Chapter 5 - Harmonic Organization 1: Intervals, Triads, and Seventh Chords

  • Harmony - The way notes are simultaneously sounded, creating a vertical element to music.
  • Counterpoint - A single melody line or linear voice added to another line or voice.

Intervals

  • Interval - The distance between two pitches.
    • They can be melodic or harmonic.
    • The exact interval size is described by quantity and quality.
    • Quality - Expressed by a number and determined by counting the distance between one letter name and the next letter name.

Identifying Interval Quality

  • All intervals built from the tonic up to notes within a major scale are either major or perfect.
  • Perfect intervals
    • Unison
    • Perfect fourth
    • Perfect fifth
    • Perfect eighth
  • Major intervals
    • Major second
    • Major third
    • Major sixth
    • Major seventh
  • A minor interval is one-half step smaller than major.
  • Diminished interval - An interval that is one-half step smaller than perfect or minor.
  • Augmented interval - An interval that is one-half step larger than major or perfect.
  • Enharmonic intervals - They sound the same but are spelled differently and function differently.
  • Doubly augmented interval - When a major or perfect interval is made one whole step larger without changing the letter names of the pitches.
  • Doubly diminished interval - When a minor or perfect interval is made one whole step smaller without changing the letter names of the pitches.
If-Then Intervals
  • If the top note is in the major key of the bottom note, then it is major or perfect.
  • If the top note is a half step lower than the diatonic note would be, then it is a minor or diminished interval.
  • If the top note is a half step higher than the diatonic note would be, then it is an augmented interval.
  • If an interval is perfect, then both top and bottom pitches are in the other’s major key.
  • If the same accidental is added to both upper and lower pitches, then the interval remains the same.
  • If an accidental is added only to the bottom pitch, then the accidental has the opposite effect than when added to the note above:
    • If a flat is added to the lower pitch, the interval is larger.
    • If a sharp is added to the lower pitch, the interval is smaller.
  • If the lower notes doesn’t represent a standard key, then determine what the interval would be without the accidental and adjust.
  • Simple intervals - Intervals that are one octave or smaller in quantity.
    • They are expanded to a compound interval by adding seven
  • Compound intervals - Intervals that are larger than an octave.
    • They are reduced to a simple interval by subtracting seven.
  • Inverted intervals - Intervals are inverted by transferring the lower note an octave higher or by transferring the higher note an octave lower.
    • Major intervals invert to minor intervals.
    • Augmented intervals invert to diminished intervals.
  • The rule of nine - When any simple interval is inverted, the sum of the ascending and descending intervals must add up to nine.
    • A second inverts to a seven.
    • A third inverts to a sixth.
    • A fourth inverts to a fifth.
  • Consonant intervals - Stable
  • Dissonant intervals - Unstable, the impression of activity or tension.
  • Resolution - The motion of the dissonant interval to the consonant that acts as its goal.
  • Within any four-part composition, these intervals may exist:
    • A-S, Alto and Soprano
    • T-S, Tenor and Soprano
    • T-A, Tenor and Alto
    • B-S, Bass and Soprano
    • B-A, Bass and Alto
    • B-T, Bass and Tenor

Triads

  • Chord - A group of pitches that forms a single harmonic idea.
  • Triad - A three-note chord made up of two intervals stacked in thirds.
  • Root - The lower note of the chord.
  • Third - The middle note because it’s an interval of a third above the root.
  • Fifth - The upper note, it’s a fifth above the root.

Building Triads

  • Tertian harmony - Harmony built on thirds.
  • To build a triad:
    • Build the snowman in thirds above the root.
    • Identify the quality of the lower third as a major or minor.
    • Identify the quality of the fifth as perfect, diminished, or augmented.
    • Identify the chord with the pitch name letter (the root of the snowman).
    • Identify the quality of the triad