Query: What did Beethoven expand in his Symphonies, 3, 5, 6 and 9?
Context: The composer's instrumentation usually included paired flutes, oboes, clarinets, bassoons, horns and trumpets. Beethoven carefully calculated the expansion of this particular timbral "palette" in Symphonies 3, 5, 6, and 9 for an innovative effect. The third horn in the "Eroica" Symphony arrives to provide not only some harmonic flexibility, but also the effect of "choral" brass in the Trio.