THEME & VARIATIONS
A theme and variations is a form of music in which the piece begins with a main melody, or theme. This is followed by one or more variations of that melody. A variation is a section of music that is similar to the theme but does not repeat the melody identically.
There are multiple ways in which a composer can alter a theme:
Modulation: Changing from one tonal center to another. Example: C Major to A Major.
Ornamentation: Embellishment of a melody by adding notes or modifying rhythms.
Harmony / Tonality: Key changes or reharmonizing the theme. A theme in a major key can be reharmonized to a minor key or vice versa.
Here is an exerpt from the fourth movement of Schubert’s Quintet in A Major (Trout) for Violin, Viola, Cello, Double Bass, and Piano.
In the first variation, the theme moves from the violin (top line) to the piano (bottom line of second excerpt) and is ornamented. Additionally, the rhythm in the accompaniment is altered.
Here is the theme. Notice the simple accompaniment by the other strings. The piano is not playing.
This is the first variation. Notice how the theme is in the piano part and ornamented with trills. The strings support the ornamentation with triplets in the violin part and arpeggios in the viola part.