;; (dseries length start step)

;; demand rate arithmetic series ugen.

;; length   - number of values to create
;; start    - start value
;; step     - step value

;; The arguments can be a number or any other ugen

(let* ((a (dseries 15 0 1))
       (t (impulse kr (mouse-x kr 1 40 1 0.1) 0))
       (f (mul-add (demand t 0 a) 30 340)))
  (audition (out 0 (mul (sin-osc ar f 0) 0.1))))