if you want to change VELOCITY of a technique... 

 

(defun replace-velocity-of-a-technique (omn-list &key technique velocity)
   (flatten (loop for i in (single-events omn-list)
              when (equal (car (omn :articulation i)) technique)
              collect (pattern-map (list (list (list '? technique) (list velocity technique))) i)
              else collect i)))


(replace-velocity-of-a-technique  '(e. c4 p tasto d4 ponte e4) 
                                  :technique 'tasto 
                                  :velocity 'f)

 

Thank you André.

 

I've made that based on you code for replace pitch on technique:

 

;;; REPLACE-PITCH-OF-A-TECHNIQUE
;;; Based on code from AM. (replace-velocity-of-a-technique)
(defun replace-pitch-of-a-technique (omn-list &key technique pitch)
   (flatten (loop for i in (single-events omn-list)
              when (equal (nth 3 i) technique)
              collect `(,(nth 0 i) ,(rnd-pick pitch) ,(nth 2 i) ,(nth 3 i))
              else collect i)))


(replace-pitch-of-a-technique  '(e. c4 p tasto d4 ponte e4) 
                                  :technique 'tasto 
                                  :pitch '(g6))


(replace-pitch-of-a-technique  '(e. c4 p tasto d4 ponte e4 d4 tasto f5 tasto)  
                                  :technique 'tasto 
                                  :pitch '(g4 e5 a6))

S.