Function freq

Basic audio analyser. Returns FFT analysis. Use peakLevel if you want the sound level, or basic if you also want the waveform.

const onData = (freq, analyser) => {
 // Demo: Print out each sound frequency (Hz) and amount of energy in that band
 for (let i=0;i<freq.length;i++) {
   const f = analyser.getFrequencyAtIndex(0);
   console.log(`${i}. frequency: ${f} amount: ${freq[i]}`);
 }
}
freq(onData, {fftSize:512});
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Note: Browers won't allow microphone access unless the call has come from a user-interaction, eg pointerup event handler.