cy;
          osc.start();
          oscillators[frequency] = osc;
        };

        const muteFrequency = (frequency) => {
          if (oscillators[frequency]) {
            oscillators[frequency].stop();
            oscillators[frequency] = null;
            delete oscillators[frequency];
          }
        };

        (function animateCanvas() {
          let spectrumCanvas = document.querySelector('canvas.spectrum');
          let spectrumCtx = spectrumCanvas.getContext('2d');

          let wavefor