Deriving notes from frequencies
Deriving notes from given (fundamental) frequencies.
noteFromFF(x, diapason = 440, roundshift = 0)
Frequency of diapason a, default is 440 (Hertz).
Shift that indicates from here to round to the next integer (note). The default (0) is “classical” rounding as described in
round. A higher value means that
roundshiftis added to the calculated real note value before rounding to an integer. This is useful if it is unclear that some instruments really shift the note in the center between two theoretical frequencies.
x = 452and
diapason = 440, the internally calculated real value of 0.46583 is rounded to 0, but for
roundshift = 0.1we get 0.56583 and it is rounded to note 1.
The formula used is simply
round(12 * log(x / diapason, 2) + roundshift).
An integer representing the (rounded) difference in halftones from diapason a,
i.e. indicating the note that corresponds to fundamental frequency
x given the value of
For example: 0 indicates diapason a, 3: c', 12: a', …