Work on Shadow on the Sun has me doing a lot more timbral morphing than is my custom. I tend to gravitate towards monochromatic ensembles, or ensembles that have a narrow timbral range—which is one of the reasons I love writing for string quartet so much — so I can focus the ear on other aspects of musical discourse. But the aural image I was going for – a corona that is hotter than the surface from which it emanates – called for a more coloristic approach.
The wind ensemble offers a wonderful pallette for kinds of sounds I was seeking. Because all the instruments (save percussion and harp) are dependent on the human breath, I could easily glide through disparate sound worlds within a shared sonic envelope. I’ve found that the pieces I’ve written that make use of a wide timbral range benefit from having other musical parameters considerably narrowed, so the connection to breathing was important to me.
I also narrowed the harmonic pallette considerably. Entire passages consist of nothing more than permutations of a single chord. For example, I have a passage of sustained saxophones with burbling oboes and bassoons that gradually morphs into muted trumpets and flutes. The shift in timbre is simultaneous with a shift in harmony, but the first harmony is a c minor-major 43, while the second harmony is an eb minor-major 65. The next timbral shift takes us to a g minor-major 42.
In other words, the quality of the chord remains constant throughout, with different roots, inversions and spacings. That harmonic consistency allows me to range through a variety of colors without falling into randomness.
More on this in another post.