Musical Intervals, Consonance, Dissonance, and Chord Construction

Consonance and Dissonance in Musical Intervals

  • Definition of Consonance: An interval is defined as a consonance when it produces a feeling of rest, sounding pleasing and agreeable to the ear.

  • Definition of Dissonance: An interval is defined as a dissonance when it creates a feeling of unrest, sounding less agreeable and unrestful.

  • Interval Classifications (built sequentially from a root note, such as C):

    • Consonant Intervals:

    • Prime (1st)

    • Third (3rd)

    • Fourth (4th)

    • Fifth (5th)

    • Sixth (6th)

    • Octave (8th)

    • Ninth (9th)

    • Tenth (10th)

    • Dissonant Intervals:

    • Second (2nd)

    • Seventh (7th)

  • Auditory Rule for Basic Intervals: Among the intervals spanning from the Prime to the Tenth, all intervals function as consonances with the explicit exception of the interval of the second and the interval of the seventh.

The Structure and Function of Chords

  • Definition of a Chord: A chord consists of three or more different tones sounded simultaneously.

  • Basis of Three-Part Harmony: Three-part vocal and instrumental harmony relies directly upon the construction and progression of chords.

  • Classification of Chords: Just like individual intervals, chords are categorized as either consonant or dissonant based on the quality of sound they produce.

  • Aesthetic Importance of Dissonance:

    • Music comprised strictly of restful, consonant chords becomes monotonous, just as life becomes monotonous if every experience is completely smooth and restful.

    • Dissonant chords serve a critical artistic purpose in composition, providing necessary dynamic tension, variety, and harmonic interest in good music.

Construction of the C Major Chord


Sheet music showing intervals, consonance, dissonance, chord theory, and C chord memory drills

  • General Rule for Chord Building: A chord can be constructed starting on any note and is typically built by stacking intervals of a third above the root note.

  • Building the C Major Chord:

    • Root note: C

    • Scale degrees used: First (11), third (33), and fifth (55) tones of the C major scale.

    • Corresponding solfège syllables: Do (1st tone), Mi (3rd tone), Sol (5th tone).

    • Pitch components: C (1 / Do), E (3 / Mi), G (5 / Sol).

C Chord Memory Drill and Sight-Reading Exercises

  • Pedagogical Purpose: Practice singing chord tones consecutively as a preliminary step prior to attempting simultaneous three-part vocal harmony.

  • Extended Chord Range: The upper octave C (upper Do) is added as an essential constituent tone of the chord drills.

  • "C" Chord Memory Drill Pattern:

    • Sequence 1: Do - Mi - Sol - Do

    • Sequence 2: Do - Sol - Mi - Do

    • Sequence 3: Do - Mi - Sol - Do

    • Sequence 4: Sol - Mi - Do

  • Practical Application: Vocal exercises utilize variations of these core triad tones (Do, Mi, Sol) across different rhythms and sequential arrangements to build sight-reading fluency and intonation accuracy.