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// Functions for converting frequencies to the closest musical note. These
// are tuned to use A4 (MIDI note 69 LOL) as exactly 440 Hz.
// Sample usage:
// note[440 Hz]
note[f is frequency] :=
{
noteNames = ["C", "C♯/D♭", "D", "D♯/E♭", "E", "F", "F♯/G♭", "G", "G♯/A♭", "A", "A♯/B♭", "B"]
roundnotes = MIDINote[f]
octaves = floor[roundnotes/12] - 1 // Octaves above C0 (MIDI 0 is at C-1)
scale = roundnotes - ((octaves+1) * 12) // Semitones above C in that octave
return noteNames@scale + octaves
}
/** Turns a frequency into the closest MIDI note number. Also note that this
is extrapolated, so there can be notes smaller than 0 or greater than 127.
MIDI starts with note 0 being C-1 at about 8.1758 Hz and goes up to
note 127 being G9 at ~12544 Hz.
A4 is note 69 at exactly 440 Hz.
C4 "middle C" is note 60
Sample usage:
MIDINote[440 Hz]
*/
MIDINote[f is frequency] :=
{
notesize = 2^(1/12)
A4 = 440 Hz
C4 = A4 / (notesize^9) // Freq. of C4 ("Middle C"), 9 semitones down from A4
CMinus1 = C4 / 2^5 // C-1 is MIDI note 0, 5 octaves down from C4
ratio = f / CMinus1
notes = ln[ratio] / ln[notesize] // This is number of semitones above C-1
roundnotes = round[notes]
return roundnotes
}
Download or view note.frink in plain text format
This is a program written in the programming language Frink.
For more information, view the Frink
Documentation or see More Sample Frink Programs.
Alan Eliasen was born 20217 days, 18 hours, 10 minutes ago.