Changes

Being the very heart of the sonata form's drama, there are as many variations on this basic principle as there are variations on a plot in classical literature. In the sonata forms of Beethoven, for example, the second key area was often not in the dominant; his "Waldstein" Sonata (Op. 53) is one famous example. Also, in many of Haydn's sonata forms, such as the Piano Sonata in Eb (Hob. XVI:62), the second key area contains exactly the same theme as at the sonata's beginning, but presented in a different guise.  

Being the very heart of the sonata form's drama, there are as many variations on this basic principle as there are variations on a plot in classical literature. In the sonata forms of Beethoven, for example, the second key area was often not in the dominant; his "Waldstein" Sonata (Op. 53) is one famous example. Also, in many of Haydn's sonata forms, such as the Piano Sonata in Eb (Hob. XVI:62), the second key area contains exactly the same theme as at the sonata's beginning, but presented in a different guise.  

Some words of caution are thus in order with the terminology. While textbooks often use the terms "first subject (or theme)" and "second subject (or theme)," they can be misleading and even unhelpful when analyzing real sonatas, and incidentally was not the way that composers conceived of the form. Many sonatas contain many more than two distinct themes, and several contain no recognizeable "second theme," rather musical material of an aphoristic or fragmentary character. Also prevalent in older texbooks is the description of the second theme as being more lyrical, or feminine, in character. This also does not hold true in most real-life examples.

Some words of caution are thus in order with the terminology. While textbooks often use the terms "first subject (or theme)" and "second subject (or theme)," they can be misleading and even unhelpful when analyzing real sonatas, and incidentally was not the way that composers conceived of the form. Many sonatas contain many more than two distinct themes, and several contain no recognizable "second theme," rather musical material of an aphoristic or fragmentary character. Also prevalent in older texbooks is the description of the second theme as being more lyrical, or feminine, in character. This also does not hold true in most real-life examples.

Therefore, what is essential about the exposition is the modulation to a second key, a strong cadence in that key, and a contrast in character between the music of the two key areas achieved by any variety of means. This essential contrast between key and materials is to the sonata form what a conflict is to literature

Therefore, what is essential about the exposition is the modulation to a second key, a strong cadence in that key, and a contrast in character between the music of the two key areas achieved by any variety of means. This essential contrast between key and materials is to the sonata form what a conflict is to literature