musicdsp.org source code archive - WSInf

end;
// converts from MIDI note to pitch class notation
// the integer part of the number is the octave number, where
// 8 is the octave starting with middle C. The
fractional part
// is the note within the octave, where a 0.01 increment is a
// semitone.
// example: NoteToPch(57)=7.09
function NoteToPch(i:integer):double;
begin
result:=3+(i div 12)+(i mod 12)*0.01;
end;
from : kaleja@estarcion.com
comment : I thought most sources gave A-440Hz = MIDI note 69. MIDI 60 = middle C = ~262Hz, A-440 = "A above middle C". Not so?
from : DFL
comment : Kaleja is correct. Here is some C code:
double MIDItoFreq( char keynum ) {
return 440.0 * pow( 2.0, ((double)keynum - 69.0) / 12.0 );
}
you can double-check the table here:
http://tomscarff.tripod.com/midi_analyser/midi_note_frequency.htm