View Full Version : Lesson 11 - The Rhythm Section

09-15-2007, 07:48 PM
by Chuck Israels


Lesson 11 - The Rhythm Section


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.)



Writing chord charts for pianists, guitarists, and bass players leaves many decisions in the control of the players. This can be a good thing when the players are skilled and experienced, and when they know the music but, more often than not, it provides less information than what is needed to guarantee a good interpretation.
(Actually, providing a chord chart that contains the entire harmonic matrix of the piece that the arranger uses to write it is almost always too much information for a rhythm section player; inexperienced ones fumble to include everything, creating a mess, and experienced ones can be distracted by the task of editing the information to extract the useful material. That ought to be the arranger’s job.)
The biggest problem posed by this all too common arranger’s practice of using the whole chord- chart as a rhythm section part is that it invites constant playing when the best choice can often be silence. So at the barest minimum, rests and rhythms need to be indicated to insure the integration of a rhythm section part into the overall texture of the orchestration. In some cases, this method can work well, but there is one instance where that method is not a good idea; when writing a bass part it is better to write out pitches rather than chord symbols and rhythmic notation. The notated pitches take less time to write, and they have distinct advantages. They indicate the direction of the line and are easier to read (one symbol at a time instead of two).

Here are some guidelines that can help to create good accompaniments:

The more active the accompaniment, the more it constrains and controls the solo voice, but rhythmically neutral accompaniments soon wear thin. A balance between the two styles allows the most variety. Increasing the melodic and rhythmic character of an accompaniment eventually reverses the foreground/background hierarchy and presents a situation in which the improvising soloist is required to adjust the improvisation to fit with a dominating accompaniment. This can be a good technique that can insure consistency of results in multiple performances of a piece. Ellington’s music abounds with examples of accompaniment becoming dominant foreground, and his soloists became adept at providing appropriate responses to the written “backgrounds”.

Providing a platform for a soloist to create freely developed improvisations requires a more neutral background. Gil Evans’ music provides examples of ways to do this that allow freedom for the soloist while interjecting well developed ensemble passages that frame the moments that are dominated by the improviser.

Here are some suggestions of ways to create effective active accompaniments for the rhythm section and some ways of expanding those ideas into the rest of the ensemble:

The most useful register for piano comping is centered below middle C, roughly from D below middle C to G or A above, for rootless voicings. (Occasional bass notes are useful in filling out the sound at climactic points, or when the movement of the bass line creates attractive counterpoint with the melody.) This “upper bass” register is the range of most effective ensemble impact, the “body” range that makes the band sound full and meaty without being overbearing. Most of the “weight” needs to be on the notes below middle C. Whenever this range is exceeded upward, that encroachment is an intrusion into the acoustic territory in which the human ear is most sensitive. This means that that gesture must be deliberate and the moment for it carefully chosen so as not to compete with the dominance of the lead line. Sometimes colorful interjections in this higher register are useful and appropriate but they are useful in inverse proportion to the frequency of their use. In other words, less is more, and play three times more softly in that register unless there is need for an accompanying exclamation point, in which case, make the point and get out of the way.

Staying in the register above F or G above middle C for the lead line of accompanying piano chords can have multiple detrimental effects. It crowds the acoustic area that singers and instrumentalists need. Even if their notes are below that register, subliminal but colorful overtones need to “ring” in that space. Besides this, the ear’s sensitivity in this range makes continued accompanying sounds wearing and monotonous, forcing the listener to divert energy to mentally “turning them down” in order to maintain attention on the primary voice.

Play or write commentary to the melody, not concerted rhythms. Play or write answers or anticipation to the expected rhythms of the bass notes or else the bass rhythm is either duplicated or forced to a less successful position where too many bass notes will have to be played off the beat in order to be heard as separate from the piano.

Here are some examples of accompanying figures for piano, some of which could be orchestrated for other instruments:


Score References & Musical Examples Using JABB:

Piano comping example - Rhythm Changes - 4 voices. Note balance between on-the-beatchords and syncopations. This example could be orcestrated effectively for 4 trombones(or for 5 saxophones by doubling the lead line an octave lower).

Click on Play Button below to Play from the Score


These examples show an effective idiomatic balance between on-the-beat and syncopated elements. Both are needed to make the music swing.

Click on Play Button below to Play from the Score


The Blues riff figure in the preceding excerpt is a good example of the way application of piano music into the winds sometimes needs modification. The melodic figure in the right hand, combined with the repeated major second in the left hand, works beautifully as a piano figure. The sound of the piano, even without the use of the pedal, rings after the key has been released. There is considerable resonance in the soundboard and body of the piano that gives continuity and elision to the music and helps blend disparate sounds.

Winds are quite different. When the wind player stops producing sound, it stops dead. The articulation and decay are so different that some piano figures require translation in order to be applied to winds. Separation of voices takes effort to be made clear on the piano. So much so that Glenn Gould and Bill Evans styles are recognized for their remarkable ability to achieve this difficult result. The identification of individual voices is far more apparent in winds, so care must be taken to ensure that entrances, exits, and the gestures of the voices are appropriate in each instrumental part.

Here’s how this piano riff “translates” elegantly to a trombone section:


Score References & Musical Examples Using JABB:

Click on Play Button below to Play from the Score


The rhythms in the preceding examples have been designed to work at a fast tempo. A quarter note at 208 would be appropriate. Slow music needs even more rhythmic detail in order to remain lively and interesting. The impression that slow music contains only slow note values is incorrect and counterproductive. When the tempo is slow, many surface rhythms need to be based on a double-time pulse, and accompanying chords must often occur after the bass notes that tend to fall more regularly on the quarter note pulses – answering the bass, staying away from the downbeats and adding a layer of rhythmic subdivision.

Here is an example of a small group arrangement that demonstrates a good balance between regular downbeat pulses and unexpected timing in melodic parts and some of the accompaniment. The drum part includes hints of the double-time pulse, and the figures are integrated into the accompanying texture. Note that the high chord voicings in the piano part occur in momentary spaces where there is no activity in the lead wind parts and are therefore not distractingly intrusive. The first piano chord is voiced to establish the tonality with a sonority that leaves acoustic room for the trombone entrance.


Score References & Musical Examples Using JABB:

Click on Play Button below to Play from the Score


One of the adjustments a listener must make during the progress of a conventional jazz performance is to understand the change from an accompanying role to a solo role in the same instrument. The accompanying sounds have been pushed to the background by the listener’s involvement in following the lead line, so when the accompanying voice moves into a lead role, the listener must shift attention to maintain focus on the primary activity. This shift always takes a few seconds, and there is communicative benefit in anything the performer/composers can do to improve the listener’s chances of recognizing the changing roles more quickly. To this end, it is useful if there is a noticeable change in dynamics, density of activity, and register, when a pianist moves from an accompaniment into a solo. This is difficult to accomplish if the accompaniment has been as busy as, and nearly as loud as, the following piano solo, and it is made doubly difficult if the accompaniment has been in the same register as the solo.

Within a given chord, some voices are more important than others in indicating harmonic direction or in delineating a secondary line. It’s good to remember that “the piano is an orchestra”, and a good orchestral accompaniment would not use all the instruments all of the time, and they wouldn’t necessarily play at the same dynamic level. Bill Evans played chorus after chorus of blues in F, accompanying himself with the five notes between middle C and the A flat below it, one at a time, of course. (I’m not even counting the choruses he performed before bringing his left hand into play at all.) This simple technique left him the option of increasing the density and power of the rhythm by adding two or three more notes to the accompaniment chords and striking them more often when he wanted to communicate an increase in musical energy. If a pianist enjoys the variety and shift in energy level achievable by this technique, might not other soloists also benefit from accompaniments (improvised or written) that were designed this way?

There is another implication of the hierarchy of “voice importance” that’s particularly applicable to the piano. When harmonized passages are played by instrumental choirs, the players, according to their sensitivity and training, control the dynamics and pitch nuances of each voice in the chord. More important voices get special emphasis while secondary “coloristic” notes in the lines get more subtle treatment. There are pianists who use the sensitivity of the piano keyboard with considerable expressivity during their solo passages. Some of these same musicians have a tendency to forget variety of touch when creating a chordal accompaniment. All the fingers strike the keys with the same intensity. Sometimes that’s appropriate and sometimes not. If the notes A@/G# below middle C along with D and E above it constitute a B flat chord, then the E welcomes special emphasis, and the A@ probably needs a legato connection to the G or G flat that is likely to follow in that voice in the next chord. If those notes are functioning as an E7, then the D is more important and the G# may be crossing over the A above it, landing on a coloristic ninth (B$) on the following chord. This creates a different set of articulation and dynamic tendencies, just one example of the variety of possibilities that exist every time the harmony moves in a jazz accompaniment.


Score References & Musical Examples Using JABB:

Click on Play Button below to Play from the Score


The role of a piano in a big band is dramatically less powerful in relation to the full band than it is to a small group, and that sets up a different set of conventions. Extremes of register are sometimes necessary just in order to be heard. Basie set a classic example by his impeccably timed minimalist approach, and Ellington made occasional great use of cascading romantic figures which were set in remarkable textural contrast to the prevailing ensemble sound. Both of these masters of the art “wrote themselves out” for long periods when there was a competing ensemble texture to which the piano could only add confusion.

The existence of successful “band choir” accompaniments in the octave above middle C does not change the situation for the piano. The trumpets, flutes and clarinets that sometimes provide accompanying lines in this register, have acoustic properties that are markedly different from those of the piano. For one thing, when you stop blowing into a wind instrument, the sound stops. When you lift your hands and feet from a piano, it continues to ring, perhaps softly but still perceptibly. This is a wonderfully useful characteristic of the piano sound, but it does tend to swamp the harmonic space of instruments and voices that the piano may be accompanying. Besides this element of the piano’s sound envelope, there is the obvious fact that a piano must be struck repeatedly in order to maintain even a quiet level of sound over a period of a few measures, whereas wind instruments can sustain a series of notes over a similar period without re-articulation. This is a significant difference and it gives the piano the edge in the percussive attack department, rendering its lines particularly rhythmically incisive, but the advantage goes to the winds when smoothness and neutrality are required. It can be interesting to orchestrate against these tendencies, but that does not negate the fact of their existence or effect.

ONE OTHER THING: it’s impractical to try to substitute for missing instruments. Better leave them to our imagination. If there’s no bass player, just play the piano part as beautifully as possible, adding roots when they are convenient or necessary. The piano makes a poor substitute for a “walking” string bass. The attack and decay are different, and few pianists can control the effect without a lot of practice. Trying to imitate Ray Brown’s propulsive energy by anticipating the bass notes only makes the music edgy. Besides, even as loud as Ray can be, the bass register of the piano is twice too loud if the same force is applied. Would a pianist attempt to play the drum part if the drummer were missing?


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Coming Next Lesson: Lesson 12 - The Rhythm Section (continued)