ase)))
	    (fm-val (* amp (sin carrier-phase))))
	(set! carrier-phase (+ carrier-phase modulation carrier-phase-incr))
	(set! modulator-phase (+ modulator-phase modulator-phase-incr))
	(outb i fm-val)))))

(with-sound (:channels 2) 
  (pm 0 10000 1000 .5 0.25 4)
  (fm 0 10000 1000 .5 0.25 4))

(with-sound (:channels 2) 
  (pm 0 10000 1000 .5 0.5 10)
  (fm 0 10000 1000 .5 0.5 10))
</pre>
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</div>


<!-- a check of these instruments:

(define (channel-distance-max s1 c1 s2 c2)
  (let* ((r1 (make-samp