langSynth.</p>
  <h4 id="tremolo"><a href="#tremolo" class="header-anchor"
  aria-hidden="true">Tremolo</a></h4>
  <p>Intention of tremolo is to crudely imitate the distance from
  vibrating object to microphone. Modulation signal is sine wave.</p>
  <dl>
  <dt>Mix</dt>
  <dd>
  <p>Mixing ratio of input and delay output.</p>
  <p>When the value is 0.0, input is bypassed.</p>
  </dd>
  <dt>Depth</dt>
  <dd>
  <p>Modulation amount to the gain of delay output.</p>
  </dd>
  <dt>Delay [s]</dt>
  <dd>
  <p>Maxim