Frequency calculator

This is a small library to convert frequencies to steps, notes and octaves.

To use this library, get the files with NPM or bower:

npm install frequency-calculator

or

bower install frequency-calculator

Once installed you can import the the library:

import FrequencyCalculator from 'frequency-calculator';

calculateSteps

You can calculate the number of half steps between the base note (A4) and a given note:

FrequencyCalculator.calculateSteps('G', 4) // -> -2;

calculateFrequencyByNote

Once imported you can calculate the frequency of a note by supplying the note name and octave:

FrequencyCalculator.calculateFrequencyByNote('C', 0) // -> 16.35Hz;

calculateFrequencyByStep

If you know the number of half steps, you can also calculate the frequency based on these steps, this can be a negative number if the note is below the base note (A4):

FrequencyCalculator.calculateFrequencyByStep(-12) // -> 220.00Hz;

calculateStepsFromFrequency

You calculate the amount of half steps between a frequency and A4 (440Hz). If you want to round the steps, you can add true as the second parameter:

FrequencyCalculator.calculateStepsFromFrequency(415.30) // -> -1.0001958238467235;

or

FrequencyCalculator.calculateStepsFromFrequency(415.30, true) // -> -1;

calculateNoteBySteps

You can calculate a note based on the the distance in half steps of A4:

FrequencyCalculator.calculateNoteBySteps(-12) // -> A;

calculateOctaveBySteps

You can calculate an octave based on the the distance in half steps of A4, if you don't want the octave to be relative to A4, add false as the second parameter:

FrequencyCalculator.calculateOctaveBySteps(-12); // -> -1

or

FrequencyCalculator.calculateOctaveBySteps(-12, false); // -> -3

calculateNoteByFrequency

You can calculate the note of a frequency:

FrequencyCalculator.calculateNoteByFrequency(440); // -> A

calculateOctaveByFrequency

You can calculate the octave of a frequency. If you don't want the octave to be relative to A4, add false as the second parameter:

FrequencyCalculator.calculateOctaveByFrequency(440); // -> 0

or

FrequencyCalculator.calculateOctaveByFrequency(440, false); // -> 4

TODO

• [ ] Write tests
• [ ] Create a demo

The MIT License (MIT)

Copyright © 2016 Sam Bellen

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.