Many components have buttons labeled midi or m adjacent to adjustments. These are used to assign hardware control over that adjustment (or rather, the value which that adjustment controls). While holding the button down with the mouse, move a midi slider or other device. From then on, that device will have control over the corresponding value. An adjustment can be freed from control by right clicking on the m button. These buttons will only respond to their most recent dynamic assignment, but a piece of hardware can control several different adjustments. This method of assignment is useful for quickly adding control to a newly created filter, or reassigning some unique input device like a ribbon pad or rangefinder.