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Jazz Theory and Practice

Module 1, a, b, c:

Tetrachords and Scales

B. The basic scales and modes; the major scale family

In the study of Jazz theory there has always been some confusion between the terms “scale” and “mode”. Throughout

this course, the terms will be used interchangeably; for the most part the term “scale” will be used.

The basic keyboard design with seven white notes and five black

notes within an octave dates from early in the 14th century.

The most significant feature of this design; something that we take for granted, is that there are two pairs of white keys with

no black keys in between. This feature produces two different intervals between white notes: whole steps and half steps.

Starting a scale on each of seven possible white notes will produce seven different scales, because each scale contains a

different sequence of whole steps and half steps. This should all be familiar before beginning this course, but as a quick review,

here are those seven different scales, showing the combination of tetrachords, the whole- and half-step patterns, and the

traditional Greek names:

Copyright © 2012 Peter J. Clements

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For most of us, our musical memories are mostly filled with music based on either a major scale or a minor scale. There are

scales in the list above that sound enough like a major scale,

with only one different note, that we can easily hear them as a major scale with one “wrong note”. There are “minor-like”

scales as well. Since the ear seems to hear these relationships, it is useful to group these basic scales into two scale families:

the major scale family, and the minor scale family.

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The Major Scale Family

From the seven modes given above, the first one is what we commonly call the major scale, and the other two that almost

sound like a major scale are the Lydian and Mixolydian scales, for the simple reason that they all begin with two whole steps,

that combine to produce a major third at the beginning of the scale.

If all three scales are written starting on a C, it can be easily

seen, and heard, that the latter two are only different from the major scale by one note:

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All three of these scales have the same tonic note—C—but each will have a unique sound because of the arrangements of whole

tones and half tones. Those arrangements of whole tones and half tones, of course, also generate different tetrachords. It is

easy to hear how the character of the scale comes from the pairing of the tetrachords:

MAJOR: Two major tetrachords give the whole scale a “bright,

happy, major” character.

LYDIAN: The major tetrachord, in the top half, is paired with the tritone hexachord, definitely producing a “mysterious, dissonant”

character.

MIXOLYDIAN: The bottom half is a major tetrachord, and the top half is a minor tetrachord, suggesting a “melancholy, bluesy

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character”. The lowered seventh step is common to almost all

blues styles.

If you were to write out these scales with a key signature, you will see that the Lydian scale with C as the tonic note should

have a key signature of one sharp (like G major) and the mixolydian scale with C as the tonic note should have a key

signature of one flat.

In the music literature, however, especially folksongs and popular music where these modal scales appear, most often

pieces will be found not with the “correct” key signature, but with the key signature of the major scale with the same tonic

note, as in the example above, with accidentals used for the “modal” note. Look at the following example:

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This piece is written in the key signature for F major, but every time the seventh note of the scale is used, it is flattened. The

song could have been written with two flats in the key signature, which would be the “correct” key signature for a mixolydian

scale with F as the tonic note.

There is an important principle here: scale (or mode) and key

signature are not always directly connected. In order to figure out the scale of a certain piece, it is the scale patterns within the

piece that determine the scale(mode) of the piece. It is not unusual for a piece to drift between modes, major and

mixolydian, for example (listen to a familiar Christmas song: The Little Drummer Boy).

Another common scale that belongs to the major scale family is

the Major Pentatonic scale. It can be derived from the major scale by simply omitting the 4th and 7th notes, and notice that

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the first three notes are again two whole steps, forming a major

third:

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An easy major pentatonic scale to find is the one starting on F#.

If you play up an octave on the black keys, starting on F#, the note pattern is exactly the same as the C major pentatonic

above.

There are many good “mixolydian” examples on recordings (in some cases mixed with the major scale):

George Benson: “On Broadway”

“Old Devil Moon” from Finnian’s Rainbow. Music by Burton Lane. Look for Frank Sinatra’s version,

arrangement by Nelson Riddle.

“Inchworm” from the film Hans Christian Anderson. Music by Frank Loesser. Look for the jazz version by John

Coltrane.

Return to the menu, and try the PLAY/SING and WRITE exercises for Module 1b.