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).;
Musical note number (and 69 is the number of semitones between C (note 0) and A). And in the opposite direction, to obtain the frequency from a MIDI note "p", the formula is defined as: For notes in an A440 equal temperament, this formula delivers the standard MIDI note number ("p"). Any other frequencies fill the space between the whole numbers evenly. This lets MIDI instruments be tuned accurately in any microtuning scale, including non-western traditional tunings. Music notation systems have used letters of the alphabet for centuries. The 6th-century philosopher Boethius is known to have used the first fourteen letters of