The forte section here is really bass heavy. Take a look at who plays the opening arpeggio: Basses, cellos, violas, trumpets, horns and bassoons in bar 1 and 2. Only basses, cellos, violas, trumpets and bassoons in bar 3 and 4. This is a very subtle way of shifting the weight from the heavy bass line and up.
The horns in bar 3 and 4 contribute with oboes, violins and timpani to the chordal structure that supports the melody instead.
Talking about chordal structure, see all those D’s in bar 1 timpani and violins? Look at how the oboes are enclosed in that. If you can’t do these reductions in your head, try writing them out on paper.
See then how horns and oboes fit in with the triple stops of the violins. Also remember to Google-search ‘violin positions’. Even though these triple stops are not fit for open strings they naturally fit fourth position.
The first 4 bars also have a little ABA form within the orchestration. The three beats of rest in bar 2 and 3 leaves the violins alone and in itself creates a strong diminuendo. This along with the break off from the strong bass line in bar 3 and 4 gives these bars a very dynamic and orchestrational range.
With these words I end it for today. When you dig deep (and you can go deeper than that) it’s amazing how much you can learn from just 4 bars. But don’t worry: due to the nature of this work, these 4 bars are actually 15% of the Menuetto!
- Wolfgang Amadeus Mozart on Grooveshark (grooveshark.com)