(define *pi* 3.1415926535897)
(define *amp* 28000)
(define *freq* 48000)

(define (noise)
  (with-output-to-file "/dev/audio" (lambda ()
                                      (let loop ((t 1)
                                                 (v 0))
                                        (printf "~a" (+ *amp* (sin (/ (* 2 v *pi*) *freq* t))))
                                        (when (not (char-ready?))
                                          (loop (add1 1) (+ v *freq*)))))))