Harmonic Charge and Form

I mentioned in my post about last week's Arrangers’ Workshop that we’d talked about the relationship between the circle of fifths and the sense of a song’s form, and that it probably needed a post in its own right to cover. So, here is that post.

I’ve written before about Harmonic Charge as a measure of the inherent energy a chord has within the context of a particular key. Here, we’re just talking about dimension of harmonic charge that involves the potential energy of distance round the circle of fifths. The other dimensions (major/minor and presence/absence of a tritone) seem to me more about flavour than structure – important considerations for a song’s expressive feel, but perhaps secondary when thinking about mapping out its shape.

So, the point about the circle of fifths is that it is measure of tonal distance. Chord III is further away from ‘home’ than chord V (as it is V of VI, which is V of II, which is V of V, and then you’re nearly home). So, chords further out round the circle inherently feel more active, as you’re going to have travel further harmonically to get back home to where the music feels at rest.

Hence, when you’re planning the primary harmonies of your arrangement, you can be strategic about where you place the more active chords within the form so as to create a coherent pattern of tension and release. You want the journey the harmony takes you on works in tandem with the journey traced by melody and lyric.

So, to a concrete example to illustrate. The following graph maps the harmonic choices of one of the arrangements of the set piece we workshopped that day.

You’ll see that mostly it’s working in units of two bars per chord, and for each of the first two (parallel) phrases takes us on a gentle eight-bar journey out to II and home again. The bridge gives a contrasting melody, and starts off hanging around nearer home, before setting off for II again to finish on an imperfect cadence, ready for the reprise. This starts off with two bars of I as we have come to expect, then suddenly dives off right out to III before romping home at the rate of one chord per bar.

Now, the effect of this in performance was very surprising. And the reasons why it was surprising were twofold. One was the sudden acceleration of harmonic rhythm from two bars per chord to one. The other was the introduction of such striking harmonic move so late in the game. Mapping it out as a graph makes both the suddenness of the move and the acceleration of the rate of harmonic change visually obvious.

By contrast, here is a graph of another of our examples:

Here, the big striking move occurs at the start of the bridge, where we get the new melodic material. This creates a central focal point for the arrangement to build up towards and move away from. After this strong harmonic journey in bridge, the decision to come home via chord IV at the end counter-balances the activity with a sense of rest. However, I felt that using that same move in the second phrase lost some sense of energy or momentum, following the rather perky use of chord VI right at the start. And the graph looks a bit like a marquee that’s missing a tent-pole – the music rather sags just there.

For a more balanced form, I’d suggest either switching over the harmonisations of the first two phrases to move from relaxation, through some activity to greater activity and back to relaxation:

Or using the first phrase’s harmony for each of the first two phrases:

(On reflection, I think I prefer the second of these two options. There’s a good precedent from people like Bach and Schumann using the subdominant to reassure us that we’ve got back home at the end of a harmonic adventure. But using it earlier feels a bit like getting comfy in your slippers before you’ve been out to do anything.)

Mapping form in terms of tonal structure gives a more dynamic idea of musical shape than the traditional kinds of formal analysis that break things into sections according to patterns of repetition and contrast. And actually, it’s the relationship between the two that matters for the emotional experience of the listener.