When we differentiate between foreground, middleground, and background parts in vocal music, the shorthand tends to be about dynamics – volume. Louder for the foreground, quieter for the background.
But there is more to differentiating these parts than just pure decibel change.
- Volume change. Naturally.
- Timbre change. Brighter, more core for foreground. Lighter, less core for background.
- Microphone adjustment. Obviously this doesn’t work for traditional un-miked choral ensembles, but if you are singing on microphones, even an inch of adjustment can thin out and dampen your sound.
- Placement on stage. You can map the foreground and background parts physically onstage, with foreground parts being closer to the audience.
- Physicality change. The activity of your body communicates a lot about your relative importance to most audience members. You can tell the audience to listen to you with your body, or you can guide them to listen to something else.
Of course, all this is predicated on each ensemble member understanding the structure of the music well enough to recognize how the part their singing fits into the whole.