A core material for a vacuum insulation material is produced by forming under heat a mat of inorganic fibers with an uncured, thermosetting organic binder adhered thereon into the core material while pressing the mat for at least 30 seconds such that a density of the mat increases to 150 to 400 kgm3. In general, a virtual group of playback devices or users of the playback devices is formed and managed by a virtual group control function. The automated system initiates selection from inventory or purchasing of materials to be used in the manufacturing operations, creates all manufacturing CNC programs for the components to be manufactured and downloads to CNC from manufacturing equipment. Clearing the address table causes a discovery process to fill the table to begin immediately. A compression spring resists longitudinal movement of the wire seating and wire cutting blades in the direction of the base of the cartridge by seating pressure applied to the cartridge.