  <dd>
  <p>Decay time of a noise burst.</p>
  <p>When the value of <code>Noise Decay</code> is small, it sounds like
  pulse train. However, the naive pulse train used for noise generator
  is not anti-aliased. Therefore it has different texture to BLIT.</p>
  </dd>
  <dt>Bounce</dt>
  <dd>
  <p>Amount of bouncing effect.</p>
  <p>The bouncing effect is tied to AD envelope output, and bouncing
  interval becomes shorter when AD envelope amplitude becomes lower. The
  effect is disabled when <code>Bounce</c