The b musical notation symbol (approximated), also known as the flat, can appear amid a song (an accidental), or in the key signature. Any note that falls on the note modified by the flat will cause any previous accidental or key signature (for that note) to be considered moot and the new, flatted, value to take its place. The value is then lowered a half-step harmonically.

For example:

  • C becomes Cb (which is enharmonically the same as a B).
  • D# becomes a Db (which is the same as C#)

And so on.