Methods, kits, systems and fabrications of home theater presentation rooms, audio listening rooms, and other types of rooms having acoustical panels (collectively, "acoustical-paneled rooms") are arranged inside existing wall structures, such as in a house. The component acoustical panels and bridging structures, such as vertically oriented columns, are arranged and constructed to permit a particular assemblage of such components to be able to extend across a range of wall widths, or spans. This is achieved by having the panels variably spaced from the centerline of the columns, to form gaps, with the columns nonetheless covering the edges of such panels and the gaps. In preferred embodiments, a particularly strong and easily assembled column assembly is utilized.