Let’s look at the second section of the Mozart theme to see if we can identify these elements in the score.Video betweenAnd let’s hear the “score” performance of this first section again, with the addition of this thematic and harmonic information on the score:Video betweenWe’ve been listening to an electronic rendering of the Mozart theme, so that we could see in the score which notes were sounding, while also taking in additional information about thematic content, phrase structure, and chord progressions. Even still, we can hear that this is a happy tune! (And it’s memorable . . . as we’ll see later, when we investigate “relevant tangents.”)Needless to say, the theme sounds much better in a real performance. And the twelve variations that follow the theme showcase Mozart’s improvisatory imagination with their great variety. For our purposes, we’ve been listening closely to the Mozart theme because it provides a “textbook example” of rounded binary form. And that will allow us to draw connections between rounded binary form and the more sophisticated and elaborate sonata-allegro form, to which we will devote considerable attention in the lessons that follow. Right now, though, let’s meet the members of the Pennsylvania Woodwind Quintet. This will acquaint us with four woodwind instruments and one brass instrument, all five of which are important members of the symphony orchestra.The Classical symphony orchestra was considerably expanded from the Baroque orchestra. While some Baroque orchestras had their complement of woodwinds and brass, the role of these instruments was less pronounced than it would become in the Classical era. And, in the case of the clarinet, the instrument only joined the orchestra during the Classical period.The woodwind quintet of today—most frequently, flute, oboe, clarinet, French horn, and bassoon—did not exist during the Classical era. But chamber works by Haydn and others suggested the viability of such small groups of instruments. Unlike the homogenous nature of the string quartet, the woodwind quintet brings together instruments of divergent character and sound.Let’s meet our musicians and their instruments:We’ll soon listen to the Pennsylvania Woodwind Quintet perform Haydn’s Divertimento in B-flatmajor, the first movement of which is a sonata-allegro form. As we’ll be able to hear, sonata-allegro form shares much in common with rounded binary form. Before we listen, let’s look at a brief comparison between the two forms:
Rounded Binary Form:||: A :||: B A’ :||||: I – V :||: X – V, I – I :||||: i – III :||: X – V, i – i :||Sonata-Allegro Form:Exposition Development Recapitulation||: A :|| B A’ ||||: I – V – V :||: X – V, I – I ||||: i – III – III :||: X – V, i – i ||On the face of it, the most evident difference between the two forms is that we have named the sections of sonata-allegro form:Exposition, Development, and RecapitulationMore to the point, though, the dimensions of the form are greatly increased. And significantly, there are now subsections within each of the sections that serve discrete functions.