Drawing for Altmann BYOB speaker 80x40 cm. You need 11 pc. 80x40 cm (31.5" x 15.75") panels (preferrably spruce / pine-wood) for a stereo pair incl. open baffles. 400,00 -> 16" You can also make them 32" x 16". Thickness I use is 18mm = 0.71" No matter what your standard wood panel thickness 'd' is (i.e. 0.8" or 1") all that changes is the dimension of the top and bottom panels (16" x 16-2d"). The front and side panels all stay 32x16" resp. 80x40 cm. Front View: Side View: 00 2.9" 3, Ø7 ,00 5.7" 5 Ø14 Tilt, as you like crossover 00 , 284 800,00 -> 32" Ø 11.2" 0 ,0 20 Ø1 400,00 -> 16" bass refl. port 4,7" 400,00 d I have lacquered boxes and baffles inside outside with colophony dissolved in turpentine. The side- rear and front-panels have wood-slabs glued in place as reinforcement. Fluffy blanket is tacked to the inside of each box. I use small wooden feet (3 per box). Reflex port can also be in rear panel.