Double Flat Sign A double flat sign (bb) further flattens a note which is already flat .
Flat Sign A flat sign (b) lowers or 'flattens' a note. It affects all notes in the same position which follow in the bar. Written immediately after the clef, it is part of the key signature.
Natural Flat Sign A natural flat sign contradicts (naturalises) a double flat sign (bb).
Accidental any sharp, flat, or natural that is not given in the key signature. An accidental in front of a note applies as often as the note is repeated at that particular octave during the remainder of the bar it is in. In the bar that comes after accidental sharps or flats is usual to find 'warning' to contradict the accidentals in the previous bar.
Key Signatures A grouping of sharp or flat signs placed immediately after the clef on the lines of the staff. Unless contradicted (cancelled) by natural signs, they affect every note with the same name as the ones marked.
Natural Sign This contradicts (naturalizes) a sharp (#) or flat (b) -- the note marked becomes a 'natural' note. If affects all notes in the same position which follow in the bar .
