Music And Theory: Harmony, Dissonance, And Tonality

Music and theory and harmony: A descriptive treatment of harmony and dissonance as they are defined under the principles of tonality.

Harmony is the relation of notes to notes and chords to chords as they are played simultaneously.

Harmonic "patterns" are established from notes and chords in successive order. Melodic intervals are those that are linear and occur in sequence, while harmonic intervals are sounded at the same time. Whether or not a harmony is pleasing is a matter of personal taste, as there are consonant and dissonant harmonies, both of which are pleasing to the ears of some and not others.

Music history tells us that the definition of harmony has evolved over a period of time as different music forms have developed. In the Middle Ages, harmony was simply a two-note combination. During the Renaissance, three-note harmony was popular with the introduction of the triad. The Romantic Era expanded chords into four-part harmonies. The only method or technique for music endings was to resolve into a tonic chord built on the 1st and 5th notes of the scale in that key. Contemporary music has broadened the meaning of harmony to accept dissonant chords that never resolve into tonics of the key.



Basic to harmony is the triad mentioned above. A triad is the most common chord form. It is built on the first, third, and fifth notes of the scale and is symbolized in music notation by the Roman numeral I. A triad built on the second note of the scale would include the second, fourth, and sixth notes of the scale, still keeping one scale degree between each jump. A triad built on the second note of the scale is symbolized by the two lower case "I's," written as ii. Triad chords may be built on all seven notes of the scale (with the eighth note a repeat of the first.) Chord symbols for the triads built on the third through seventh notes of the scale are as follows: iii, IV, V, vi, and vii. Just as the I chord is named the Tonic, the IV chord is also called by the name Sub-Dominant. The V chord is the dominant. And the vii is referred to as the Leading Tone, as it is often used to change (or "lead") into a new key. This organization around tones is known as "tonality."

Tonality provides the basis for the establishment of keys. The I, or Tonic chord, determines the key. For instance, when the Tonic is A, the piece is said to be in the Key of A. Another issue in tonality is major and minor. Pieces built on the tones of the major scale are termed major and those built on a minor scale are said to be in a minor key. Major composers - Schubert, for instance - wrote a variety of music in both major and minor keys. Examples are his quartets in "A minor," "D minor," and "G major," pieces that were melodious and full of modulations from key to key. Some of his more well-known chamber music includes "E major Quartet" and "Allegro in C minor."

Harmony that brings about a concordant or agreeable combination of notes is termed consonant. When chords do not fit into an accepted pattern of harmony, they are said to be dissonant or unstable. Dissonance is often used to create moments of suspense that later resolve into more pleasing tones of consonance. Dissonance is sometimes not considered harmony by some teachers of music, although most pedagogy classifies harmony as dissonant or consonant.

Music is based on structure and order. Harmony, dissonance, and tonality are key elements in that school of thought.

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