Friday, September 18, 2009

The Circle of Fifths

Sooner or later, the legendary Circle of 5ths must make an appearance. For our purposes, we are highlighting the keys of C and Gb/F#. As we've established in the previous post, Gb is preferable to F# in Fretography theory because it's a flat-5th above C, as opposed to F# which is a sharp-4th. The theoretical difference may seem arbitrary, but there are ramifications of each key which lead in different directions.

Consider that all the keys in the circle containing sharps are based on natural tones, F# would be the only practical exception. The key of C#, which follows F# in the circle has 7 sharps, while its enharmonic Db has 6 flats. As a rule it's preferable to opt for the key with more natural tones, so Db wins out over C#. Also, were we to accept F# over Gb, we would have, by default, seven keys with natural tonics, one key with a sharp tonic and four keys with flat tonics. If we choose Gb we have seven natural tonics and five flat tonics; much more logical since there are seven white keys and five black keys.

That said, treating the black-key tones as sharps in no way undercuts the Fretographic symmetry as we have outlined it. This point is largely a theoretical one. If we chose F# as the key, the Axis would still be Aeolian, but it would be based on D# and not Eb as it is in the key of Gb. In fact Fretography theory would be flawed if it was at odds with the enharmonic relationship between F# and Gb.

This blog is more concerned with mapping the notes on the fretboard than explaining every nuance of music theory, so we'll leave it at that for now. Suffice to say that here we will refer to the axis of black-key tones at the 11th fret as the Secondary Aeolian Axis which is based on its theoretical tonic of Gb on the 3rd string.

Next .... Black-key chords.

All contents of this blog are © Mark Newstetter

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