examples Using JABB:


Click on Play Button below to Play from the Score


Click on Play Button below to Play from the Score



These patterns are often preceded by a measure in which the last note is the seventh of that measure’s chord. In fact, when the last note of a measure is the seventh of the chord, it must lead downward by step, usually to the third of the following chord.



Score References & Musical Examples Using JABB:


Click on Play Button below to Play from the Score



Click on Play Button below to Play from the Score


Click on Play Button below to Play from the Score



There are two circumstances in which the 5th of a chord sounds acceptable on the downbeat. The first is when the bass note is a pedal tone with changing chords above it - one of which has a root a fourth above the pedal tone.



The other acceptable condition for the fifth remaining in the bass is in a passage where the chord in question is approached and left by step.


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Occasionally, the 5th of the chord lands on the downbeat and the line proceeds diatonically upward (in 4), ending on the root.


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Coming Next Lesson: Lesson 3 - Bass Lines (continued)