MORE MUSICAL FORM

This page is a supplement for The Complete Musician: Chapters 15 - 16

All the way back in Music Theory II, we learned about the most basic building blocks of musical form (in the context of western classical and folk music traditions). This included the phrase (a self-contained musical event ending in a cadence), and the different types of cadences (Perfect Authentic, Imperfect Authentic, Half, Plagal, and Deceptive). If any of this feels rusty, you should go back and review the MUSICAL FORM WEBPAGE now.

THE MUSICAL PERIOD

A PERIOD is a unit of (usually two) musical phrases (a typical phrase being approx. 4 measures) where the first phrase is considered harmonically weaker (usually ending on a H.C. or an I.A.C.) and the second phrase is harmonically stronger (usually ending on a P.A.C.). Some periods have more than two phrases. The first, weaker phrase is called the ANTECEDENT PHRASE (think of this phrase like a question) and the second, stronger phrase is called the CONSEQUENT PHRASE (think of this phrase like the answer). The phrases in periods can end with any type of cadence, but they mostly follow the rules above. There are also periods and other forms that consist of more than two phrases. When identifying a period or another formal structure, we usually consider both its harmonic content (cadence and relationship between the chords at the beginning and end of the phrases) and its melodic content (if the melodies of the phrases are similar or dissimilar to one another).

TYPES OF PERIODS

INTERRUPTED PERIOD

This is a harmonic reference. The Interrupted Period’s first phrase will end with a H.C. and the second phrase will start with a tonic chord.
Phrase 1 __________ H.C. // Phrase 2 I __________

CONTINUOUS PERIOD

This is a harmonic reference. The Continuous Period’s first phrase will end with a H.C. and the second phrase will start with a V chord.
Phrase 1 __________ H.C. // Phrase 2 V __________

SECTIONAL PERIOD

This is a harmonic reference. The Sectional Period’s first phrase will end with an I.A.C. of some type and the second phrase will start with a tonic chord.
Phrase 1 __________ I.A.C. // Phrase 2 I __________

PROGRESSIVE PERIOD

This is a harmonic reference and is used to describe a period where the key of the piece is changing/modulating. The Progressive Period’s first phrase will end with a H.C. or I.A.C. and the second phrase will end with an A.C. in a new key (somewhere outside the original tonic).
Phrase 1 __________ H.C. or I.A.C. // Phrase 2 __________ A.C. IN NEW KEY

PARALLEL PERIOD

This is a melodic reference. The Parallel Period’s first and second phrases are comprised of melodically identical or similar material.
Phrase 1 _____a_____ // Phrase 2 _____a or a’_____

CONTRASTING PERIOD

This is a melodic reference. The Contrasting Period’s first and second phrases are comprised of melodically contrasting/dissimilar material.
Phrase 1 _____a_____ // Phrase 2 _____b_____

When describing periods, we use both harmonic and melodic words to define the form. For example, a period with a Phrase 1 ending on V and a Phrase 2 starting on I with similar melodic material would be identified as a parallel interrupted period.

MORE COMPLICATED STRUCTURES

Not all western classical music is composed to be as straight forward and symmetrical as the period descriptions above. Because of the varieties and nuances of phrases and phrase groupings, music theorists have developed other labels to describe regularly-occurring but uneven types of period-like structures. Remember that form is not a constant and that you will encounter many examples of music that does not fit into the labels above or even below. Because these structures are larger, they also have more variety of phrase types that fit each label.

DOUBLE PERIOD

The Double Period combines two periods back-to-back and usually consists of four phrases. Phrase 1-3 finish with a weak cadence while only Phrase 4 is completed with a strong cadence. Examples include:
Phrase 1 _____a_____ H.C. // Phrase 2 _____b_____ I.A.C. // Phrase 3 _____a_____ H.C. // Phrase 4 _____b’_____ P.A.C. //
Phrase 1 _____a_____ H.C. // Phrase 2 _____a’_____ I.A.C. // Phrase 3 _____b_____ I.A.C. // Phrase 4 _____b’_____ P.A.C. //

REPEATED PERIOD

The Repeated Period features two periods back to back that share structure and material. This differs from the Double Period in that there is a strong cadence at the end of both periods (not just the second period).
Phrase 1 _____a_____ H.C. // Phrase 2 _____b_____ P.A.C. // Phrase 3 _____a_____ H.C. // Phrase 4 _____b’_____ P.A.C. //
Phrase 1 _____a_____ I.A.C. // Phrase 2 _____a’_____ P.A.C. // Phrase 3 _____a_____ I.A.C. // Phrase 4 _____a’_____ P.A.C. //

ASYMMETRICAL PERIOD

The Asymmetrical Period features three phrases where two are similar to each other (either aab or abb).
Phrase 1 _____a_____ H.C. // Phrase 2 _____a’_____ I.A.C. // Phrase 3 _____b_____ P.A.C. //
Phrase 1 _____a_____ H.C. // Phrase 2 _____b_____ H.C. // Phrase 3 _____b’_____ P.A.C. //

SENTENCE

The Sentence is a specific type of period that is almost always eight measures long. In this structure, the first half is presented as two short, 2-measure ideas that are interrelated (either an identical repeat or a similar/sequenced restatement), followed by a contrasting 4-measure phrase. This structure carries a 1:1:2 ratio and is very typical of genres of folk music through western classical music through modern popular music.
Subphrase 1 __a__ // Subphrase 2 __a’__ I.A.C. // Phrase 3 _____b_____ P.A.C. //

PHRASE GROUP

A Phrase Group is a string of phrases (usually three or more) that all end with weak cadences. This can appear to be an asymmetrical period but the difference is that the asymmetrical period finishes with a strong cadence while the phrase group has a feeling of aimlessness, often ending unsettled on a H.C.
Phrase 1 _____a_____ H.C. // Phrase 2 _____a’_____ H.C. // Phrase 3 _____b_____ H.C. //

PHRASE CHAIN

A Phrase Chain is similar to a phrase group but in the chain, the melodic content is different in each phrase. The phrase chain also ends unsettled on a H.C.
Phrase 1 _____a_____ H.C. // Phrase 2 _____b_____ H.C. // Phrase 3 _____c_____ H.C. //

QUIZ YOURSELF

Test out your understanding of phrases and periods by analyzing the following two-page piano score (we looked at this piece once before in Music Theory I).

Listen to the audio to help you hear the similarities and contrasts in the melodic content as well as hear the cadences tonally.

• Analyze the piece for key/tonality (it is in two major keys)

• Divide the piece into phrases (there are more than 10 but less than 15)

  • Using Roman numerals, analyze at least the last two chords of each phrase (for cadence) as well as the first chord of the next phrase

  • Label the cadences (P.A.C., I.A.C., H.C., P.C., D.C.)

  • Label each phrase with a letter based on its melodic content. The first phrase should be labeled a. If the second phrase is different, it’s b … if it’s identical, it’s a and if it’s similar but not identical, it’s a’ (“A prime”). When earlier melodic material comes back later in the music, it should get the same letter as it did at the beginning.

• Based on the pattern of phrases, group them into periods where appropriate. Remember that not all periods consist of two phrases.

  • Label the period groupings with their melodic (parallel/contrasting) and harmonic (interrupted/continuous/sectional/progressive) type

  • Modified periods do not need a “type”

• For more practice, create a Formal Diagram to display a graphic analysis of the piece (compare to the one at the bottom of the page)

When you are done, scroll down to the bottom of the page for the answers!

Analysis below …