There are 12 keys. Does it matter which one you pick? As musicians, we’re taught early and often that we should be proficient in all keys and while that’s true, all keys aren’t the same.
Just ask a vocalist. As with vocalists, instruments, and even songs speak differently in different keys. I’m not really talking about people’s perceptions of certain keys being bright or sad.
I think it’s more nuanced than that. What I’m talking about has more to do with a balance between richness and clarity. As any note or song is transposed down, there’s a tipping point in which the harmonics of the notes begin to crowd each other.
We can demonstrate this by constructing a chord built out of sine waves and moving it up and down until we find the maximum amount of richness versus clarity and note independence. In this example, that seems to land somewhere around the key of C. The F above, too crisp.
The F below, unusable. And we can’t always just transpose. We need to restructure the chords.
When the structures around our songs and our instruments are fixed, Choosing a key for them is no different than picking a key for a vocalist.
