;;; ADD-RND-DUST TO LENGTHS
;;; this function adding RANDOMLY some "dust" to the LENGTHS, so it will be like a little rubato,
;;; or "humanizing"-effect. the ADD-SPAN is in percent (0.1 = 10%) on each length-value.
(defun add-rnd-dust (omnseq &key (span '(0.1)) (seed nil) (quantize '(1 2 3 4 5 6 7 8 9)))
(let ((rhy (omn :length omnseq))
(sp))
(progn
(setf rhy (loop
with cnt = 0
for i in rhy
do (setf sp (nth cnt sp