Musical note standardised at 440 Hz, lying in the octave containing notes from C (middle C) to B. The lowest note on most pianos is A, the highest C. The MIDI system for electronic musical instruments and computers uses a straight count starting with note 0 for C at 8.1758 Hz up to note 127 for G at 12,544 Hz. A written note can also have a note value, a code that determines the note's relative duration. In order of halving duration, they are: double note (breve); whole note (semibreve); half note (minim); quarter note (crotchet); eighth note (quaver); sixteenth note (semiquaver).;
Blue note Blue note In jazz and blues, a blue note is a note that—for expressive purposes—is sung or played at a slightly different pitch than standard. Typically the alteration is between a quartertone and a semitone, but this varies among performers and genres. The existence of the blue note within music derives, in part, from the fact that equal temperament in western diatonic harmony is an artifice or compromise originally employed in the eighteenth century to address problems posed in the creation of keyboard instruments. Equal temperament was an artificial 'straightening out' of a tendency for the natural harmonic series (musical