It is usual to set single-point noise controller at each point in order to cancel noises at multiple cancelling points. How should we adapt controllers in such a case? The easiest way is to let them work individually, though it is possible to use all the error signals for one controller. In this case, there is a promblem that the controllers do not necessarily converge. In this paper, we consider the conditions of the paths under which the controllers converge when they work individually.