Clic and pop in the generation

[Brodvd]

Problem

Between the segments generates (the notes) there are clics and pops.

[Brodvd]

(defun note-with-envelope (freq dur)
  (let ((att 0.01)   ; attacco 10ms
        (rel 0.04))  ; rilascio 40ms
    (env (osc (hz-to-step freq) dur) att rel dur)))

(defun generate-melody (length)
  (if (<= length 0)
      (osc 0 0)
      (seq (note-with-envelope
             (midi-to-hz (random-note))
             (random-duration))
           (generate-melody (- length 1)))))

[Brodvd]

$nyquist plug-in
$version 4
$type generate
$name (_ "Melodia Casuale")
$copyright (_ "GNU General Public License v2.0")

$control Gen (_ "N. Note") int "60 (Max)" 30 1 60
$control Choice (_ "Tipologia di generazione") choice ((_ "Solo Toni") (_ "Toni e Semitoni")) Solo Toni

(defun random-note ()
  (let ((notes (if (equal Choice "Solo Toni")
                   '(60 62 64 65 67 69 71 72)
                   '(60 61 62 63 64 65 66 67 68 69 70 71 72))))
    (nth (random (length notes)) notes)))

(defun random-duration ()
  (let ((durations '(0.5 1 1.5 2)))
    (nth (random (length durations)) durations)))

(defun midi-to-hz (midi-note)
  (* 440 (expt 2 (/ (- midi-note 69) 12.0))))

(defun note-with-envelope (freq dur)
  (let* ((att 0.01)
         (rel 0.04)
         (main (- dur (+ att rel)))
         (main (max main 0))
         (env-shape (pwl 0 0 att 1 (+ att main) 1 (+ att main rel) 0 dur)))
    (mult (osc (hz-to-step freq) dur) env-shape)))

(defun generate-melody (length)
  (if (<= length 0)
      (osc 0 0)
      (seq (note-with-envelope
             (midi-to-hz (random-note))
             (random-duration))
           (generate-melody (- length 1)))))

(mult (generate-melody Gen) 0.5)

[Brodvd]

$nyquist plug-in
$version 4
$type generate
$name (_ "Melodia Casuale (Fase Continua)")
$copyright (_ "GNU General Public License v2.0")

$control Gen (_ "N. Note") int "60 (Max)" 30 1 60
$control Choice (_ "Tipologia di generazione") choice ((_ "Solo Toni") (_ "Toni e Semitoni")) Solo Toni

(defun random-note ()
  (let ((notes (if (equal Choice "Solo Toni")
                   '(60 62 64 65 67 69 71 72)
                   '(60 61 62 63 64 65 66 67 68 69 70 71 72))))
    (nth (random (length notes)) notes)))

(defun random-duration ()
  (let ((durations '(0.5 1 1.5 2)))
    (nth (random (length durations)) durations)))

(defun midi-to-hz (midi-note)
  (* 440 (expt 2 (/ (- midi-note 69) 12.0))))

(defun make-note-segments (n start)
  (if (<= n 0)
      '()
      (let* ((dur (random-duration))
             (midi (random-note))
             (freq (midi-to-hz midi))
             (att 0.01)
             (rel 0.04)
             (main (max 0 (- dur (+ att rel))))
             (env (pwl 0 0 att 1 (+ att main) 1 (+ att main rel) 0 dur))
             (seg (at start (mult (hzosc freq *sine-table* dur) env))))
        (cons seg (make-note-segments (- n 1) (+ start dur))))))

(setq segment-list (make-note-segments Gen 0))

(mult (eval (cons 'sum segment-list)) 0.5)