# noteFromFF

0th

Percentile

##### Deriving notes from frequencies

Deriving notes from given (fundamental) frequencies.

Keywords
utilities
##### Usage
noteFromFF(x, diapason = 440, roundshift = 0)
##### Arguments
x

Fundamental frequency.

diapason

Frequency of diapason a, default is 440 (Hertz).

roundshift

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 roundshift is 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.

Example: if x = 452 and diapason = 440, the internally calculated real value of 0.46583 is rounded to 0, but for roundshift = 0.1 we get 0.56583 and it is rounded to note 1.

##### Details

The formula used is simply round(12 * log(x / diapason, 2) + roundshift).

##### Value

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 diapason. For example: 0 indicates diapason a, 3: c', 12: a', …

FF, periodogram, and tuneR for a very complete example.