MUSIC THEORY

Mod 39

• Subject of the Day: Harmonizing with Only Soprano Given
• Reading Assignment: None
• Written Assignment: Workbook; p. 59 (Nos. 1 + 2 in 3 voices, Nos. 3 + 4 in 4 voices)
• Semester Schedule

If only a soprano is given, one needs to go through several steps to properly turn the line into a viable 4 voice piece of music.

• Determine the Key                                                                                                                  First you must determine the key of the melody.  Being aware that a key signature can be interpreted two different ways, we need to determine whether the tune is in the major key or the relative minor key.  There are several items that can be searched.  1) Are there any accidentals in the music, typically the leading tone in the minor key?  Remember the leading tone in the minor key is the equivalent of the raised dominant in the relative major key.  Since the dominant is the second most important note in a key, it would not follow that changing it by a half step would give any support to the notion that the key could be the relative major.  2) Also triad outlines could often be detected in a melody.  If the triad outlines are on I, IV, or V (the Primary Triads) of the major key, this would be strong evidence of the key being major.  Likewise if the oultined triads are i, iv, or V of the minor key, the melody is likely minor.  3) A frequency of tonic and dominant tones in either the major or minor could be evidence supporting your choice.
• Supply a Bass Part with Roman Numerals                                                                              After determining the key, supply Roman numerals and a bass part.  To do this you need to consider that each soprano note could be the root of a chord, the third of a chord, or the fifth of a chord.  Making constant reference to the Chord Classification System, develop a good progression.  Next you create a bass part looking  for opportunities to move the bass in contrary motion to the soprano.
• Fill in Alto and Tenor                                                                                                            Plan ahead to be sure there is room for alto and tenor movement.  Once your bass and chord designations are  completed, all that is left is to supply alto and tenor lines to what you have already written.  Be sure that each chord has 2  roots, 1 3rd, and 1 5th.  Also check for leading tone accidentals in minor keys.

This melody has two sharps in its key signature.  That means it is either in D major or B minor.  If it were in B minor, we would expect to see an A# somewhere in the music, because A# is the leading tone in B minor.  One point in favor of D major.  The few skips that are found in this melody seem to also suggest D major.  One skip, the D to A, suggests a D major triad which would be a I chord in D major.  The other skip, A to F# in the second measure, could be part of the I chord, also.  Finally we have another A to F# at the end.  The tonic note, D, appears twice; the dominant, A, is used three times.  The tonic of B minor, B, shows up once;  the dominant, F#, is found twice.  All of these items suggest that the melody is in D major.

Next, we should create a bass part and a chord under each soprano note.  The first note, D, could be the root of a I chord, the third of a vi chord, or the fifth of a IV chord.  We need to make a written or mental note of these three possibilities for later reference.  The second note, C#, could be the root of a vii^o chord, third of a V chord, or fifth of a iii chord.  We can immediately discard the vii^o chord because diminished triads are not used in root position.  Thus, we are left with the two possibilities.  On the following D, the potential chords are the same as the first note.  Going through the rest of the melody in this manner would result in the possibilities shown below.

The next step is to create a progression that follows very closely the normal progression according to the Chord Classification System.  After that is done write the Roman numerals and a bass part following the guidelines for good melody.  One solution could be what is done below.   After that is done use correct voice leading procedures for four voice writing or follow principles for three voice writing.