If you have a RepRap, MakerBot, Up!, MakerGear, Ultimaker, or other suitable fused-filament printer, you can print and build this speaker for just under $100 in parts and materials. That includes speakers, hardware, wires, cable, plastic filament--everything.
The high symmetry of the dodecahedron is amenable to a modular design, and this one consists of four basic parts: the face modules, the vertex plugs, the edge gaskets, and the bezels. (NOTE: These models are also available on Thingiverse.) The speaker grilles are made from hardware store window screen cloth installed in the bezels using rubber spline and a screen roller tool, just like a residential window screen.
The assembled speaker array weighs 5.6 lbs, not counting the cable, and measures 7.5" across, from face to face, and 8.6" from point to point. The speakers are wired in a hybrid series-parallel circuit that brings the total array impedance to about 10 ohms (again not counting the cable) which should be a comfortable load for most amplifiers.
Non-printed parts ("vitamins")
12 pcs × speaker, square, ferrite 3", 8 Ohm, 3W, Jameco SP83W
10 ft × instrument patch cable, 18 AWG leads, such as Conquest Sound CS118
30 pcs × sex bolt (hehehe), combo truss head, zinc plated, 3/16" barrel, #6-32 × 3/8", Bolt Depot 14285
30 pcs × machine screw, combo truss head, zinc plated, #6-32 × 1/2", Bolt Depot 2887
60 pcs × split washer, #10, zinc plated, Bolt Depot 3023
108 pcs × wood screw, #4 × 1/4", black oxide or finish of your choice, such as McFeely's 0402-PSK
13 ft × screen spline, vinyl serrated, 1/8", black or color of your choice, such as Home Depot 3028737
3 sq ft × window screen, black or color of your choice, such as Home Depot 3003947
36 in × hook-up wire, stranded, 18AWG, white or color of your choice, such as NTE
18 in × hook-up wire, stranded, 18AWG, red or color of your choice, such as NTE
2 pcs × craft foam, adhesive-backed, 8.5 × 5.5" sheet, black or color of your choice, such as Fibre Craft
2 pcs × wire nut, orange, such as Ideal 73B
1 cu ft × glass wool, such as Owens Corning PINK
6 in × electrical tape
3D printer - I use and enthusiastically recommend the MakerGear Mosaic M1, but any RepRap-type fused-filament printer should work so long as it has a build volume of at least 122 × 122 × 14 mm. Mine is equipped with a 0.35 mm extruder nozzle and a heated build platform. I print onto a 1/8" aluminum plate covered in painter's masking tape. To make models (CAD), I use Google SketchUp Version 8 with D. Bur's su2stl plugin for STL import / export functions. To convert STL models to G-code machine instructions (CAM), I use Alessandro Ranellucci's Slic3r (v 0.7.1). To actually control the printer (client), I use kliment's Printrun. All of this is free software.
2D printer (laser or inkjet)
Multimeter & leads
Small butane torch, such as Bonjour Chef's Torch (optional, for flame-polishing)
Hole punch, 4.5 mm, such as Harbor Freight #97715 (optional, for punching holes in gaskets)
Spring steel shim, such as iSesamo (optional, but handy for removing parts from build platform)
Hex driver with basic bit set
#0 square drive hex bit (required for McFeely's wood screws)
Additional Phillips-head screwdriver (you will need two screwdrivers for tightening sex bolts)
Needle nose pliers
Screen roller tool (such as Prime-Line #P 7503)
Sharpie permanent marker
1/8" metal rod, 6+ inches (optional, for holding plugs during flame-polishing)
Long-sleeved shirt (for handling glass wool)
Latex, nitrile, or other protective gloves (for handling glass wool)
Plastic filament - My extruder takes 1.75 mm diameter filament, and I prefer to print in polylactic acid (PLA). Using my CAM settings, you will need 185 meters of filament which, at typical densities for 1.75 mm PLA, should weigh about 560 g. So a 1 kg spool should be plenty, if you only want to print in one color. If you're printing in multiple colors, you will need about 150 m / 450 g of filament to print the modules, 33 m / 100 g to print the bezels, and 3 m / 10 g to print the plugs. None of these filament estimates includes an allowance for misprints or other losses, and in my experience you will probably want to add about 10% to account for these. All my filament came from MakerGear.
1 pc × printable paper label, adhesive back, 8.5 × 11", 2 × half-page label each, such as Avery 8126
8 in × solder, 60/40 rosin core, such as Alpha Metals 13460
35 ft × painter's masking tape, 1.5", to cover build platform
Step 1: Prep the cable
The easiest way to remove the plug is to just cut it off a short distance behind the ferrule with a pair of sharp scissors. Toss it in your spares box and desolder the inch or so of attached cable when and if you use it, later. If the waste bothers you, of course, you can go ahead and unscrew the ferrule, cut away the heat shrink tubing, and desolder the connections now.
Once the plug is gone, slit the rubber cable sheath with a hobby knife for an inch or so at the end. Try to cut between the wires, but don't worry too much if you nick one. Once it's cut, grab the two halves of the split sheath and "banana peel" it back three inches, or so, exposing as much of the wire pair as you need. If you nicked the wires while cutting through the sheath, snip the ends off far enough back to remove the damaged part(s). Once you've got two inches of good wire pair exposed, trim away the excess sheath bits.
Tie a strain-relief knot in the cable another two inches back, or so. This knot, which is much too wide to pass through the narrow opening where the cable will exit the cabinet, will bear the weight of the hanging speaker.
Finally, strip about 3/4" of the insulation from each of the wires, exposing the copper strands.