The Basics

Dominant seventh chords, built on the fifth scale degree (with the leading tone raised in minor), are the only diatonic seventh chords to have a Mm7 quality. Since the interval of a seventh is dissonant by definition, chordal sevenths are tendency tones, and seventh chords require special treatment with regard to the approach and resolution of the chordal seventh. 

Approach and Resolution

In discussing the approach and resolution of the chordal seventh, and the dominant seventh chord in particular, it is useful to think about the chord tones of the dominant seventh chord as their respective scale degrees:

• chordal root: scale degree ^5
• third: ^7
• fifth: ^2
• seventh: ^4

The resolution of the chordal seventh is always down by step, from scale degree ^4 to ^3. There are no exceptions. In this regard, it has a stronger tendency to resolve than even a leading tone within a key.

Coupling the resolution of the chordal seventh with a particular approach creates a linear resemblance to four common NHT’s:

• Passing tone (^5 – ^4 – ^3), as part of a I – V7 – I or V – V7 – I progression.
• Neighbor tone (^3 – ^4 – ^3), as part of a I – V7 – I progression.
• Suspension (^4 – ^4 – ^3), as part of a IV – V7 – I, or ii – V7 – I progression.
• Appoggiatura (^2 – ^4 – ^3), as part of a V – V7 – I, or ii – V7 – I progression.

Root Position Resolution of V7 to I

Resolution of the V7 chord requires handling the two tendency tones, the leading tone and the chordal seventh. If the leading tone is in the upper voice, it must resolve up by step. If both the V7 and I chords are in root position, then either the V7 or the I chord must be incomplete. Incomplete I chords can only appear at cadences.

Complete V7 to incomplete I involves the following scale degree movements (resolution):

• ^4 – ^3
• ^2 – ^1
• ^7 (in soprano) – ^1
• ^5 (root in bass) – ^1 (root in bass)

An incomplete V7 will have the root doubled and the fifth omitted. An incomplete V7 to complete I will involve:

• ^4 – ^3
• ^7 (in soprano) – ^1
• ^5 (not bass) – ^5
• ^5 (root in bass) – ^1

If the leading tone is not in the soprano, its natural tendency can be frustrated. In this case ^7 jumps down to ^5. Do not insert a passing tone between ^7 and ^5. It calls intention to what is a resolution fake out. The resolution of the chord will look like:

• ^4 – ^3
• ^2 – ^1
• ^7 – ^5 (frustrated leading tone resolution)
• ^5 (root in bass) – ^1 (root in bass)

Notice that in addition to the root movement of ^5 – ^1, and the chordal seventh resolution of ^4 – ^3, that the chordal fifth (if present) will always move ^2 – ^1.

Harmonizing Melodies:

• Analyze the melody for scale degrees.
• Figure out possible chords for each scale degree. (Write them below the lower staff.) Only I, IV, and V are permissible for now.
• Choose harmonies for each scale degree (or group, if slower harmonic rhythm). As you choose harmonies, you eliminate harmonies that would create bad progressions (you need to avoid V – IV, in both major and minor).
• Write the bass line according to your harmonic choices (root position chords for now). Check for bad parallels.
• Fill in the inner voices.

Making Voice Leading Reductions:

• Start by analyzing harmonies, and label them with Roman numerals. Circle NHT’s.
• On a grand staff, notate the main chord tones of the bass line as quarter notes (black note heads with stems), with the stems going down.
• Add Roman numeral harmony labels below the bass.
• Notate the essential tones of the soprano voice on the upper staff as quarter notes with stems up. Add the scale degrees of the soprano above the staff (with carets, ^).
  • If there is more than one chord tone in the soprano per harmony, decide which chord tone creates the essential line by trying to connect them to other essential tones. Favor stepwise motion over leaps, although it is possible that there would be more leaps than is usual in four-voice texture. 
  • Remember, you are looking for the essential melodic outline. It will probably not be as interesting as the melody. 
• Pickup notes do not get a stem. Just use a black note head.

Primary Triads

The primary triads in any key are tonic, dominant, and the subdominant. These fit into the T (tonic), D (dominant), and P (predominant) categories, respectively. Some theorists actually refer to the categories as T, D, and S, for subdominant.

In major, the qualities are I, IV, and V (all major). In minor the qualities are i, iv, and V. Sometimes, especially at ends of sections or works, tonic can be major. 

Partwriting Primary Triads

Partwriting depends on the relationship between the triads – specifically the distance between their roots.

Chords that are a 4th/5th apart (fifth-related) will generally involve moving upper voices to the closest chord tones. Usually that involves keeping the common tone in the same voice.

Chords that are a 2nd apart will not have any common tones. You need to be careful not to write parallel P5/8s. The best thing is to move the upper voices in contrary motion to the bass.

Other Partwriting Issues

In minor, you always need to move down to the leading tone (#^7) to avoid augmented melodic intervals. 

Always resolve your leading tone up by step. This is an absolute requirement if the leading tone is in the soprano. It is recommended elsewhere. If the leading tone doesn’t resolve up by step, it will move down to scale degree 5.

Never double tendency tones within a single chord. For now, this means that you will never double the leading tone in a V chord.

Harmonic Cadences

Tonic and Dominant represent opposite poles in the tonal system. Tonic represents your starting point, and your finishing point. Dominant represents the move away from tonic, and predicts its eventual return. Our names for harmonic cadences reflect this, and also take into consideration melodic cadence.

Harmonic motion that ends (a phrase) on the dominant (V) is called a half cadence (HC). 

Harmonic motion that ends with the dominant moving to tonic (V – I) is an authentic cadence (AC). If the harmonic  authentic cadence is accompanied by a conclusive melodic cadence in the top voice, then you have a perfect authentic cadence (PAC, or PA). If the melodic cadence is inconclusive, then you have an imperfect authentic cadence (IAC, or simply AC).

Harmonic motion that ends with the subdominant moving to tonic (IV – I) is a plagal cadence (PC). Plagal cadences occur much less often that authentic cadences. Some people refer to the plagal cadence as the “Amen” cadence, as it is sometimes found at the ends of hymns, after a perfect authentic cadence, where the choir sings A-men.