MUSIC THEORY

Mod 38

• Subject of the Day: Chord Progression
• Reading Assignment: Textbook pp. 105-119
• Written Assignment: Harmonic Progression (handout)
• Semester Schedule

A perusal of the harmonies of the common practice period (approx. 1600 - 1900) reveals that the tonic chord is most often preceded by a dominant chord or less frequently, a leading tone triad.  Let us designate these chords (V and vii^o ) as first class chords.  The dominant chord is most often preceded by a supertonic triad (second class, since it proceeds to the first class chord) or a subdominant (also second class).  The leading tone triad (1st class) also is most often preceded by either subdominant (2nd class) or supertonic (2nd class).  The subdominant or supertonic usually follows a submediant triad (third class).  The submediant triad is most commonly preceded by the mediant (fourth class).

It is considered Normal Progression  when the chord succession proceeds through the classes in descending order, e.g. vi  -  ii  -  V  -  I  (3rd class - 2nd class - 1st class - Tonic).  Going backward through the classes (e.g. V  -  IV  or  ii  -  vi  or  IV  -  iii ) is Retrogression.  When the chords move toward the tonic but skip one or more classes (e.g. iii  -  IV   or   iii  -  V ), we label that Elision.

The tonic chord is a free chord.  It can follow any other chord or go to any other chord.  The only time the tonic chord is harmonically functional is when it follows a 1st class chord.  Otherwise we ignore the chord in terms of harmonic progression.

Notice that in the 1st class category there are two chords.  If both are used, it is normal progression for vii^o to proceed to V, but a retrogression if V goes to vii^o.  Likewise in the 2nd class category, normal progression is IV to ii, whereas ii to IV is considered retrogression.  Observe that in both cases, normal progression results when the root of the second chord moves down a third.

There are three very common progressions which are not Normal Progression, but are used so frequently that they are considered good progression.  We call these Common Deviations.  V - vi by definition is a retrogression, but is readily accepted as good.  vi - V you may recognize as an elision, but it, too, is acceptable.  Finally, the progression iii - IV sounds okay.  These two chords (iii - IV) are quite often preceded by a vi chord.

If you still have questions, contact Dr. Bartolotta at wbartolo@odu.edu