note-frequency-map

A npm package for music note frequency lookup

Alpha

This package is currently in alpha, bugs and big structure changes may occur!

If you find a bug, or miss a feature, open an issue on the GitHub page!

Installation

Using npm:

$ npm install note-frequency-map

In NodeJS:

// Load the package
const FrequencyMap = require('note-frequency-map');

Examples

Find the frequency of a note:

const FrequencyMap = require('note-frequency-map');
let myNote = FrequencyMap.noteFromName('A3');
console.log(myNote.frequency); // > 220

---

Find the note from a frequency

const FrequencyMap = require('note-frequency-map');
let myNote = FrequencyMap.noteFromFreq(880);
console.log(myNote.note); // > 'A5'

---

Change the root: The root note is A4=440 by default

const FrequencyMap = require('note-frequency-map');
FrequencyMap.setRoot('A4', 442); // A4 is normally the refrence note, but any note works!
let myNote = FrequencyMap.noteFromName('A3');
console.log(myNote.frequency); // > 221

---

Compare two note objects

const FrequencyMap = require('note-frequency-map');
let myFirstNote = FrequencyMap.noteFromName('Bb6');
let mySecondNote = FrequencyMap.noteFromName('C#3');
let comparasonObject = myFirstNote.compare(mySecondNote);
console.log(comparasonObject.summary);
// > 'The note A#6 is 2 octaves and 9 semitones away from C#3'

Functionality

The note-frequency-map object has three methods

• .noteFromName(name) - creat a Note object from the note name (e.g. 'C#3')
• .noteFromFreq(frequency) - create a Note object from a frequency (e.g. 880)
• .setRoot(name, frequency) - set the root note + frequency

---

The Note object has two methods and 7 properties

• .transpose(semitones) - transpose to another note
• .compare(otherNoteObject) - see how two notes compare
• .name - the name of the note (e.g. 'Bb')
• .octave - the octave of the note (e.g. 5)
• .note - the name + the octave (e.g. 'Bb5')
• .frequency - the frequency of the note
• .tuning - what root note it was tuned to, an object
• .centsOff - how much out of tune the note is, usefull when finding note from frequency
• .err - is defined of something went wrong

Protip

console.log() the data while experimenting. This way you will easely see how things is structured

Changelog

Changelog for version 0.0.7

• Optimized the note finder (from frequency) alogrithm
• note-frequency-map.noteFromName(name) now support both b and ♭ as flat symbols
• Fixed console.log() typo in README.md
• Bug fixes
• Code cleanup

Check the GitHub page for more details