How to analyse a song harmonically in Harmony Space

If the chord sequence for a song avoids cliché, and it is memorable, durable and interesting, there are likely to be discoverable sources of power behind it.

Teasing out why harmonic sequences work well can reveal ideas, processes and games that can be used to craft new chord sequences that also work well. This is one test that a musical analysis is meaningful.

Simply specifying each chord is not in general very informative..

To investigate more deeply, a good first step is to trace the roots, and then shift around the key windows to find positions where everything (or at least substantial sections) fit. There may be more than one such position, or there may be none.

A good second step is to trace the full chords (not just the roots) for the first few chords and see if there is any combination of keys and modes that allows all or most of the chord qualities to fit in the key window.

The way in which the roots of the chord sequence moves, and the way in which they start and finish are also useful clues. The aeolian, dorian, phrygian and mixolydian modes all have distinctive movement patterns and distinctive ending patterns (cadences).

The result of the above process can be read off as a functional harmonic analysis. If you play something in harmony space respecting best fit in this way, this is all that is needed to let you print a functional analysis in roman or alphabetic notation.

But the aim of the process is not prescriptive, nor to match the harmony to pre-existing patterns. Rather, memorable, durable and interesting pieces of music will typically reflect existing building blocks and patterns but will come up with new twists and combinations. Following these twists and turns can be highly insightful and can help in coming up with new musical ideas.

More advanced considerations

In many genres (including recent popular music) it can be useful to take into account extended modes such as picardian and dominant V inflections of the minor modes (aeolian, minor, dorian and phrygian).

The analysis process described above embodies a heuristic known as the assumption of diatonicity. This can be useful and revealing heuristic. But it’s only a heuristic.

Common sense is also needed, the ear always needs to be used, and there are many other heuristics.. Harmony space can be useful but it should not be used in isolation. If possible, try continually to translate insights however inexpertly onto guitar or keyboard, or other instruments, or sing, or play with other people.