1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; Jean Claude Risset's rhythm paradox: the increasing beat.
;;; ===================================
;;; Docs:
;;; Risset, J. C. (1991).
;;; Current Directions in Computer Music Research,
;;; chapter Paradoxical Sounds, (pp. 149-158)
;;;
;;; John Pierce, The Science of Musical Sound.
;;;
;;; Snd (guile scheme) code by Juan Reyes
;;; juanig <at> ccrma.Stanford (dot) EDU
;;; (c) MMVII
;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Snd initialize (if needed)
;;;
;;
;; (use-modules (ice-9 optargs))
;;
;; (provide 'snd-clm-ins.scm)
;; (if (not (provided? 'snd-ws.scm)) (load-from-path "ws.scm"))
;; (if (not (provided? 'snd-env.scm)) (load-from-path "env.scm"))
;;; Dependency:
;;;
;;; (load "ws.scm")
;;;
;;;
;;; Overall amplitude gaussian
;;;
(define ampgaussian
(lambda (t m)
(let* ((s m) ;; Max Iterations
(r (/ s 2)) ;; Half Max Iterations
(sigma 4.0)) ;; sigma > 1 convex curve
;;
(exp (* (* (/ -1 2) (* sigma sigma)) (expt (- (/ t r) 1) 2)))
)))
;;; define e
(define e (exp 1))
;;;
;;; Normal curve for increasing / decreasing beat
;;;
(define jcrcurve
(lambda (t m) ;; m = max number of iterations
(let ((k (* (/ -1 m) (log 32))))
(expt e (* k t)))) )
;;;
;;; Simple one OSCIL intrument with a fast attack (percussive) ADSR envelope
;;;
(definstrument (beats start duration freq amp :key
(percu-env '(0 0 8 1 100 0))
)
(let* ((beg (seconds->samples start))
(length (+ beg (seconds->samples duration)))
(signal (make-oscil :frequency freq))
;;;
;;; here we have our envelope
;;;
(percuenv (make-env :envelope percu-env
:scaler amp
:base 32
:duration duration )))
(run
(lambda ()
(do ((i beg (1+ i)))
((= i length))
(begin
(outa i (* (env percuenv) (oscil signal)) *output* ) )
)))))
;;; (with-sound () (beats 0 1.25 1000 0.7))
;;;
;;; Simple case:
;;; ===========
;;; This case is shown on J. Pierce The Science of Musical Sound
;;;
;;; Each of the beats is constructed with a sine frequency of (1000Hz)
;;; the beats are multiplied by a percussive envelope (see definstrument).
;;;
;;; The individual beat is repeated at a rate 'r' (Hz) over a
;;; specific time period [see (define jcrcuve) ].
;;;
;;; A number of patterns in geometric relation are constructed. Each
;;; of this patterns has a different envelope for the amplitude (overall
;;; amplitude gaussian) which furthermore be summed and multiplied to
;;; create a single beat.
;;;
;;; When these patterns are combined, they create a perception illusion
;;; of tempo increasing, when in reality , tempo remains the same.
;;;
(define simpleparad
(lambda (notes r)
(with-sound()
(let ((sta 0.00)
(sta2 0.00)
(rhy (/ 1 r)))
;;;
(do ((i 0 (1+ i)))
((= i notes))
(begin
(let ((rhythm (+ 3.35464e-4 (* rhy (jcrcurve i notes)))))
(beats sta rhythm 600 0.25)
(set! sta (+ sta rhy))) ))
;;;
(do ((h 2 (* 2 h)))
((= h 32))
(begin
(set! sta2 0.0)
(do ((i 0 (1+ i)))
((= i h))
(do ((j 0 (1+ j)))
((= j notes ))
(begin
(let ((rhythm (+ 3.35464e-4 (* (/ 1 (* h r)) (jcrcurve i notes)))))
(beats sta2 rhythm 600 0.25)
(set! sta2 (+ sta2 (/ 1 (* h r)) ))) )
))) )
))
))
;;;
;;; (simpleparad 33 0.425)
;;; (simpleparad 10 0.5)
;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; Complex case:
;;; ===========
;;; This case is shown on J.C. Risset's Pradoxical Sounds
;;;
;;; The concept for the complex case is almost the same although, the
;;; illusion is achieved by having the listener focus on the beat which
;;; has the loudest amplitude. Here we use a normal curve [(ampgaussian)]
;;; to handle the amplitude on each of the patterns. By the same token
;;; amplitudes are further superimposed against each other and
;;; against rhythm beats.
;;;
;;;
(define complexparad
(lambda (notes r)
(with-sound()
(let ((sta 0.00)
(sta2 0.00)
(rhy (/ 1 r)))
;;;
(do ((i 0 (1+ i)))
((= i notes))
(begin
(let ((rhythm (+ 3.35464e-4 (* rhy (jcrcurve i notes)))))
(beats sta rhythm 400 (* 0.25 (ampgaussian i notes)))
(set! sta (+ sta rhy))) ))
;;;
(do ((h 2 (* 2 h)))
((= h 32))
(begin
(set! sta2 0.0)
(do ((i 0 (1+ i)))
((= i h))
(do ((j 0 (1+ j)))
((= j notes ))
(begin
(let ((rhythm (+ 3.35464e-4 (* (/ 1 (* h r)) (jcrcurve i notes)))))
(beats sta2 rhythm 400 (* 0.25 (ampgaussian j notes)))
(set! sta2 (+ sta2 (/ 1 (* h r)) ))) )
))) )
))
))
;;;
;;; (complexparad 66 1.25)
;;; (complexparad 66 1.45)
;;;
;;;
;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
