Loudspeaker voice coil bobbins

A voice coil bobbin for a loudspeaker for driving a sound-radiating diaphragm to reciprocate along an axis, the voice coil bobbin extending axially along the axis and circumferentially around the axis, the voice coil bobbin having at least two axially-spaced rows of perforations extending circumferentially or at least partly circumferentially around the axis, adjacent rows being rotated relative to each other such that adjacent perforations overlap circumferentially to form arcuate spars therebetween disposed circumferentially around the voice coil bobbin, each arcuate spar being adapted to flex, cantilever-fashion, in an axial direction in response to the voice coil bobbin being driven axially and allowing the axial length of the voice coil bobbin to vary, in which the overlap between adjacent perforations in adjacent rows is such that the length of the arcuate spars is at least 25% of the circumferential length of the adjacent perforations.