A Survey of Music Theory for the College Classroom: Diatonic Harmony

Texture, Voice Leading, and Counterpoint

Texture

Prior to our study of two-part counterpoint and part-writing, we will briefly survey the basic textures found in music. Texture is one of the basic elements of music, along with rhythm, melody, harmony, dynamics, articulation, register, and timbre. When you describe the texture of a piece of music, you are describing the density of the music, or how much is going on in the music at any given moment. In some styles and cultures, texture can change dramatically within a single musical work.

The four textures in music include the following:

  • Monophony – an unaccompanied melodic line – a melody sounding by itself [monophonic].
  • Heterophony – simultaneous performance of two or more melodic variants of the same melodic line [heterophonic].
  • Homophony – multiple voices moving homorhythmically (at the same time), or a melody accompanied by chords [homophonic].
  • Polyphony – two or more simultaneous but somewhat independent lines that have distinct melodies and rhythms [polyphonic].

Voice Leading and Counterpoint

Voice leading refers to the ways in which harmonies are created by the motions of two or more separate but complementary lines in a musical texture. Understanding voice leading greatly aids the understanding of western music. We will begin our study of voice leading by learning to compose simple melodies paired with tonal bass lines.  

Counterpoint is the art of combining two or more musical lines into a coherent whole and is perhaps the most significant item that distinguishes the Western art music tradition. The most important lines in tonal music are the melody and the bass. The inner voices complete and support the harmonies suggested by the melody and the bass line. These practices are in part based on the ancient practice of writing species counterpoint, which developed several hundred years ago. In species counterpoint a second voice is added to a cantus firmus (Latin for “fixed melody”) either above or below the original melody. 

Vocal Ranges for Part-Writing

The following ranges are to be followed when writing two-part counterpoint for this chapter, as well as for part-writing in an SATB texture.

vocal ranges for part writing

First Species Counterpoint

Adding a melody to an existing tonal bass line or adding a bass line to an existing tonal melody is a fundamental skill in music. Learning to write basic counterpoint has been a vital part of theory and composition instruction for several hundred years in the Western music tradition. We will freely adapt the rules of strict voice leading practices in traditional first species counterpoint and apply them to writing tonal melodies and bass lines. 

The Four Types of Motion

There are four types of motion that can occur between two voices – parallel motion, contrary motion, similar motion, and oblique motion. All these types of motion can be used when writing counterpoint, but contrary motion is especially valuable in maintaining the independence of the voices and is a hallmark of contrapuntal writing.

  • Parallel motion happens when two voices move in the same direction while keeping the same interval between them. Parallel thirds and sixths are commonly encountered in tonal part-writing. Parallel fourths are also occasionally encountered in this style. Parallel fifths and octaves are to be avoided.

parallel motion

  • Contrary motion results when two voices move in opposite directions. Contrary motion between the soprano (melody) and bass lines should be sought whenever practical. 

contrary motion

  • Similar motion occurs when two voices move in the same direction, but by different intervals.

similar motion

  • Oblique motion ensues when one voice is stationary, while the other voice moves toward or away from it. 

oblique motion

Basic Rules and Traditions

When adding a soprano melody to a tonal bass line or when writing in an SATB texture, you should pay special attention to certain traditions that have evolved over the past few hundred years.

  • Final Note – The final notes of the melody and bass should occur on a strong beat.
  • Chord Member – Each melody note should fit in the chord that is harmonizing it. 
  • Steps – The melody should feature mostly conjunct (stepwise) motion, have a single high note (focal point), and should end with a re – do (\(\hat{2}\) – \(\hat{1}\)) or ti – do (\(\hat{7}\) – \(\hat{1}\)).
  • Leaps – Melodies can feature some leaps, but certain leaps are to be avoided.
  • Intervals to avoid are the +2, +4, m7, M7, and intervals larger than an octave.
  • Leaps of a fourth or larger are to be followed by a step in the opposite direction.
  • No more than two leaps should be used in a row, and typically these will outline a triad.
  • Leading Tone – The leading tone should progress to the tonic unless it is part of a descending \(\hat{1}\) – \(\hat{7}\) – \(\hat{6}\) line.
  • Repeated Notes – A single repeat of a melody note is allowed. For example, it is fine to have two C’s on successive beats.
  • Independence – The bass and soprano lines must be independent of each other. They should not move in parallel motion (thirds and sixths) for more than a few notes. Do not allow the lines to move in parallel octaves, parallel fifths, hidden fifths/octaves, or otherwise violate the rules of voice leading. 
    • Identify the intervals between the soprano and bass and write that number above the staff. This provides a quick check against voice leading errors and excessive use of parallel thirds and sixths. 
  • Consonances – Emphasis should be placed upon thirds, sixths, fifths, and octaves. The interval of a second should be avoided, and the interval of a fourth against the bass will be introduced in second inversion part-writing.
  • Minor Mode – The melodic minor scale should be used when in the minor mode.
  • Distance and Crossing – The voices should be within about 2 ½ octaves and should not cross.
  • Final Notes – Assuming a V-I progression in the bass at the end of the example, the final two soprano notes should be scale degrees \(\hat{2}\) – \(\hat{1}\) (re – do) or possibly scale degrees \(\hat{7}\) – \(\hat{1}\)  (ti  do). This is also true in the V-vi (V-VI in minor keys) deceptive progression and deceptive cadence.

Adding a Melody to a Tonal Bass

The first step to harmonizing a given tonal bass line is to analyze the bass line with Roman numerals. The second step is to determine what notes can go in the melody. This can be done by spelling the various triads that can be used to harmonize the bass line. Because of the special rules that surround part-writing seventh chords, we will avoid those for now. We will also only use bass lines comprised of the roots of root position chords. In the following example, all the possible triad spellings that include the notes in the bass line are listed, but we will only use the ones in root position at this stage.

adding a melody to a tonal bass

The last step is to create a melodic line that conforms to the conventions expressed in this text. You can write above the staff the numbers for the simple intervals that occur between the bass and soprano as a check for good voice leading. Any time you have a 5 or an 8, you should check for the errors such as parallel fifths and octaves, direct fifths and octaves, hidden fifths and octaves, and unequal fifths, all of which are illustrated in the Root Position Part-Writing chapter.

adding a melody to a tonal bass 2

You should always play your two-part compositions and SATB part-writing examples at the piano because doing so will allow you to detect errors and will also help develop your piano, aural and theoretical skills.

Adding a Bass to a Tonal Melody

Just as a melody can be added to an existing bass line, a bass line can be added to an existing melody. The bass is the harmonic generator or foundation in Western music, and the notes in the bass voice will most often be the root or third of a chord and sometimes the fifth or the seventh. For our initial examples, the bass line will consist of the roots of root position chords. The charts of harmonic progression should always be of foremost importance when harmonizing a melody. Random successions of chords are not progressions!

The first step is to analyze a melody to determine what chords can harmonize it. Each melodic note can be the root, third or fifth of a triad. Because of the special rules that surround part-writing seventh chords, we will continue to avoid those.

adding a bass to a tonal melody

The second step is to carefully choose a progression that conforms to the charts of harmonic progression set forth earlier. Bass lines in root position will typically feature more leaps than the average melody. Later, we will use first and second inversion chords to smooth out the bass line and to add variety. Always remember that the goal for our progression is the motion from V to I. In the next chapter we will learn how to complete the inner voices of an SATB texture. 

adding a bass to a tonal melody 2

Tips for Adding a Bass to a Melody

You must always consider the chart of harmonic progression when adding a bass to a melody. For the assignments in this chapter we are only using root position chords and we will avoid the viio chord.

  • Scale degrees \(\hat{1}\), \(\hat{3}\)\(\hat{5}\) can be harmonized using I (i), vi (VI), and iii (III) chords. The most common harmonization by far would use the I (i) chord.
  • Scale degrees \(\hat{2}\) and \(\hat{7}\) can be harmonized using V and viio chords. The most common harmonization would use the V chord.
  • Scale degrees \(\hat{2}\), \(\hat{4}\), and \(\hat{6}\) can be harmonized using the ii (iio), IV (iv), and vi (VI) chords. The supertonic and subdominant chords will be more common.

We will learn more about the use of the viio chord, first inversion triads, second inversion triads, and seventh chords later in the semester. These options will increase our range of chord choices.

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