# noteFromFF: Deriving notes from frequencies In tuneR: Analysis of Music and Speech

## Description

Deriving notes from given (fundamental) frequencies.

## Usage

 `1` ```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', ...

## Author(s)

Uwe Ligges [email protected]

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