BillFitzmaurice.info

My journey with Bill's plans began with the T39, which was the very first build I ever attempted. After that, I decided to take on another project, and these two cabinets represent my second and third builds. It's been a great learning experience, as they turned out significantly better than my first one. I've definitely picked up a few useful tips and tricks during the process.

I've found that Bill's instructions are incredibly thorough, and I typically stick to them quite closely. However, I do enjoy making a couple of minor modifications. For instance, I always make a point to add a reducer in some form. This extra piece helps to keep the chamber perfectly square and adds a significant amount of solidity to the overall structure.

For these specific cabinets, I decided to use LAB12 drivers. Unfortunately, I made a common rookie mistake by relying on the enclosure information from Parts Express instead of double-checking the manufacturer's official website. This oversight meant my reducer ended up being pushed all the way to the edge of the cabinet, which unfortunately prevented me from installing the recessed side handles I had originally planned. As a result, I chose to go with heavy-duty flush-mount handles, though I'm still not entirely convinced they were the perfect choice.

I put a tremendous amount of care and effort into ensuring these cabinets are as clean and solid as possible. While I don't consider myself a technical expert in acoustics or a hardcore audiophile, I am extremely particular about build quality. In my opinion, the most crucial part of these designs is how the braces connect. If those connections aren't perfectly secure, the entire cabinet is prone to rattling, and that's something I work hard to avoid. I may ask silly questions along the way

Welcome back Kent! All great ideas. LAB drivers, in any flavor, are excellent performers. Can't wait to see what you come up with.

Thank you Radian! Yeah, so these are being made for someone and I quite honestly can't do them much less than a LAB12. I mean, come on...

I do have to stop here and say I appreciate the drawing guide that Bill has with the designs. They are spot on.

I use a CAD program to get me numbers that I like to cross check, even though this isn't a tough build. I'm a bit nitpicky with 1/32nds and all. I prefer to map everything out in CAD and recheck while I'm building.

One thing I deviate from is that I don't put the side panel on first. I wait until everything on the inside run is complete, then I sandwich both outsides at the same time, roughly. So basically the first thing I put together is the baffle chamber with the drive anchor and retention blocks.

Circle jig is necessary IMO.

Baffle chamber is assembled, and I'm now on to the bracing. I'll reiterate, I think the most important pieces on these builds are the solid connections of the braces to the body. I’m focusing on a thin, even bead and a strong, consistent clamp to activate the polyurethane and fill any micro-gaps.

I reverse my 5 and 7 panels from the pdf file. I like to get that front access panel just right. I have Rhino3d CAD and re-did all of the measurements to get accurate measurement of that front panel. I seem to have it dialed in, this is the third one I have done like this and it seems to have worked.

I'm going to try to explain my procedure for my access panel, though some of you probably already do this. It's just one of those nitpicky things I do, I like my reveals tight and even. I start off with the actual door access panel to size and place it centered, or wherever (in tubas case), then I add some scraps to the sides with a few business cards for gapping. You can use playing cards, this is just what I had on hand. This gives me my gapping I want to see around the door, so adjust your amount of cards for such.
Remove the cards and panel and rough cut out to size with a jigsaw. Lastly, I bring it over to the flush cut bit on my router table and flush it out. Once done, I have some rounded inside corners, I personally like them, so I leave those and blunt the edges of the door to match. I have a BOSS for that.

Looks good!

I almost always will miter fold pieces like this. I'm assuming some of you good builders here will do the same. I make sure that angle is spot on. Otherwise, it's junk

While I was waiting for the miter fold glue to cure up, I decided to tackle the handles on the top, bottom, and back. 16 handholds total to cut. I made a jig.

After the handholds, one of the most important steps IMO is recessing that speakon connector. Hopefully the pictures will explain it. The speakons will be on the top of the cab on the back panel. Plans showed it on the bottom, and I just didn't want to see a wire hanging there in the back. I made it fit

Kent your build is looking great. Wish I had the skills and tools. I have qty t39 with KappaLITE 3012 drivers I bought used.

Are you using the specified Baltic Birch wood?

Also curious why you went with lab 12? The kapplites are very popular and significantly less weight. I just read lab 12 is 24lb.. Wow!

I always use Baltic Birch. Most definitely the material to use. I know I didn't have to on Titan's, but the cost difference isn't that significant.

Kappalite I might use next time. No reason, just picking what I thought was a high quality driver for the enclosure.

KentWhitten wrote: ↑Sun Nov 09, 2025 10:21 am I always use Baltic Birch. Most definitely the material to use. I know I didn't have to on Titan's, but the cost difference isn't that significant.

Kappalite I might use next time. No reason, just picking what I thought was a high quality driver for the enclosure.

Gotcha! Have you decided what amplifier you will be using for these yet?

FWIW the LAB became a viable option when neo driver prices went nuts. LAB prices are up too these days, so shop around for equivalent neo drivers if weight is a concern.