This how2everystep DIY video shows you how to cut, build,
paint and assemble a high quality ported subwoofer enclosure / box from MDF. I have used an 8" subwoofer for this build.

Every Step Summary
Step 1: Check MDF fitment & trim to suit
Step 2: Speaker hole cutting & routing
Step 3: Port & corner section making
Step 4: Screw hole drilling & assembly
Step 5: PVA seal the MDF
Step 6: Fill screw holes with filler & then sand
Step 7: Painting
Step 8: Cable terminal block hole cutting
Step 9: Fit feet
Step 10: Fit speaker & cable terminal block

Tools Required
18mm MDF
Subwoofer Driver
Cable terminal block, speaker cable, feet
PVA glue, car body filler
Wood screws
80 grit sand paper
Paint, Paint roller & brush
Electric Drill
Circular Saw (or get cut by hardware store)
Router & hole cutting template