getFrequencyOfNote = function (note) {
        var notes = ['A', 'A#', 'B', 'C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#'],
            key_number,
            octave;

        if (note.length === 3) {
            octave = note.charAt(2);
        } else {
            octave = note.charAt(1);
        }

        key_number = notes.indexOf(note.slice(0, -1));

        if (key_number < 3) {
            key_number = key_number + 12 + ((octave - 1) * 12) + 1;
        } else {
            key_number = key_number + ((octave - 1) * 12) + 1;
        }

        return 440 * Math.pow(2, (key_number - 49) / 12);
    }
Get frequency of a given note.
@param  {string} note Musical note to convert into hertz.
@return {number} Frequency of note in hertz.