SOUND PATTERNS

A Structural Examination of Tonality, Vocabulary, Texture,
Sonorities, and Time Organization in Western Art Music

by PHILLIP MAGNUSON

DIATONIC PROCEDURES III

Chapter 18. Tonic Substitutions

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Chapter 19. Dominant Substitutions

18.1 SUBMEDIANT TRIAD

The submediant shares two scale degrees with the tonic triad (^1 and ^3). These are scale degrees of great stability and consequently the submediant can serve as a SUBSTITUTION for the tonic triad. In major keys, the submediant is a minor triad; in minor keys, it is usually a major triad. These substitutions occur in three contexts.

  1. Simple substitutions within a tonic prolongation:

    These will be labeled with the abbreviation "sub". Dominance can be used as a passing chord (bass motion ^6 - ^7 - ^8 or ^8 - ^7 - ^6) between tonic and the tonic substitution.

  2. Substitutions within a subordinate progression:

    The substitutions must also be labeled (sub) in addition to the progression.

  3. Substitutions in an authentic cadence:

    This is called a DECEPTIVE CADENCE (D.C.) and is the third (and final) traditional cadence formula found in the Common Practice Period. If the authentic cadence is like a period in punctuation, and a half cadence is like a question mark, then the deceptive cadence is like an exclamation point!

    Please note that the ^5 - ^1 (Sol-Do) bass motion of the authentic cadence is now ^5 - ^6 (Sol-La). This is only one of several possible scale degree motions in the bass for a deceptive cadence. The soprano is likewise unformulated, and can be several combinations of scale degree motions.

18.2 EXPANDING THE SUBMEDIANT

In major keys, adding a 7th to the submediant does not affect the substitutive function, in spite of the instability this addition lends to the chord. This is due to the fact that all three members of the tonic triad are present (^1, ^3, ^5).

In minor keys, the submediant 7 contains the interval of a M7. As explained before with subdominant 7, M7's simply do not resolve as well as m7's and d7's, and should be avoided.

Putting either the triad or tetrad in 1st inversion also intensifies the substitutive nature since ^1 is in the bass.

18.3 SUBDOMINANT 1ST INVERSION AS A SUBSTITUTION

The subdominant 1st inversion (presented in Chapter 15 as a connection) shares two scale degrees with the submediant (^6 and ^1) and also has ^6 in the bass. Due to these similarities, it can serve as a substitution for the submediant, which, by extension, may also serve as a substitution for the tonic, even in a deceptive cadence. Please note that the subdominant in root position never serves as a substitute for tonic.

18.4 MEDIANT TRIAD IN MAJOR KEYS

The mediant triad in major keys is an unusual sonority. It shares two scale degree with tonic (^3 and ^5), but it also shares two scale degrees with dominant (^5 and ^7). Consequently, it is difficult to pinpoint a strong function for the mediant within prolongations. When the mediant triad is in root position, it can serve as a weak substitute for tonic in first inversion (weak because of the presence of ^7). It is so weak that it should only be used in tonic prolongations, never in cadences.

18.5 MEDIANT TRIAD IN MINOR KEYS

In minor keys, the story of the mediant changes greatly. There are two versions of mediant:

The major mediant (with Te) makes an excellent substitute for tonic, unlike the ambiguous mediant in major keys. This triad works equally well in root position or 1st inversion. The augmented triad (with Ti) will be discussed in the next chapter.

18.6 PICARDY THIRD

The PICARDY THIRD (also known by its French name TIERCE DE PICARDIE) is a Baroque practice of ending the final authentic cadence of a piece in a minor key with a major triad. It is assumed that this major triad sounds more "consonant" than the minor tonic, thus ending the piece more conclusively. Add an asterisk (*) to the left of the major tonic to indicate this special chord.

A true Picardy third only happens at the final cadence of a composition, but it is possible sometimes to find major tonics in interior cadences. Often these are forms of dominance which resolve in the following phrase.

CURRENT VOCABULARY:

Tonic, dominant (7), supertonic (7), subdominant in several positions, leading tone in first inversion, all the 6/4 types, and tonic substitutes (submediant and mediant) [new items in red]

Major keys

Minor keys

ASSIGNMENTS:

ANALYSIS

Describe the phrase design and provide a Roman numeral and structural analysis for the following pieces in Music for Analysis:

  1. Mozart: Sonata, K.545 [#89, CD track #10]
  2. Corelli: Sonata for Violin and Continuo, op.5, no.9 [#93]
  3. Beethoven: Trio, op.1, no.3 [#95] Listen to a performance
  4. Mozart: Sonata, K. 283 [#96, CD track #10]

SYNTHESIS

Add soprano, alto, and tenor lines to this figured bass, and include, with eighth notes only, at least 3 passing tones and 3 neighbor tones (never more than one in any given beat) in the upper three voices. Circle and label the non-chord tones and provide a Roman numeral and structural analysis:

The second chord of the first measure has not been discussed, but the quality and function are readily apparent. The 7th in some of the tetrads cannot immediately resolve down by step; maintain the pitch in the same voice until it can resolve.

To prepare this writing assignment properly, use the notation guidelines appendix, located at Basic Principles of Music Notation, Semester II.


Link to chapters in this unit:
Chapter 19. Dominant Substitutions

Link to previous unit: DIATONIC PROCEDURES II: Expanding the Phrase

Link to next unit: CHROMATIC PROCEDURES I: Moving from the Global Key


Copyright 2008-2009 by Phillip Magnuson.

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