Sixty-fourth note twenty-eighth note—otherwise known as the "semihemidemisemiquaver" —and even shorter notes, are occasionally found. Sixty-fourth note In music notation, a sixty-fourth note (American), or hemidemisemiquaver or semidemisemiquaver (British), sometimes called a half-thirty-second note , is a note played for half the duration of a thirty-second note (or demisemiquaver), hence the name. It first occurs in the late 17th century and, apart from rare occurrences of hundred twenty-eighth notes (semihemidemisemiquavers) and two hundred fifty-sixth notes (demisemihemidemisemiquavers), it is the shortest value found in musical notation . Sixty-fourth notes are notated with a filled-in oval note head and a straight note stem with
Double whole note the "brevis" was to be considered the unit of time ("tactus"), instead of the usual "semibrevis". The old symbol , used as an alternative to the numerical proportion 2:1 in mensural notation, is carried over into modern notational practice to indicate a smaller relative value per note shape. It is normally used for music in a relatively quick tempo, where it indicates two minim (half note) beats in a bar of four crotchets (quarter notes), while is the equivalent of , with four crotchet beats . Double whole note In music, a double whole note (American), breve (international), or double