methods and apparatus for increasing the efficiency of a voice coil motor are disclosed . according to one aspect of the present invention , a cylindrical and radially symmetric vcm includes a plurality of sets of magnets , and a single coil . the plurality of sets of the magnets are each arranged in an array configuration , and cooperate to form a magnetic field . the coil receives current and has a plurality of windings . a first space is defined within the coil , and the plurality of sets of the magnets are arranged such that a first set of the magnets is positioned within the first space and a second set of the magnets is positioned external to the coil .