Okay honestly, I did not complete all of the above steps in a single day.
From here on work at your own speed, this has been a month long project for me and I am still not 100% complete with it.
More sanding, I had about burned both brushes up in my dremel's motor.
Okay now to start making this thing into a recognizable shape - an enclosure.
Start with making a ring - a plunge router and a circle jig is highly recommend here
Dato the edge to staple the material too, and recess the subwoofer, it will look much cleaner in the final stages. In my enclosure it is 2 rings of 3/4" mdf.
Okay you then position the ring where you want it with some dowl rods. Using CA Glue - available at any good hobby shop - attach the ring to the back/bottom of the enclosure. Some activator will also aid to speed up this process. Sorry no pics of just this process - I was excited at this stage and forgot to stop and take pictures. You'll see what I'm talking about in a minute.
You can use fleece - choice for many years. I chose to use "ponte" it's a 100% polyester cloth. It is slightly thicker than speaker grill cloth and just as stretchy. Stretch your material snuggly over the ring and using the CA & Activator attach the material to the outter edges of the enclosure.
You should have something similar to this.
At this point you are going to need a stapler - I would suggest a pneumatic upholstery stapler. Shoot the cloth to the speaker rings dado edge. then trim the material from the center of the ring.
see the dowls