Homework 6

Tube Model

Sound
Spectrum Image

String

Sound
Spectrum Image

Code

(define echo  ; IIR version, aka feed-back or recursive delay
  (lambda* (secs #&optional (att 1.0))
    (let ((long-delay (make-delay (round (* secs (srate)))))
	  (prev-echo (make-delay 1))
	  (echo_old 0)
	  (echo_new 0)
	  (a 0.707)
	  (input_scale 0.5)
	  (yz 0.0)                                       
	  (y0 0.0)
	  (from_delay 0))
      (lambda (x0)
	(set! echo_old (tap prev-echo))
	(set! from_delay (tap long-delay))                      
	(set! echo_new (+ (* input_scale x0) (* att from_delay)))
	(set! y0 (* a (+ echo_old echo_new)))
	(delay long-delay y0)
	(delay prev-echo echo_new)
	y0)
      )))



;-------------------------------------
;Make a tube-like sound
(click 0.3)
(map-chan (echo .0025495 .4)) 

;-------------------------------------
;Make a string-like sound
(click 2)
(map-chan (echo 0.0025495 0.707))