wavtools
Version:
Record and stream WAV audio data in the browser across all platforms
61 lines (56 loc) • 1.46 kB
JavaScript
/**
* Constants for help with visualization
* Helps map frequency ranges from Fast Fourier Transform
* to human-interpretable ranges, notably music ranges and
* human vocal ranges.
*/
// Eighth octave frequencies
const octave8Frequencies = [
4186.01, 4434.92, 4698.63, 4978.03, 5274.04, 5587.65, 5919.91, 6271.93,
6644.88, 7040.0, 7458.62, 7902.13,
];
// Labels for each of the above frequencies
const octave8FrequencyLabels = [
'C',
'C#',
'D',
'D#',
'E',
'F',
'F#',
'G',
'G#',
'A',
'A#',
'B',
];
/**
* All note frequencies from 1st to 8th octave
* in format "A#8" (A#, 8th octave)
*/
export const noteFrequencies = [];
export const noteFrequencyLabels = [];
for (let i = 1; i <= 8; i++) {
for (let f = 0; f < octave8Frequencies.length; f++) {
const freq = octave8Frequencies[f];
noteFrequencies.push(freq / Math.pow(2, 8 - i));
noteFrequencyLabels.push(octave8FrequencyLabels[f] + i);
}
}
/**
* Subset of the note frequencies between 32 and 2000 Hz
* 6 octave range: C1 to B6
*/
const voiceFrequencyRange = [32.0, 2000.0];
export const voiceFrequencies = noteFrequencies.filter((_, i) => {
return (
noteFrequencies[i] > voiceFrequencyRange[0] &&
noteFrequencies[i] < voiceFrequencyRange[1]
);
});
export const voiceFrequencyLabels = noteFrequencyLabels.filter((_, i) => {
return (
noteFrequencies[i] > voiceFrequencyRange[0] &&
noteFrequencies[i] < voiceFrequencyRange[1]
);
});