I just dove into the Berklee Press book of Jazz Harmony although it’s pretty dense (in good way). The first sentences of Chapter 1 begin:
Mainstream jazz harmony is both tonal and functional:
Tonal music has one pitch as its primary focus: a tonal center that servers as a reference point for all the other chords and melody notes in the piece.
Harmonic function describes the relationship of a chord to its tonal center. Chords function by creating a resolving motion around the tonic.
At the risk of being over analytical, the notion of a tonal center isn’t that well articulated here. Is the tonal center just the key? (in which case, why not just say it’s the key?). But the definition also explains how “all the other chords and melody notes” reference the tonal center. Does that mean the tonal center is a chord? (e.g. C Major and not just C?).
The book does offer an illuminating image of chords and melody notes orbiting this tonal center each with its own gravity which pulls the composition away from and back to the tonal center.
Another analogy employed is that of language:
Scale degrees [e.g. 2nd 3rd 5th] and their tendencies are like the letters of a language - the most basic unit. Next, we will look at the “words” - diatonic chords, the vocabulary of harmony. We will do this through the lens of harmonic function: the essential dynamic role each chord plays. After those basic identities are defined, we will combine them and explore the grammar of harmonic progression.
And you thought music theory was going to be difficult to learn .
There’s a suite of technical terms in this book and I am hoping to lean on this forum for assistance making sense of them. The first question is: Is the “Tonal Center” just the key?"