guitar scale
C Mixolydian
C1D2E3F4G5A6B♭♭7
Major with a flattened seventh: the scale that fits a dominant seventh chord without altering it.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
CWDWEHFWGWAHB♭WC
What is true of it
C Mixolydian is C, D, E, F, G, A and B♭, and back to C.
Its steps are W – W – H – W – W – H – W, where W is a whole step and H a half.
On the same tonic, C major differs from it by exactly one note.
Across the first twelve frets of the guitar its notes fall in 47 places, which is what makes a scale a shape rather than a list.
Chords made only of these notes
CmajorC7dominant seventhDmminorDm7minor seventhEdimdiminishedEm7♭5half-diminished seventhFmajorFmaj7major seventh
Found by testing every chord in the catalogue against these 7 sounds, not chosen.