C 7#9 Chord on Octave Mandolin
How to play the C 7#9 chord on Octave Mandolin: fretboard diagrams, finger positions, the notes that build it, and alternate voicings up the neck.
The C 7#9 chord is an extended or altered dominant that stacks ninths, elevenths, thirteenths, or chromatic tensions over a dominant-seventh core. It is built from the notes C, D#, E, G, A#. This page shows how to play C 7#9 on Octave Mandolin with clear fretboard diagrams and suggested finger positions.
The shape nearest the nut leaves the E string open and takes the rest at fret 1, reaching across 5 frets. C falls on the G string. It sounds from C3 up to E4.
Octave Mandolin is strung in four courses of two, so each stopped note here sounds as two — which is why the shape rings thicker than the same grip on a single-strung instrument.
Browse alternate voicings to find the one that sits best under your fingers, then compare it with the other chord types built on C or explore the same shape in nearby keys. The diagrams list the notes in each voicing so you can connect the shape to the theory behind it.