Having acquired all the materials except the driver and amp, I started construction. First order of business was to determine final measurements. I came up with the following:

Sonotube cut to - 5' 3 3/4"
Port cut to - 24 1/2"
Legs cut to - 6 1/4"
Endcaps would be 1.5" thick with 1" of each inside the Sonotube and 1/2" of each outside the Sonotube
Port - 3 1/16" IR; 3 5/16" OR
Sonotube - 9 6/16" IR; 9 8/16" OR

First step was to cut my half sheet of MDF into 19.75" squares and glue them together in pairs. I constructed some home made circle jigs (see circlejigs jpg). They managed to survive to the end and completed the job plenty good enough. I then cut one of the ends of the Sonotube square. This was done with the method I saw on Patrick Sun's web site. With my 1.5" thick pieces of MDF made, it was time to cut them to fit in the Sonotube. I started by using a drill press to setup a perpendicular guide. This guide was used to make sure I drilled as close to perpendicular as possible center holes for the circle jig, to make sure the center was at the same place on both sides of the endcap. With perpendicular center holes drilled, I cut them to a diameter I new would be to big, well over 19". I set the router bit to a 1" depth and began to trim the end cap down until it just fit in the Sonotube. I immediately cut the other endcap to the same diameter. This was done because I didn't want to change the circle jig's setting and have to find that exact radius again. This resulted in the second endcap having a ridge that needed to be trimmed off. The reason for telling you about this is what happened next.

The ridge was just slightly smaller than the 1/4" bit in the router. So set the router to cover it and trim it off. I expected it to just come of as dust. Wrong. The initial drop into the ridge went to dust, but as soon as I started trimming around the endcap, it just started peeling off intact. I have no idea why this happened. Up there as one of the most bizarre things I've ever seen.

I guess I'll also mention now that my dad had purchased a wet dry shop vac about a week before we started construction. If you have someone to give you a hand when using the router on MDF I highly recommend getting one. We used it to suck up the MDF dust as we cut. Didn't need masks and really reduced the mess made in the garage.

Anyways, I flipped one of the endcaps over and started to trim the remaining 1/2" down until it had about an 1/8" of overhang on the Sonotube. Transferred the jig to the other endcap and cut it to match. In each case as the endcaps got closer to the right size I went from taking 1/8" off at a time to taking less than a 1/16" off at a time. I salute anyone brave enough to go straight to their measured size, cut and have it fit right.

With endcaps cut to size time to cut the port hole. Luckily I had a bunch of extra MDF from some desks we made earlier. I measured and started cutting test holes to the outer diameter of my port. With the outer radius found on the jig with test cuts I transferred it to the actual top endcap and made the cut to a depth of 3/4". I then made the jig a 1/4" smaller and made another cut. I set the radius on the circle jig to a length I knew to be slightly smaller than the inner radius of my port. I verified this with a test cut. With this radius on the jig I began cutting the actual endcap (which of course was now turned over). I set the depth of the router to just over 3/4" and made the cut. This popped out a disc that was 1.5" thick with 3/4" at the outer port diameter and 3/4" slightly smaller than the inner radius of the port. Using one of the test cut pieces that would just fit over the port I trimmed one end of the 6" PVC pipe square, measured out 24.5" and cut the other end square at that length. I sanded down and cleaned up the port hole into which I glued the port. I used Bulldog polyurethane construction adhesive to glue the port into place. This was done how you would expect, except I also drilled 4 holes in the port just big enough for a finishing nail. After the glue and port were into the endcap I tacked it in place with 4 finishing nails (which were tapped flush using a center punch). I also caulked around the port on the inside of the endcap. After the glue and caulk dried, I used a flush cut router bit to trim the top of the port hole flush with the port. Which is easier than trying to cut it dead on initially and why I was cutting to just under the port inner radius above. After that, I made as big of a round over as I could on the port and just barely rounded over the edge of the top endcap.

By this time the driver had arrived, so I test cut some holes for it. Miraculously I had a perfect fit on the second test cut. Using my set circle jig I cut the driver hole. Using the driver I then marked all the driver mounting holes. I also measured out and marked where the three holes for the threaded rod would go through the bottom endcap and attach to the legs. I drilled all these holes using a drill press. On the inside of the endcap I drilled slightly larger holes that would just barely fit the widgets I had purchased for securing the driver. They are like t-nuts but with a larger solid lip, a little deeper and thicker. Hammered them into place and then sealed them up good with silicon caulking.

On to the final step in endcap construction. The brackets to hold the threaded rod to the top endcap. Had some 3/8" steel lying around in the garage, so using an acetylene torch I cut them to just over 2" by just over 5". Used a 6000 rpm hand grinder to smooth there edges up. Then using the drill press drilled 4 holes in each for screws to secure them to the top endcap and one in each for the threaded rod (3/8"). Using a tap and die set I threaded the hole for the rod. I drilled three holes about a 1/2" deep into the top endcap wide enough to accept the threaded rod in the positions where the brackets would be mounted. Using the bulldog glue and screws, I mounted the brackets to the top endcap in line with the holes I just drilled. I cut the threaded rod to a length that would have around 1" sticking out the bottom endcap. Then I put some more bulldog glue in the holes for the threaded rod and screwed them in after which I secured them to the bracket with a nut (over kill I know, ain't it great).

If you aren't completely lost yet, take a look at EndCapsConstn jpg and it will hopefully make some more sense.

Now onto the plate amp mount. I took two pieces of MDF that were about 20" wide and 10" deep. Found the center along one edge and measured half the plate amps width on each side of that mark. At the center mark I measured back how deep I wanted it to be (the depth of the plate amp; not including the heat sink fins that show on the outside; and added 3/4" to make sure the amp wasn't touching the sonotube). I used this as where the apex of the circle (ie the Sonotube) should be. To make this cut that the sonotube would fit into, I measured back at a right angle to the edge the plate amp would mount to, from the decided upon apex mark to the outer radius of the Sonotube. This of course went well past the 10" of my piece of MDF so I had to clamp it to a table and clamp a scrap piece of MDF to the table that the circle jig could have its center nail attached to. I then made the cut and repeated the process on the second piece. So I didn't have just a square box sticking out of my tube, I decided how far back on the circles I had just cut I wanted to go with an angled cut. I cut from the edges of where the plate amp would be (no decision to be made here, dictated by the plate amp size) to that point on the circle (which has a maximum, but was up to me where between right angles and that maximum I wanted to cut) with a table saw. These two pieces also had sixteen 3/8" holes drilled into them. I cut two small pieces of MDF (about 2.5" deep) that would connect the two pieces described above in a manner that created a box the right size for the plate amp, with angled edges coming off. The angled edges besides making the mount look better, provided more air for the plate amp. This was mounted to the Sonotube a few inches from the bottom with 6 screws that where then caulked from the inside. Finally two small squares of a thin wood (about 1/8" thick) where cut and mounted to the side angles of the plate amp mount. Check out any of the jpgs with amp in the file name to see the final result. Sorry, but I never got around to taking any photos of the plate amp mount before I had the sub finished.

I primed the outside of the top and bottom endcaps along with the inside of the port (which is why it looks like the port has a dent in it in the picture, that's actually just the paint and lighting). Cut the Sonotube to the correct length. Glued the top endcap into the Sonotube and used some finishing nails to tack it into place (making sure one of the threaded rods was in line with the center of the plate amp mount). I crawled inside the Sonotube with a flash light and caulked the inside of the top endcap. This was not fun. I barely fit in the tube and had to crawl in until the bottom of the Sonotube was at the middle of my thighs. Add to that poor lighting, the difficulty of getting the caulking gun around the port and threaded rod and it's almost a miracle I succeeded.

I used the left over Sonotube to cut really roughly three layers of insulation into circles an inch or two wider than the Sonotube. I cut holes in the middle of each piece slightly smaller than the port. I pushed them into the sonotube, punching the threaded rod through in the appropriate place. Using two broom handles I worked each piece of insulation to the top of the tube around the port. After I had the three pieces up there it was just over a foot thick. I used some caulking and the threaded rods to line the rest of the tube with a double layer of polyfill. The pollyfill layers were sewed together in a few places before they went into the tube, and then caulked to each other and to the tube in a few other places after they went into the tube. Take at look at TubeInside jpg to see the end result.

I bought a piece of hardwood that was about 20" long and 1.5" square for the legs. I cut it into 3 pieces 6 1/4" long. I drilled a hole in the center of each just big enough for a 3/8" coupling nut. I glued the coupling nuts into the legs with bulldog glue. I placed two nuts and a washer on the threaded rods before I glued the bottom endcap in place. The bottom endcap was then glued and put into the sonotube. Before the glue dried it was rotated until the one rode lined up with the center of the plate amp mount again. At this point the legs where screwed onto the threaded rod until they were nice and snug. I tightened the nuts on the inside down, which straightened the slight angle the legs had out. I then caulked the inside of the bottom endcap and around where the threaded rod went through the endcap. This also wasn't fun.

I primed the entire tube and plate amp mount (didn't want any brown showing through the sock fabric) and finished priming the top and bottom endcaps along with the legs. After that I painted the top and bottom endcaps and top and bottom of the plate amp mount.

Finally time to do the final assembly. I used some 12 gauge wire to connect the voice coils of the tempest in parallel. This wire was then caulked onto the driver frame so it couldn't rattle against anything (this wire was cut to a length that just allowed this). I ran foam weather stripping tape along the drivers lip. After this was done I drilled a hole through the Sonotube inside the plate amp mount that was just big enough for the 12 gauge wire and threaded the 12 guage wire I had left through it. I then attached the 12 guage wire to one of the Tempest's voice coils and screwed it into place. With the Tempest in place the wire was pulled, where it came out of the Sonotube, until it was snug. That hole was then caulked as well. The wire sticking out of the Sonotube was cut to length and attached to the plate amp. Finally the plate amp was screwed onto the plate amp mount and there was nothing left to do but turn it on.

This had to be the worst part about building it. Had the same look on my face my dad did after he finished assembling the first computer he bought in pieces. Nothing left to do but see if I did it right. As it would turn out, nothing to worry about, sounded great. Although since all the silicon wasn't completely dry yet, I didn't push it. As it would turn out there was a ground loop problem so I never really turned the sub up until I got a multi plug adapter and cut the ground prong off (by which time the silicon we definately dry). This solved the ground loop problem and I could then turn the crossover and the volume on the plate amp up without getting a nasty buzz. I was now quite happy with my new toy.

Before I get onto a more detailed description of how I think it sounds there was one thing left to do. The sock to finish it's appearance. The sock was made out of a textured fabric that was stretchy one way. In the none stretch direction (did have a little stretch though) I cut it slightly (and I mean slightly, 1/4" or less) shorter than the Sonotube height. In the stretch direction it was already almost 6" shorter than the tubes circumference. I then sewed a seam that would be the length of the distance between the top of the plate amp mount and the top of the tube. This was test fit with the seam positioned to line up at the center of the plate amp mount. To get the right sized hole in the sock for the plate amp mount I did the following. Measured the length of the curved part of the plate amp mount. Using a ratio of the unstretched socks circumference to the Sonotube's actual circumference I determined how wide the unstretched hole would need to be. I divided this in half and subtracted an inch off. Since the sock would barely be stretching vertically I just measured the height of the plate amp mount for that dimension of the hole (but like the width I subtracted an inch from it). I cut flaps back starting half an inch bellow where the seam ended to half the size I determined above (the flaps where actually cut right off). The removal of an inch from all directions of the plate amp mount cut out was so a hem could be put on the top and bottom of the plate amp mount hole and still fit. And also to allow flaps of the right size to be sewed on with a seam just under an inch up from where the side slope starts. These side flaps where made slightly smaller than their needed final dimensions (with hems on three of the sides) and sewed onto the sock. The sock was pulled on the tube and carefully hot glued into place. This was done top and bottom, to connect the flaps to the plate amp mount, and to attach the section between the bottom of the tube and the bottom of the plate amp mount together.

Finally, it was all finished. If you haven't already, check out the rest of the pictures.