Jazz Concepts: Tetrachords Part II

January 30, 2013
MANY YEARS AGO, I WORKED FOR A BANDLEADER WHO WOULD occasionally turn around to the rhythm section and say, “Can you guys, uh … play better?” Even though he was a jerk and our rhythm section was solid, we would still nod and act as if we were bearing down, doing our best to play better. We probably sounded just the same. I learned from experience that musicians don’t play better just because someone tells them to do so.

In contrast to that guy with his unique style of psycho-bandleading, I worked with some very nice bandleaders and teachers along the way, like the Louisville guitarist Jeff Sherman. One lesson that I gathered from Mr. Sherman was extremely useful and cleverly delivered: He told me simply to “play what sounds good.” Actually, he explained that chord/scale theory is helpful, but if I used my ears, I could find the notes that fit a particular chord without analyzing the progression theoretically. He taught me to trust my ears and always go for “what sounds good” first, regardless of music theory. Then he taught me the chord/scale theory to explain why it sounded good.

Mr. Sherman, who still teaches a gaggle of guitar and bass students, suggested that when a new chord appears in a progression, I could just change the notes in my line to fit the sound of the new chord, rather than worry about whether a new scale is (for example) Dorian minor, Mixolydian, or diminished whole-tone. When playing a bass line or solo on a chord progression, the line should just describe the important notes that change from measure to measure.

Take a look at the first four bars of Example 1, an étude based on the harmony of the Tadd Dameron jazz standard “Ladybird.” The solo line starts on the 5th of the Cmaj7 chord (the note G), and moves up in a tetrachord. Remember from last time that a tetrachord is a group of four notes, usually within an interval of a 4th. In this case, the line starts with a major tetrachord (whole-step, whole-step, half-step). You can think of this theoretically as one half of a scale.

In bars 3 and 4, the chords change to Fm7 and Bb7. Starting on the note F, the line moves up and down a minor tetrachord (whole-step, half-step, whole-step). By changing the notes A and B on the Cmaj7 to the notes Ab and Bb on the Fm7 to Bb7, the line accurately describes the change of harmony from Cmaj7 to Fm7. You might have found a similar solo solution by using your ears, even if you had never played this chord progression before.

In bar 5, the line starts on the note B, and moves up to E. This is technically called a Phrygian tetrachord (half-step, whole-step, wholestep), but you don’t really need to worry about that. If it sounds good, it sounds good. Since the four-note line is framed by chord tones (B and E) of the Cmaj7, the line sounds very melodic.

As the étude moves through the harmony of “Ladybird,” in most cases the line starts on the root of each chord and moves up and down four notes. In bars 15–16, the last two bars of the progression (i.e., the turnaround), the chords change every two beats. One elegant solution here is to play a major tetrachord starting on the root of each chord. Since the chords move up in 4ths (Eb7, Abmaj7, Db7), the line follows seamlessly.

By now, you might be thinking that this seems overly theoretical. But music theory is the language we use to describe why something works musically. When you use your ears to find a good-sounding bass line or solo, there is always a way to analyze your choice theoretically and talk about it in theoretical language. The obverse side of this—and a common pitfall for music students— is that bass lines and solos that are only conceived theoretically sometimes sound bad. The best approach is to use your ears, but also use the left side of your brain to understand the theory behind your choices.

Here’s an intuitive way to experiment with tetrachords while super-charging your ability to hear choice notes: Take a chord progression that you know, start on any chord tone, and move up and down four notes of any tetrachord, using your ear to guide you to the best notes. Do this out of time, or at a very slow tempo. It might help to use a play-along track, MIDI track, or the iReal Book to hear the harmony. Play up and down any four notes, and adjust to fit the sound of the chord. Don’t worry about what to call the four notes you are playing; the theoretical name of the tetrachord or scale you are using is just a description. You should train your ears to choose the notes that sound good to you. You can analyze the theory behind the line after your ear guides you to the best notes. On some chords, there might be several combinations of notes that work well.

There are two types of bassists: Some players want to know the precise music theory behind the notes they play, and other players just want to play by ear and feel. There are great musicians in both camps. Whichever type of bassist you are, always heed the advice: “Play what sounds good!”



Visit John Goldsby’s website for sound files, videos, and bassrelated material. johngoldsby.com


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