anchor.diff:                      history +xdelaya+ +xdelayb+ +xadaptcoeffsa+ +xadaptcoeffsb+))
            (y (first  (frame-output frame)))
            (x (second (frame-output frame))))
  -    (declare (type (sa-sb 32) history)
  +    (declare (type (sa-sb 32) history x y)
                (type function update-x update-y))
       (loop with channels = (frame-output frame)
             for i below (frame-samples frame) do
  
positive.code: (defmethod predictor-update (frame
                               (version (eql 3950))
                               (channels (eql :stereo)))
    (declare (ignore version channels))
    ;; Seems like this function cannot be applyed to all channels
    ;; independently (like APPLY-FILTER)
    (let* ((history (zeros (+ +history-size+ +predictor-size+)))
  
negative.code: (defun make-predictor-updater (history delay-a delay-b adapt-a adapt-b)
    (declare (type (sa-sb 32) history)
             (type (sb 32) delay-a delay-b adapt-a adapt-b)
             (optimize (speed 3)
                       #+easy-audio-unsafe-code
                       (safety 0)))
    (let ((last-a   0)
          (filter-a 0)
          (filter-b 0)
  