I have built several subwoofers using the Parapix amplifier. Featured here is a subwoofer that I built for my older son. He has very limited space so a dual purpose piece of furniture was in order. It uses a Madisound 1252DVC with one voice coil being driven by each of the two channels of the Parapix Amp.
This sub is constucted of 3/4 inch particle board laminated with 1/4 inch oak veneer plywood. The top is covered with a piece of Dupont Corian. This provides an almost bulletproof tabletop and the downfiring woofer protects it from wayward feet and probing fingers. Perfect for a GenX bedroom.
The Parapix amp is sold by Apex Jr. and is a dual output mono amp providing approximately 60 watts in each output. This makes it perfect for a dual voice coil woofer. It is mounted in it's own enclosure that is separate from the main speaker enclosure. It has an adjustable low-pass crossover(60 to 120Hz), a fixed hi-pass crossover and a volume control and can handle line level or speaker level inputs.
The total cost of this sub was less than $100. That's hard to beat. The amp and transformer is about $35 from Apex Jr. and the driver from Madisound was about $50. The wood was laying around but if it had to be purchased it would cost about $35. Corian is very expensive stuff but the leftovers from kitchen remodel projects are often made into cutting boards or left behind for the homeowner to use. I picked up several pieces for free and used a white sink cutout for the top of this cabinet. It machines a lot like a hard piece of wood and can be sanded to as smooth a finish as you like.
I have made a quik drawing of the construction. The exact dimensions are not critical, so this should be sufficient information for most people to duplicate the box. The sides of the box are made from 3/4 inch particle with a layer of 1/4 inch Oak veneer plywood on top of that. Each corner has a piece of solid Oak, 1/2 by 1/2 inch, let in to cover the raw edge of the plywood. The top and bottom are made from one layer of 3/4 inch particle board. A layer of 3/4 plywood was laminated to the speaker baffle and everything was stiffened up with braces about 4 inches high and the width of the box. The net volume of the box is just about 3 ft3. It is stuffed just full of fiberglass insulation.
