ty (the integration in FM
changes the effective initial phase).
By varying the relative phases, we can get a changing spectrum from these cancellations.  Here is a 
CLM instrument that shows this (subtle) effect:
</p>

<!-- CLM CASE 
<pre class="indented">
(definstrument fm (beg end freq amp mc-ratio index car-phase mod-phase skew-func skew)
  (let ((cr (make-oscil freq car-phase))
        (md (make-oscil (* freq mc-ratio) mod-phase))
        (skewf (make-env skew-func :scaler (hz-&gt;radians (* skew mc-rat