While it may be many years before high resolution active acoustic boundaries will be widely available, accurate sound-field control presents an interesting theoretical problem. We investigate and compare several different methods, including existing methods and two new ones, that aim to find the driving functions for sources on a general boundary, such that any given sound-field is reproduced as accurately as possible everywhere within. The methods considered include High Order Ambisonics, Wave-fields, boundary element modeling, a modal boundary decomposition approach, and pressure control points. Finally a method is presented, referred to here as Distributed Modal Constraints, in which multiple regions are constrained by modal expansions simultaneously.