freq


tonal-freq is a collection of functions to perform calculations related to frequencies.

This is part of tonal music theory library.

Usage

``js
var freq = require('tonal-freq')
freq.toFreq('A4') // => 440
freq.note(440) // => 'A4'
freq.noteAndDetune(320) // => ['C4', 200]
`

Install

![npm install tonal-freq](https://npmjs.org/package/tonal-freq/)

API Documentation


* freq
* .eqTempFreq(ref, maxDecimals, note) ⇒ Number
* .toFreq(note) ⇒ Float
* .eqTempFreqToMidi(tuning, freq) ⇒ Number
* .toMidi(freq) ⇒ Number
* .note(freq, useSharps) ⇒ String
* .cents(base, freq) ⇒ Integer

freq.eqTempFreq(ref, maxDecimals, note) ⇒ Number

Return the equal tempered frequency of a note.

This function can be partially applied if note parameter is not present.

Kind: static method of freq
Returns: Number - the frequency

| Param | Type | Description |
| --- | --- | --- |
| ref | Float | the tuning reference |
| maxDecimals | Integer | (Optional) the maximum number of decimals (all by default) |
| note | String \| Pitch | the note to get the frequency from |

Example
`js
eqTempFreq(444, 4, 'C3')
const toFreq = eqTempFreq(444, 2)
toFreq('A3') // => 222
`


freq.toFreq(note) ⇒ Float

Get the frequency of note with 2 decimals precission using A4 440Hz tuning

This is an alias for: eqTempFreq(440, 2, )

Kind: static method of freq
Returns: Float - the frequency in herzs

| Param | Type | Description |
| --- | --- | --- |
| note | Number \| String | the note name or midi number |

Example
`js
freq.toFreq('A4') // => 440
freq.toFreq('C4') // => 261.63
`


freq.eqTempFreqToMidi(tuning, freq) ⇒ Number

Get the midi note from a frequency in equal temperament scale. You can
specify the number of decimals of the midi number.

Kind: static method of freq
Returns: Number - the midi number

| Param | Type | Description |
| --- | --- | --- |
| tuning | Float | (Optional) the reference A4 tuning (440Hz by default) |
| freq | Number | the frequency |

freq.toMidi(freq) ⇒ Number

Get midi number from frequency with two decimals of precission.

This is an alisas for: eqTempFreqToMidi(440, 2, )

Kind: static method of freq
Returns: Number - midi number

| Param | Type |
| --- | --- |
| freq | Float |

Example
`js
freq.toMidi(361) // => 59.96
`


freq.note(freq, useSharps) ⇒ String

Get note name from frequency using an equal temperament scale with 440Hz
as reference

Kind: static method of freq
Returns: String - note name

| Param | Type | Description |
| --- | --- | --- |
| freq | Float | |
| useSharps | Boolean | (Optional) set to true to use sharps instead of flats |

Example
`js
freq.note(440) // => 'A4'
`


freq.cents(base, freq) ⇒ Integer

Get difference in cents between two frequencies. The frequencies can be
expressed with hertzs or midi numbers or note names

Kind: static method of freq
Returns: Integer - The difference in cents

| Param | Type |
| --- | --- |
| base | Float \| Integer \| String |
| freq | Float \| Integer \| String |

Example
`js
import { cents } from 'tonal-freq'
cents('C4', 261) // => -4
``