code: def unpitched_low(dur, idx):
    
    env = sinusoid(lag2freq(dur * 2)).limit(dur) ** 2
    freq = 40 + 20 * sinusoid(1000 * Hz, phase=uniform(-pi, pi)) # Hz
    result = (low_table(freq * Hz) + low_table(freq * 1.1 * Hz)) * env * .5
    return list(result)
docs: Non-harmonic bass/lower frequency sound as a list (due to memoization).
  
    Parameters
    ----------
    dur:
      Duration, in samples.
    idx:
      Zero or one (integer), for a small difference to the sound played.
  
    Returns
    -------
    A list with the synthesized note.