10.2 Part Writing, Root Position Triads and Suspensions: Tutorial

Part Writing with Root Position Chords

Part Writing Guidelines

When part writing chords, we combined all of the knowledge we have learned about good horizontal and vertical connections between voices in order to create a set of guidelines for good part writing practices. Following these guidelines helps to ensure that part writing errors are avoided before they are written. Consider the following things when part writing:

• Common tones
  • Retain common tones when possible
  • If there are no common tones, try to move the upper voices in contrary motion to the bass voice.
• Complete vs. incomplete chords
  • A complete chord has all chord members present. Complete chords are preferred to incomplete chords.
  • An incomplete chord is missing a chord member. Most often, the 5th is omitted and the root is doubled or tripled. Chords with tripled roots appear at cadences, not within the phrase.
• General Doubling rules
  • Do not double tendency tones and more active scale degrees (like the leading tone or chordal seventh).
  • Double the root (bass) of the chord in root position major and minor chords (except when going V-vi, in which case the 3rd of the vi chord is most often doubled. See more about the V-vi progression below).
  • Diminished chords are most often used in first inversion with the 3rd of the chord doubled. It is best to avoid root position diminished chords when possible because their interval structure often creates part writing errors like parallel and unequal 5ths with surrounding chords. If a diminished chord must be used in root position, always double the 3rd of the chord to minimize the chances of part writing errors.
• Think horizontally at all times to create smooth lines in each voice, especially in the soprano. Avoid leaps larger than a 3rd, but if a larger leap is used, it should be filled in by step in the opposite direction.
• Resolve tendency tones (like the leading tone). A leading tone in the soprano should always resolve to tonic. A leading tone in an inner voice may move down to scale degree 5, though you should make an effort to resolve it to tonic when possible. Leading tones in the bass resolve to tonic unless they switch voices when moving to another dominant function chord. In that case, they should resolve to tonic in the new voice.
• Check for part writing errors. Always check each chord for doubling and spacing errors and check each chord connection for other part writing errors (like parallel 5ths and octaves). In addition, check that you have spelled the intended chord with the correct notes and accidentals, and that all notes in the chord line up vertically according to their rhythmic placement in the bar.

Part writing guidelines for V-vi or V-VI

The connection between V and vi chords can be problematic because of the creation of parallels between chords, because of a melodic augmented 2nd interval in one of the voices if in a minor key, or because of the inability to resolve the leading tone. Look at the following examples.

In example 1, parallel octaves occur. This happens in both major and minor keys. In example 2a, a melodic augmented 2nd is created by motion from scale degree 7 in the V chord to scale degree 6 in the VI chord. This only occurs in minor keys. You can see in example 2b that the augmented 2nd does not occur in a major key. However, in that example, the leading tone does not resolve to tonic. Doubling the 3rd of the vi chord solves all three of these problems.

V-vi part writing guidelines:

• Scale degree 7 in the V chord moves in parallel motion with the bass, resolving to scale degree 1.
• The other 2 voices move down, contrary to the bass, to the closest chord tones.
• This results in a doubled 3rd in the vi chord, which will resolve the leading tone, avoid parallels, and avoid a melodic augmented 2nd in a voice in a minor key.
• Moving away from a V-vi progression with a double 3rd in the vi chord can also cause problems. Always carefully check for errors between chords.

Summary of part writing steps

1. Write the names of the notes found in each chord using correct doubling and accidentals.
2. Voice the first chord using generous spacing between voices while keeping voices in their respective ranges. Plan to have the soprano move by step. Check for doubling and spacing errors before connecting chords.
3. Connect chords:
   1. If there are common tones, add those in first. Then move each voice to the closest note in the next chord using smooth, stepwise motion when possible.
   2. If there are no common tones, move all upper voices in contrary motion to the bass.
   3. If writing a V-vi progression, resolve the leading tone to tonic, move the other two voices to the closest chord tones in contrary motion with the bass. The third of the vi chord should be doubled.
4. Check for part writing errors.

Part writing with suspensions

To review suspensions, see chapter 7.3 on non chord tones

A suspension is an added non-chord tone that resolves down by step to a chord tone. When part writing using suspensions, follow the guidelines for part writing the chords without the suspensions first, making sure to avoid any part writing errors. Then, add in any suspensions. You cannot use a suspension to avoid part writing errors.

Not all chords can support all types of suspensions. Root position chords can support 9-8 (2-1) and 4-3 suspensions. The 7-6 and 2-3 suspensions are only possible when used over a chord in first inversion.

Summary of part writing with suspensions

1. Part-write the chords without the suspension first, following all part writing steps and guidelines. Check for errors. You cannot use a non-chord tone to fix part writing errors.
2. Locate the voice that will create the correct suspension numbers.
   1. The bass voice in the second chord will form the correct resolution interval with one of the upper voices (the resolution interval is the second number in the suspension label). That voice will get the suspension.
   2. Make sure that the chosen voice can be suspended from the previous chord, meaning that it is coming from a step above in the previous chord.
3. Insert the suspension.
   1. Check rhythm and vertical alignment of beats in the bar.
   2. Choose a tied suspension or an articulated suspension.
4. Label the suspension
   1. Put the non-chord tone in parenthesis.
   2. Write the suspension numbers and SUS label near the suspended note.

Proceed to the theory exercises for guided exercises on part writing root position chords and suspensions.