Image by Roman Averin

Finding Chords in Charlie’s Tree

A simple method to find any chord from it’s root.

This week on my journey from novice to composer, my music teacher Charlie introduced me to the theory of harmony. I’m also working through Jason Allen’s comprehensive music theory class on Skillshare (excellent and highly recommended) and both have aligned on discussing chords, albeit from two approaches.

Jason looks at building chords via musical notation based on the notes within a scale. This has lead to an understanding of how the chords relate to the scale. Jason also teaches the different chords in a key and their Roman numerals. In particular remembering the pattern of Major (I), minor (ii), minor (iii), Major (IV), Major (V), minor (vi), diminished (vii). For example, in any key of C we have C, Dm, Em, F, G, Am, Bdim.

These various chords are made up of notes that harmonise with one other and the interval (tones between them) are made up of major 3rds (4 semi or half-tones) and minor 3rds (3 semi/half tones).

Tree of thirds

To help find all these chords Charlie showed me a nice way of visually building each chord from it’s root note using a tree of thirds.

Charlie’s Tree of Thirds

In the tree above, we can see that starting with the root note (in this case D) we can take different paths when stepping up chromatically from the root note. So the major 3rd from D is F#, and the major 3rd from F# is A#. If we play these three notes together we get a D augmented chord. From here we can add another major 3rd but that lands us back on D so we still have a D augmented (+) chord. However is we step up a minor 3rd from A# we get C# which gives is a D+7 chord by playing D, F#, A# and C# together.

Maybe my scientific background takes to Charlies visualisation of the chords this way butI certainly find it a clear way to understand how each of the chords are made up. You can take this even further and start working out how the various individual chords relate to each other which leads to ambiguous combinations that could be two different chords.

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