       (outa i (* vol (oscil fm-carrier (* .0001 ex)))) ; sampled ex...
         (outb i (* vol (oscil pm-carrier 0.0 ex)))
         (outc i ex)
         (outd i sumex)
         (set! sumex (+ sumex (* .0001 ex)))))))

(with-sound (:clipped #f :statistics #t :channels 4) (fmpmex 0 1 1000 .5))


;; FM(white)=PM(brown):
(define* (fmpmran beg dur freq amp (index 1.0))
  (let* ((start (seconds->samples beg))
         (end (+ start (seconds->samples dur)))
	 (fm-carrier (make-oscil freq))
	 (pm-carrier (make-osc