Double flat
A double flat lowers the written pitch by two semitones, or one whole tone. Its apparently enharmonic substitute may sound the same in equal temperament but has a different theoretical spelling.
- Accidentals
- Just before the note
- A curve or arc, A straight line
Do not confuse it with
A single flat lowers one semitone; the double-flat sign lowers two.
What the sources say
- Half Steps, Whole Steps, and Accidentals
A double flat ... lowers a note by two half steps (i.e., a whole step).
- Music Fundamentals
Single accidentals raise or lower the pitch of a note by a half step.
- SMuFL — Standard accidentals (12-EDO)
accidentalDoubleFlat — Double flat