ke-oscil (* freq mc-ratio)))
	 (skewf (make-env (list 0.0 0.0 1.0 pi) :duration dur)))
    (do ((i start (+ i 1)))
        ((= i end))
      (outa i (* amp (oscil cr 0.0 (* index (oscil md 0.0 (env skewf)))))))))

(with-sound () (fm 0 2 100 0.5 1.0 30.0))
</pre>

<p>The next question is "if we can get cancellations, can we fiddle with the phases and get 
asymmetric FM spectra?".  There are several approaches; an obvious one uses the
fact that:
</p>


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