Form and phrase ANALYSIS

As an example, we shall analyze the form of Chopin’s Prelude No. 17 in Ab major. Also, we shall find all the phrases in prelude’s thematic material.  

The form is five-part rondo (A B A C A) and it contains small auxiliary structural units. We shall find an introduction, transitions and coda. Also, we shall see that the episodes (the material labeled with B and C in the outline) end with codettas. This prelude has quite a melodic character and its phrases can be relatively easily followed. After finding the cadences, the phrases and higher structural units can be determined.

The next figure shows the introduction and the first phase. Measures 1 and 2 form the introduction. There is a half cadence in measure 10. The half cadence ends the first phrase. The first phrase starts after the introduction (at the beginning of measure 3) and contains eight measures. 

Figure: The first phrase in Chopin’s Prelude No. 17 in Ab major

The next figure shows the second phrase which again has eight measures. It ends with the perfect authentic cadence. 

The first and second phrases form together a period. Also, they form the principal of rondo i.e. the material labeled with A in the outline. These two phrases suggest a normative of eight measures per one phrase in this composition. 

Figure: The second phrase in Chopin’s Prelude No. 17 in Ab major

The next figure shows the following sixteen measures of the prelude. They form the first episode of the rondo i.e. the material labeled with B in the outline, together with its codetta and the transition to the principal. 

Measures 19 to 27 make the third phrase. It is an irregular phrase. It has nine measures instead of eight as we expect. The measure 25 is a transposed repetition of the previous measure and we can say that this additional measure is the reason why the phrase has one measure more than we expect. Perhaps, we can imagine that Chopin liked measure 24 so much that he decided to add a transposed repetition of it so that listeners can enjoy even more in it. 

From measure 28 to the first half of measure 32 there is the codetta of the first episode. The codetta reuses material from the cadence and contains two minor plagal cadential progressions. A minor plagal cadential progression is like a standard plagal cadential progression, only it uses the minor triad chord on the fourth scale degree instead of the major one. First, we must imagine the chord progression that occurs in measure 28 and again in the measure 30 as the prolongation of the minor triad chord on the fourth scale degree. Since harmony goes from this chord and then immediately returns back to it, this is a sort of embellished minor triad chord on the fourth scale. 

From the second half of measure 32 to measure 34 there is the transition from the first episode to the principal.

Figure: The third phrase in Chopin’s Prelude No. 17 in Ab major

The next figure shows the fourth phrase which has eight measures. It ends with the half cadence. It is similar to the first phrase. It forms the second occurrence of the principal, which is shorter than the first one.

Figure: The fourth phrase in Chopin’s Prelude No. 17 in Ab major

The next figure shows the following twenty-two measures of the prelude. They form the second episode of the rondo i.e. the material labeled with C in the outline, together with its codetta and the transition to the principal. 

Measures 43 to 50 form the fifth and sixth phrases which are irregular. They have four measures instead of eight as we expect. They end with imperfect authentic cadences. Shorter phrases are raising the tension, announcing the culmination of the prelude that is coming. 

Measures 51 to 57 form the seventh phrase which is irregular. It has seven measures instead of eight as we expect. It ends with the perfect authentic cadence. This phrase, together with the previous two, forms a period. The period consists of two antecedents and one consequent.

Measures 58 to 62 form the codetta of the second episode. Again, the codetta contains two instances of a minor plagal cadence.

Measures 63 to 64 form a transition from the second episode to the third principal.

Figure: The fifth, sixth and seventh phrase in Chopin’s Prelude No. 17 in Ab major

The next figure shows the eighth phrase which has eight measures. It ends with the half cadence. It is similar to the first phrase. It forms the third occurrence of the principal, which is shorter than the first one.

Figure: The eight phrase in Chopin’s Prelude No. 17 in Ab major

The next figure shows the following eighteen measures. The first sixteen measures form the ninth phrase which is irregular. It contains sixteen measures instead of eight as we expect. The end of the prelude is coming and such a long phrase lowers the tension. The chord progression that appears during measures 79 and 80 seems to be too weak for a cadence. It is repeated again in measure 81 and the first half of measure 82. A prolongation of the tonic harmony occurs from measure 82 to the beginning of measure 86. Prolongations of harmony will be explained soon. Prolongation of the dominant harmony follows during measures 86 and 87. It is realized using a cadential six-four chord. The phrase ends with the imperfect authentic cadence (C4 is in the melody) in measure 88. This leaves a listener with a somewhat open-ending feeling. In this phrase, Chopin is delaying the cadence from measure 80, where we expect it, until measure 88. This phrase, together with the previous one, forms a period. 

The last three measures form the coda. 

Figure: The ninth phrase in Chopin’s Prelude No. 17 in Ab major

The following figure shows the results of the form and phrase analysis.

Figure: The results of the form and phrase analysis of Chopin’s Prelude No. 17 in Ab major