6.4 Contrasting Periods

Modified slightly from Wikipedia

"Coventry Carol" is performed in its entirety above on the left by the Drake University Chamber Choir and excerpted in the music notation on the right. The first two phrases of the carol form a contrasting period in that the melodies of the phrases are not similar to each other (unlike the phrases on previous pages). As with all periods, the first cadence (half) is weaker than the second (Perfect Authentic), and as on page 6.2 the half cadence and subsequent return to tonic constitute an interruption which is notated by double slashes below the staff.

Another contrasting interrupted period appears at the beginning of Mozart's piano sonata K 332. In the video below the first cadence is labeled "HC" for half cadence even though it ends with vii°6 (with an F pedal) and not V. Since vii°6 is similar to V and V7--it contains the leading tone and shares all three notes with V7--it is said to have a dominant function. That is, it leads to I.

The music below also has an example of a phrase extension. The consequent at first sounds like it will end at the beginning of measure 1 of the second system, but by beat 2 it is clear that Mozart has "tricked" us and has extended the phrase for another 5 measures. The phrase extension creates an asymmetric period, or a period in which the phrases have a different number of measures.

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