Science Fair Project Encyclopedia
A nonchord tone, nonharmonic tone, or non-harmony note is a note in a piece of common practice music which is not in the chord that is formed by the other notes; for example, if a piece of music is currently on a C Major chord, the notes CEG are members of that chord, while any other note played at that time is a nonchord tone. While such tones are most obvious in homophonic music, they can occur in contrapuntal music as well.
A nonchord tone is a dissonance and is required to resolve to a chord tone in conventional ways. If the note fails to resolve until the next change of harmony, it may instead create a seventh chord or extended chord. While it is theoretically possible that for a three-note chord there are (in equal temperament) nine possible nonchord tones, nonchord tones are usually in the prevailing key.
The following list is not exhaustive, but identifies the most common types of nonchord tones.
- An anticipation occurs when a note is played before the chord to which the note belongs to and resolves when the "anticipated" chord is reached:
- A neighbor tone or auxiliary note is a nonchord tone which is preceded by a chord tone directly above or below it and resolves to the same tone:
- A passing tone or passing note is the nonchord tone of a part which had started at one chord tone and moved up or down through one (or more) nonchord tone and resolving to another chord tone (possibly of another chord, often of the same chord):
- A suspension occurs when the harmony shifts from one chord to another, but one or more notes of the first chord are temporarily held over into the second in which they are nonchord tones before resolving to a chord tone:
Suspensions may be further described using the number of the interval forming the suspension and its resolution; e.g. 4-3 suspension, 7-6 suspension. Most suspensions resolve downwards, the example shown above, a 7-8 suspension, is a rare example of an upwards resolution. A suspension must be prepared with the same note (in the same voice) using a chord tone in the preceding chord; otherwise it is an appoggiatura. The notes are often tied, but this is optional.
- For an audiovisual illustration of the concept of harmonic suspension, visit external link suspension and pedal point.
- An escape tone is a movement by step in the opposite direction of the harmonic motion in that voice:
Another form of nonchord tone is a pedal point or pedal tone or note, almost always the tonic or dominant, which is held through a series of chord changes. The pedal point is almost always in the lowest voice (the term originates from organ playing), but it may be in an upper voice; then it may be called an inverted pedal.
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details