#
Sharp
Raises the pitch by one semitone (100 cents)
b
Flat
Lowers the pitch by one semitone (100 cents)
bs
Half Flat
Lowers the pitch by a quarter tone (50 cents). Common in Arabic maqams.
+
Half Sharp
Raises the pitch by a quarter tone (50 cents). Common in Arabic maqams.
++
Three Quarter Sharp
Raises the pitch by three quarters of a tone (150 cents). Used in some Arabic maqams.
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Double Sharp
Raises the pitch by two semitones (200 cents)
bb
Double Flat
Lowers the pitch by two semitones (200 cents)