I am planning to build two powered THTLPs. Each THTLP will be built with a Dayton RSS315 HF-4 12" woofer and a Dayton SPA250DSP plate amplifier. I have the woofers, but the amps are on backorder and won't arrive until the new year.
I'm building the first one now; the second one may have to wait until spring when the weather warms up. The builds rely on PL Premium construction adhesive which is only rated for use in temperatures above -7 degrees C (19 degrees F). Because I live in Canada and work in an unheated garage, I'm racing to finish the first build before the temperature gets too cold. Also, my wife wants my tools out and her car back in the garage before the snow comes!
Progress to date
Here's what I've done so far, pretty much on a day-by-day accounting:
1) I picked up two 4' x 8' sheets of 1/2" Baltic birch plywood. The plywood was expensive --- CAD$160 (roughly US$125) per sheet. Because I don't have a truck, I had the lumber yard cut each sheet into:
- 1 x 18.5" x 72"
- 2 x 14.5" x 72"
- 1 x 24" x 48"
2) I used scrap lumber that I had laying around to build a number of jigs from the plans that Bill makes available. They've been invaluable. If asked, I would recommend making more of the panel jigs and circular saw sleds so that some could be dedicated to the different angle cuts that must be made.
Bill's didn't provide plans for a circle cutting jig, but I built one based on some I'd seen on YouTube. 3) I cut the front and back sides and marked out the lines for all of the panels.
4) I cut out and installed panels 1 and 2. I fastened the panels with brads and some strapping to hold them while the PL Premium cured.
5) I cleaned up the PL Premium squeeze out from the previous day with a sharp knife and a scraper. Then I cut panels 3 and 4 and installed them using PL Premium and brads.
6) I cleaned up the PL Premium squeeze out from the previous day. Then I cut panels 5 and 6. I installed panel 5 and then cut the hole for the woofer in panel 6. There's not much room for error; I cut the hole about 1/8" larger (in radius) than the inner diameter of the driver mounting gasket. Even that little bit of space may have been too much; the mounting screws are showing through the sides (shown circled in this photo). I hoped that the mounting blocks would be sufficient to hold the screws and salvage the panel, but I was concerned that there was insufficient support for mounting the woofer.
7) While i was sorting out what to do about panel 6, I ran a test on the woofer (in the soon-to-be replaced panel 6) to ensure that there wasn't any interference between the woofer and panel 6. After that I ran the woofer for 12 hours for burn-in. Here's my setup: I'm using a signal generator to send a 1 Vpp 30 Hz sine wave to an AV amp via a BNC-to-RCA cable. The amp is connected to the woofer with speaker wire. I stripped enough insulation off the speaker wire so that I could connect my DMM. I turned up the volume on the amp until the DMM showed 10Vpp (RMS) at the woofer. I let that run for 12 hours.
After asking a couple of questions on the forum (thanks!), I resigned myself to having to make panel 6 all over again. I wasn't ready to face that, so I moved on to other things.
Because my THTLP will only be 15" wide, I only needed one of each brace. I made them all at once. I also rough cut the remaining panels (panels 6-10). I'll cut them to their final dimensions as I go about installing them .
Current status
I figure that I'm about 1/3 of the way through the build. There's not much to see at this point; the photo shows the THTLP with one side and panels 1-5 installed: Hopefully, I'll get some panels 7 and 8 (and maybe 9 and 10) cut and installed tomorrow. I'm a bit gun-shy about re-cutting panel 6, so that I may do that last (even though it's out of the order of Bill's instructions).
I'd like to give a shout-out to @TomSmit, who has been very helpful. Originally I had planned to have Tom build the THTLPs. But, because I had some time and needed a project, and Tom's schedule was busy, I thought I'd try the build.