Building the Subwoofers

Front baffle design

On to the separate parts, let’s start with the front baffle. This baffle consists of 2 pieces of Birch ply. One outer panel is 19 mm Birch ply and the other inner panel is 15 mm in thickness. The threaded rods are M8 rods, about 420 mm long. They are fastened to the inner panel of the baffle with T-nuts. I welded the T-nut to the threaded rod, drilled holes in the inner part of the baffle for the T-nut and rods and drilled the T-nut and inner ply baffle to fit a pair of small M4 bolts + nuts holding it in place.

Baffle design

The part of the baffle that’s visible from the outside. Generous rondovers are used on the left and right side as well as on the driver cut-out hole.

You can shift a bit with these bolt patterns. Just drill this inner baffle first (with an 8 mm drill) and use it as a template for all other panels that the threaded rods go through. After all holes are positioned drill these out to size to fit a M8 T-nut.

I routed one driver hole on my table and used that panel as a template for use with a copy bit for each successive panel that needed an equally sized hole. Use temporary fasteners to keep the panels fixed in place. Be aware to never to use the visual side of the panels for fixtures though. Once fixed like this it’s easy to drill the holes for the threaded rods too.

I’ll post a couple of pictures to show how I fastened the threaded rods to the baffle.

T-nuts welded to the threaded rod. Then drilled and fastened to the inner baffle with 2x 4 mm bolts and self locking nuts. The bolt type is Phillips Flat Head Machine Screws. Mounted flush on the other side of the panel with a countersink hole.

Here’s the outer panel with my notes still on it. You see I made a cut-out with a drill for the bolted T-nut construction to fall in. After that I glued both panels together and used a liberate amount of wood screws to fix them together permanently.

The Philips Flat Head machine Screws that lock the T-nuts can be seen next to each rod. Be sure to fix the inner panel with the smaller width (354 mm) on the side that features the roundovers on the outer panel. The side panels are 3 mm more in thickness due to the use of the outside logo ‘beauty’ panels. You can see the pencil marker line that’s free about 3mm of the panel. If you don’t use logo panels, the size of all inner panels can be changed to 360 x 360 mm (except for the brace). This size will leave a gap of 1 mm on all sides when everything is bolted together. Making sure it fits together easily. (adjust this size according to your own taste, you can make it a tighter fit)

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