mples dur)))
	 (cr (make-oscil freq carrier-phase))
         (n (length mc-ratios))
         (modulators (make-vector n))
         (fm-indices (make-float-vector n)))
    (do ((i 0 (+ i 1)))
	((= i n))
      (set! (modulators i) (make-oscil (* freq (mc-ratios i)) (mod-phases i)))
      (set! (fm-indices i) (hz-&gt;radians (* freq (indexes i) (mc-ratios i)))))
    (do ((i start (+ i 1)))
        ((= i end))
      (let ((sum 0.0))
        (do ((k 0 (+ k 1)))
	    ((= k n))
	  (set! sum (+ sum (* (fm-indices k