     /* Input ADC value */
     value = ADC;
 
+    /* Subtract zero-offset */
+    value -= fft_zeroPoint;
+
     /* Add random noise */
     if (RANDOM_NOISE) {
       value += random(-RANDOM_NOISE, RANDOM_NOISE);

    x += FD_GRAPH_SIZE + 1;
  }

  // Convert the sum of all waveform captures into a graph intensity range
  intensity = map(captureSum,-10000,10000,TD_GRAPH_Y,TD_GRAPH_Y+TD_GRAPH_H);
  intensity = constrain(intensity, TD_GRAPH_Y, TD_GRAPH_Y+TD_GRAPH_H);

  //ADCSRA = _BV(ADSC) | _BV(ADEN) | _BV(ADATE) | _BV(ADIE) | _BV(ADPS2) | _BV(ADPS1); //prescaler 64 : 19231 Hz - 300Hz per 64 divisions
  ADCSRA = _BV(ADSC) | _BV(ADEN) | _BV(ADATE) | _BV(ADIE) | _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0); // prescaler 128 : 9615 Hz - 150 Hz per 64 divisions, better for most music
  sei();
}