This architectural drawing is SUB WOOFER & MAIN & DOWNFILL SPEAKER in detail AutoCAD drawing, CAD file, dwg file. A subwoofer is designed to produce music's bass and sub-bass, which are lower frequencies amplified by the woofer. A second main speaker that projects at a slightly different angle to cover a deeper area of the main seats is called a down-fill speaker. For more details and information download the drawing file.