The Classical symphony and string quartet revolutionized instrumental music in the 18th century. These genres showcased the era's focus on structure, thematic development, and emotional expression through multi-movement works for orchestra and chamber ensembles.

Composers like Haydn, Mozart, and Beethoven elevated these forms to new heights. They expanded orchestral instrumentation, explored innovative harmonies, and created intricate thematic relationships, setting the stage for Romantic-era innovations in symphonic and chamber music.

Symphonic Form and Structure

Symphony Structure and Movements

• Symphony is a multi-movement work for orchestra that emerged as the most prestigious instrumental genre of the Classical period
• Typically consists of four movements, each with a distinct tempo, character, and form
  1. First movement: Allegro (fast) in sonata form
  2. Second movement: Slow movement, often in sonata form, theme and variations, or ternary (ABA) form
  3. Third movement: Minuet and trio or scherzo in ternary form
  4. Fourth movement: Allegro or presto (very fast) in sonata or rondo form
• Minuet and trio is a dance-based movement in triple meter with a contrasting middle section (trio) and a return to the minuet (ABA form)
• Scherzo, meaning "joke" in Italian, is a fast-paced movement that often replaces the minuet and trio in the 19th century, maintaining the ternary form

Thematic and Harmonic Development

• Thematic unity is achieved through the use of recurring motifs, themes, or rhythmic patterns throughout the symphony, creating a sense of coherence
• Composers often develop and transform themes through techniques such as fragmentation, inversion, augmentation, and diminution
• Harmonic progression plays a crucial role in shaping the emotional arc of the symphony
  • Modulations to closely related keys (dominant, subdominant, relative major/minor) create a sense of departure and return
  • Chromatic harmonies and distant key relationships heighten tension and drama, especially in development sections

Instrumentation and Genres

String Quartet and Chamber Music

• String quartet emerges as a prominent genre of chamber music, featuring two violins, viola, and cello
• Composers such as Haydn, Mozart, and Beethoven elevate the string quartet to a sophisticated and expressive medium
  • Haydn's Op. 33 quartets, known as the "Russian" quartets, showcase his mastery of the genre
  • Mozart's "Haydn" quartets (K. 387, 421, 428, 458, 464, 465) pay homage to Haydn's innovations
• Chamber music, intended for small ensembles and intimate settings, allows for greater interplay and dialogue between instruments
  • Other chamber genres include the piano trio (violin, cello, piano), string quintet, and serenade

Orchestration in the Classical Period

• The Classical orchestra expands in size and variety of instruments compared to the Baroque period
  • Strings remain the core of the orchestra, with violins divided into first and second sections
  • Woodwinds, including flutes, oboes, clarinets (added later), and bassoons, provide melodic and harmonic support
  • Brass section includes horns and trumpets, with trombones added for special effects
  • Timpani (kettledrums) are the primary percussion instruments
• Composers explore the timbral possibilities and combinations of instruments to create diverse textures and effects
  • Haydn's Symphony No. 103 "Drumroll" features a prominent timpani solo in the slow introduction
  • Mozart's Symphony No. 41 "Jupiter" showcases intricate counterpoint and rich orchestral colors in the finale