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updated 03_september_07 Bug 1: Piece 6 is 1/4" too long and will need to be shortened. Bug 2: piece 12 is a tight fit. A bit of sanding or a utility knife to increase the length of the rebate sorts this one out. Our biggest concern with this batch was whether our desicion to rebate both panels was a good one. Already from the feedback of the 1st 2 builds we were right to be concerned. One needs to be very careful to get the panels perpendicular and still some fiddling may be required to fit the 2nd side. (future flat-paks will forgo the rebate on the 2nd side as per Phil's suggestion). Phil: I think I found the best way to build using the dado sides: Install the very center section first then use the top side and mate it up over the center section. Do not use glue for the top side. After the glue dries remove the top side. Then add more of the parts around the center. But as they are added use the top side to help make sure everything is in alignment. This will take more time to build since you must wait for the glue to dry on each section. If one gets the center section right, the rest will fit very nicely. The center needs to be dry before you remove the top side! Ken: I'm inclined to make some comments as I get closer to gluing the second sides over the interior horn labyrinth. The final sides have been quite a chore to match up, side to side, incidentally. Besides some utility knife work with a straight edge to relieve some rebates, I also did some chop-saw trimming of certain parts, with a very expensive compound miter blade that most folks wouldn't have. Fortunately, my chop saw makes it across the width of the inside parts for occasional trimming. I believe the rebates require more tolerance on the final side so to be glued, especially with regards to the inside labyrinth parts. That said, I've done much shaving of parts and utility knife/scraper adjustments of those rebates on the final sides and am now close to getting a both cabinets completed. The joining of the parts has been with very minimal clamps, incidentally. |
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Dennis: 1) I am not a total novice, but an intermediate level woodwoorker with reasonable experience with both hand and power tools. 2) I built the Frugals using a hybrid of Phil's and Chris' methods. I first installed all interior labyrinth pieces at once (did not use the 2nd side as guide), but then had to WIDEN the 2nd side dados 2mm with utility knife to make the 2nd side drop on down. (What a pain in the ass...more on this later!) 3) I then installed pcs 6 + 7, using 2nd side as alignment guide. 4) Piece #3 went in, I needed to sand the dado in #2 side to get it to align (60 grit). 5) Piece #4 (bottom) then #2 (front) then # 5 (top) went in...each being done separately until glue dried. The 2nd side was used for alignment on these 3 pieces . Now...my problems and recommendations: 1) The dados on 2nd side should be KEPT...reason is, the internal pieces will never be exactly the same width and to think one will get 100% perfect contact with 2nd side is unrealistic. By having dados, a "tunnel" is formed that "cups" the internal pieces and allows glue to pool up and grab the pieces, even if not making 100% contact. Plus, that dados act as self-alignment jig when building. 2) The dados on the 2nd side need to be WIDENED by 2 or 3 mm, however, NOT ALL of them. Leave the dados for pieces #3, 6, 7, 4, 2 and 5 as a tight fit...as these are the critical pieces for overall side-to-side alignment. |
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3) You need to very carefully control the depth of the dados...they need to be totally uniform. One one speaker only, my center labyrinth ended up a few degrees "cock-eyed" (not perpendicular to the side) because of this problem. See the picture...pieces # 6 and 7 were subsequently not totally perpendicular to the labyrinth...about 1.5 mm misalignment (gap) at one end (will this effect the sound????). Also, I had to do a fair bit of orbital sander work to make all the inside pieces the same width...so the 2nd side would fit flat without "see-sawing" on the wider pieces. |
| 4) I feel that more care needs to
be applied, regarding the cosmetic quality of the side pieces. Being baltic, I was
assuming that I could simply sand and stain if I wanted to. However, both of my side
pieces contained big "eye" knots from ply manufacture, a few serious gouges
in the front edge (of all places!) from a router bit. Also, one side piece had the
outer ply stripped off over a 3 " long section. Saw cuts had a lot of deep splinters
as well. Rougher than I had expected. I know this is a Beta kit, but I must now resort to build up/filling in these areas, and this together with the "eye" knots...make staining an impossibility. I now must veneer (!) or apply a thick paint finish, such as a flock to hide the imperfections. A bit more involved than I had hoped for. I will be travelling for a few weeks and so will not be able to fire them up until I return, dang it. When I do, will be glad to give my listening impressions vis-a-vis my Fostex FE-103E in small vented cabinets. Probably will be ordering a supra baffle as well, as I really hate to have an upper bass dip due to baffle step. Of course...will listen to the "stock" kit first and do these improvements incrementally. It has been frustrating at times, but still fun!!! Bravo...! Regards, Dennis San Diego, CA Martin: I am on vacation these past two weeks and have spent some time building the Frugal-horn. I made some notes as I went along and have included them below. I built the first enclosure following the assembly order shown in the pictures on your website. I must have not gotten every piece perfectly perpendicular or square. At two locations I ended up with a small tapered gap that I filled with caulk, no big problem. Closing the enclosure by adding the second side was not even close to working without some rework (see below). When I started the second enclosure I decided to change the order of assembly to try and use mating pieces as guides to get the enclosure trued up better. This worked very well so I wanted to pass on my lessons learned. The order in which I built the second enclosure is provided below. 1. I started by installing parts 6a and 6b (after cutting 6b back 1/4 inch). I glued the two 6's together and glued them into their slot using part 2 and the driver mounting plate as guides to get them straight and perpendicular. Note part 2 and the driver mounting plate were not glued at this time. Then I glued in part 7 and used it to set the depth in the slot of the 6's. After sliding around and lining up the 6's and piece 7, I clamped everything together and removed part 2 and the driver mounting plate. The end result was square and perpendicular positions for the 6's and part 7. It took an hour or so for the glue to dry. 2. I then added parts 9a, 9b, and 10. I clamped these pieces and waited the hour required for the glue to set. Then to complete the "trapezoidal box" I added the small piece (forgot to write down the part number) at the bottom pushing and pulling parts 7 and 10 to align everything flush. Glue, clamp, and wait an hour. 3. Using the 6's as a guide, I added the front (part 2) and used the bottom (part 4) to square up the front. Part 7, the diagonal, was added and used to square up all three parts. Glue, clamp, and wait an hour for everything to dry. 4. Using the driver mounting plate, I positioned and added the top (part 5) and then the back (part 14). Glue, square, and clamp followed by an hour wait for the glue to dry. Remember to remove the driver mounting plate before ant glue leakage sets saving installation for later, it could be glued in this step but I am not sure if I want it permanently installed or removable. The fit up is good and snug so I can glue it in later. 5. Final step was to add parts 12 and 13 using clamps to square and tighten them with respect to the back (part 14). This took about 12 hours over one day. Most of the time was spent waiting for the glue to dry. This was a very easy build sequence and the end result was no gaps and all of the pieces fitting together nicely, I tried putting the last side on the second enclosure and it almost dropped into place, with some mild sanding in one or two spots I believe it would slide on fairly easily. My plan is to widen the slots in the final two sides. I am going to use my router and a guide to shave off about 1/8 of an inch on each side of the slots. I am thinking about making my set with removable sides, using soft foam weather-strip, so I can experiment with adding stuffing, small obstructions, and putting the mic through the side at different axial locations. I would also like to try a couple of different drivers. I really like the slotted sides for assembly. My recommendation would be to leave one side tight to assemble the horn's path and widen the second side's slots. This would allow assembling the horn and then flipping and lowering it onto the second side, the wider slots on the second side could have a generous supply of glue that would fill the slop in the slot assuring a completely sealed path. I have always worried about leaks around blind butt joints internal to a cabinet. Gravity would pool the glue in the slot at the joints. Hope that is of some use, Martin |
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