A side frame for a loudspeaker rigging system has a frame structure mountable to the side of a loudspeaker, and links associated with the frame structure for linking together the corners of the frame structures of vertically adjacent side frames. The links associated with each side frame structure include a pivot link and splay adjustment link, each of which has a top extended end and a base end. Stow channels, which are preferably located in the bottom corner regions of the frame structure, contain the pivot link and splay adjustment link in the frame structure. A gripping structure associated with at least one, and preferably each link of the pivot and splay adjustment links allows a user to easily maneuver a link from its stowed to its deployed position. The extended end of the splay adjustment link includes at least two, and preferably an array of pin holes which can selectively be matched with one pin hole within a row of pin holes in a bottom corner region of the side frame to permit adjustments of the splay angle over a range of angles. Suitably, two rows of pin holes are provided in the top extended end of the splay adjustment link to permit multiple and incrementally small splay angle adjustments.In the preferred embodiment, the frame structure is comprised of an assembly of parts comprised of a center core structure sandwiched between two side plates.