6

Unit I: Modes and Scales

• Any of the pitches may be asserted as “tonic.”

major form has no tritone

minor form has a tritone with no place to resolve

7

• Only two discrete versions are possible with respect to pitch class.

• Any pitch may be asserted as a “tonic.”

• Many tritones present but few standard resolutions are possible.

9

Scale Mutation

• Transposition: root moves, scale type retained

(see Debussy, Cathédrale mm.14-16, transposes the pentatonic scale)

• Scale Type Changes: movement from Whole-Tone to Pentatonic (both with

Bb pedal)

(see Debussy, “Voiles” m. 44 to m. 45)

• Transposition and Scale change: both of the above occur

very common (see Debussy Cathédrale mm.1-13)

Common-Tone Scale Mutation

• At least one pitch in common between two temporally adjacent scales

(see Debussy Cathédrale m.1 pentatonic has [E] in common with m.7

minor pentatonic)

Also:

==================================

10

Tetrachords and Scale Synthesis

• Break scales into characteristic four note collections

Minor tetrachord:

1st tetrachord in: dorian, aeolian, minor,

and Model B octatonic scales

Major tetrachord:

1st tetrachord of ionian and mixolydian sacles

Phrygian Tetrachord:

1st tetrachord of locrian and phrygian scales

Lydian/Whole-Tone Tetrachord:

1st tetrachord of lydian and whole-tone scales,

2nd tetrachord of locrian scale

Octatonic Model A Tetrachord:

(may be found in any Octatonic scale)

11

Harmonic Minor Tetrachord:

2nd tetrachord of harmonic minor scale

and found in Bartók’s “Hungarian” scales

• Scale synthesis involves conjoining two tetrachords. The interval between the

tetrachords is referred to as the interval of conjunction usually a m2 or M2.

[Tetrachord 1] !m2 or M2" [Tetrachord 2]

• Phrygian mode may be understood as follows:

[Phrygian Tetrachord] !M2" [T7(Phrygian Tetrachord)]or

[0,1,3,5] + [7,8,10,0]

• Atypical combinations such as:

[Lydian Tetrachord] !m2" [T7(Harmonic minor tetrachord)]or

[0,2,4,6] + [7,8,11,0]

may be described as the synthesis of tetrachords characteristic of Lydian

and harmonic minor

====================================================================