The late Dennis Kleitsch, who came up with the bass mod for La Scalas, typed up these directions for building LS cabinets.
(edit- is this better?)
Just attach a large scrap to the rip fence (my fence had two key-hole slots, the aux fence was attached with two #8 pan-head sheet metal screws). Feed the stock in vertically, pushing one after the other, using a large piece of scrap to push the last piece of stock. Cut all the ramps in one piece, then rip down to the width. Piece of cake (I built 24 LS with a cheap Sears saw).
Cut all 22-1/4" items without moving the fence, box will be square that way (rip oversize and re-saw if need be). Set the blade to 30*, take your time and get it right. If your blade heels (most do), set the fence to be parallel with the blade. The set on the teeth should just shave the aux fence. An auxillary fence is used to cut the 60* angle, the board will be fed vertically into the blade. Use the next chamber angle board as a push board, then the ramps, then an absolutely square push board will be needed for the last item. Cut all ramps in one piece at 60* and 30*, then re-saw to 3" (add for your saw kerf). A brad nailer is used on the 60* boards to attach to the chamber sides and (later) make the front angle. I use 8d galvanized casement nails for about everything else. With skill they can be driven flush without a nailset and leave no mark on the wood. Lay the chamber sides into a grove on the saw top. Lay the chamber angle sides on top and square up with the table edge. Tack in with two wire brads, then carefully pull appart. Apply glue to the joint, re-assemble, tap the two brads in all the way, and check to see if it is still square. Nail the rest of the joint with brads. Check for square (easier to fix now than later). This is all much easier than it sounds. Set the T-nuts (I use a C-clamp), make sure they have threads!. Glue and nail the ramps onto the motorboard. Draw lines on the motorboard so your nails will actually hit the ramps. Blunt the point of the nails to avoid splitting. Dry fit. Drive two nails for each ramp, but only a fraction of an inch into the ramp. Mark the order of the ramps on the motor board. Knock apart. Glue. Drive the nails home, add a third nail to each ramp if you like. Use a Surform body file if you need to loose any wood that hangs out past 22-1/4", the points should hang over the 15-1/4" width. Line up the motorboard assembly with the back and draw nail lines for the ramps. Cut the deflector shorter than 13", it will save a lot of grief. Attach to the back. Are your nail lines going to be visible? Dry fit the side/angle assembly to the motorboard with a couple of blunted nails. Start all the nails you will use. Glue. Make sure its square. Drive home the nails. Repeat for the other side/angle assembly. Use a small spacer to keep the front angle open while you work. When the whole mess is square, remove spacer and use the brad nailer on the front angle. If the doghouse is not square at this point, stop and fix it. Dry fit the chamber bottom to the back with two or three nails, then dry fit the doghouse to the bottom with a couple of nails. Glue on the bottom. Glue on the back. Dry fit the chamber top. Glue on the top. I use a two-flute panel cutter with a guide bearing to cut the woofer mounting hole in the bottom, use the brad nailer to tack on a guide for the router to follow the front edge of the cut.