DEBUSSY, in the Prelude to the Afternoon of a Faun.
Let's just focus on the beginning.
To begin with, it is a small orchestration, but rare: there are two oboes + an English horn, two harps...
The symphonic poem is based on a melody first exposed by the flute, then re-exposed several times in which it is reharmonized.
Debussy's great achievement here, or one of them, is how to make a flute alone, in its low register (which is very weak) and also on piano, to be heard and stand out among the rest of the orchestra...
Let's hear it,
First we hear the flute alone and at the end of the phrase a transition with the harp and winds.
At the rehearsal position marked 1, at approximately 1:03.... is the first harmonization and that is what we are going to refer to.
How does Debussy make the flute sound so clear, even though the rest of the orchestra is in pp?
There are several things that contribute to this:
1. The dynamics in pp.
2. The tremolando of the strings, which weakens the sound.
3. The tremolando in sul tasto (sur la touche), which makes the sound less bright.
4. Assigning for the bass only two double basses.
5. But the most important thing is the non-interference of the space, of the register.
This scheme summarizes everything: the lowest note of the flute is a G natural, and the highest note of the rest of the orchestra is an F# (clarinets and tremolo violins). This way, even though the flute is in a low and weak register, it has all its space to sound on its own.
Wonderful.