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  • Baffles first this time

    This is the first time ever that I've made the baffles for a speaker, before the rest of the cabinet.

    Of course, this is the first time I figured I'd trap the front/rear baffles in grooves to maximize rigidity. So the baffles have to be machined before glue-up.

    Cut on my Shapeoko 3 CNC "baffle maker," with 3/16" upcut spiral bit. I leave an onion skin (a very thin bit of material) behind to help hold everything in place until the machining is done. Then I pop them apart with finger pressure and do final clean-up on my router table with a pattern bit.

    Another first is I'll be using zinc-plated tab weld-nuts that are hot-melt-glued to the rear of the baffle, to mount the drivers. My tests of that method have worked better than expected.

    Yet another first for me is how I'll be cutting the 45-degree bevel cuts on the sides of the enclosures. I'll be cutting everything square with 90-degree cuts, and then adding a sacrificial fence and tilting my blade into the fence (I have a right-tilt saw). Finally, a pass through the saw thusly will turn a 90-degree edge into a 45-degree bevel. I tried to find pics of this online, I wasn't able to. I'll take some pics when I'm doing the work.

    I hope to be well on my way to painting the enclosures by the end of the three-day weekend.

  • #2
    Please post pics of the bevel cuts as I've thought of doing this the same way but never found any info to prod me along. Nice little CNC!

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    • #3
      I wish I could have your problems..............you lucky dog.
      Kenny

      http://www.diy-ny.com/
      DIY NY/NJ 2014 https://www.youtube.com/watch?v=FGwA...ature=youtu.be
      Man does not live by measurements alone, a little music helps.

      Comment


      • #4
        Originally posted by scottvalentin View Post
        Please post pics of the bevel cuts as I've thought of doing this the same way but never found any info to prod me along. Nice little CNC!
        I found the article that explains the setup procedure.

        This is what I want to try.

        https://www.canadianwoodworking.com/tools/tilting-right

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        • #5
          Well, the wife started buzzing yesterday about stuff like going on a drive or other ways to spend 3-day holidays that don't end in pairs of subwoofers.

          So I hustled yesterday to get the enclosures finish ready.

          That means I wasn't able to try that other method of beveling the edges of my panels. I did take a look at it but my fence is only about 2" tall and I was concerned about getting a good clamp on the subfence. I had figured I'd use the t-slot in my fence like I normally mount sacrificial fences. But I realized I might not be able to do so using the types of fasteners I have on-hand. I know how to do it, just don't have what I need. I'll have to come back to this. I would someday like a larger CNC, something that can machine 2x4 or even 4x4 panels. I think it would be pretty awesome to cut panels to size, then just zip them through the saw once to put miters on them.

          I'm including some pics to inspire you guys to go out to your shops/garages and do some work.

          First pic is test fitting of an enclosure.

          Second pic is the weld-nuts hot-glued in. I predict this method is going to take-off. The hot-melt glue forms a little sort of mortise that prevents the nut from spinning. You can use a screw threaded into the nut to get it off the baffle, but it will take a decent amount of MDF with it. I've tested this method quite a bit, it is awesome.

          Third pic is of cabinets glued and taped-up. I used fiberglass packing tape. I get it started and just stretch/pull/wrap it around the cabinet in a spiral. I used to have band clamps, I think they got toss accidentally. This method is a good workout, and my wife gets to help hold the cabinet down to the bench so I don't pull it right off. But I need more band clamps for sure.

          Final pic is cabinets this morning after removing all the tape and adding round-overs.

          They're ready for glue-sizing, sanding, and painting.

          I'm going to be using a deck paint carried at Menards. It is said to be 6x thicker than normal paint. I hope to apply it and build a texture with a roller.

          Wish me luck!

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          • #6
            Took a drive to pickup some deck paint yesterday. They had some small samples on display and I found the material a little too soft and easy to pick-off with a fingernail.

            So I ordered some of the Duratex from PE (via Amazon).

            I found a 1-1/4" (I think) foam corner roller at Home Depot. My intention is to thin the Duratex a little, and apply the bulk of it with a 4" foam roller. The foam corner roller will come in handy for rolling the corners created by the inset baffle. Hopefully I'm able to maintain a fairly uniform finish w/o having to resort to spraying. I'd like to keep the texture on the minimal side, I'll do testing on scraps.

            I'm going to have to start deciding what to do about a crossover, too. It would be nice to be able to use a passive so I have maximum flexibility to swap amps down the road.

            Decisions, decisions...

            Edit to add: In researching paint options, I did find a gentleman that mixes PVA glue (he said Titebond 2/3) with tints intended for paint, and he uses THAT as his finish. Had some pretty amazing looking results. After seeing that I found that people have been making paints for quite some time by mixing tins with glue. Something I might try some day.

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            • #7
              I worked on painting them this weekend.

              I had ordered some of the Duratex and experimented a little with application on scraps but was unable to achieve a consistent finish with a foam roller. I likely wasn't applying it heavily enough and it was drying too quickly. But I determined that I'd have difficulty applying it on the recessed baffle in a way I'd be happy with, so I instead decided to go with some General Finishes "lamp black" milk paint. I've used their milk paints before w/ good results.

              My method is to apply 2-3 good coats with a roller (I used a 4" foam roller) to the sides, top, and bottom. The front and back, because they are recessed, get a few coats with a foam brush.

              Because I cannot achieve as nice a finish with the foam brush as I can with the roller, I'll sand the front/back and shoot a final coat w/ an airbrush. I'm up to the point now where I'm ready to do the airbrushing (probably this evening).

              Then I'll let the paint harden for a week or so and I can mount the binding posts and wire things/mount the woofers.

              I still have not determine what I'm doing for crossovers. Because I have spare crossovers from the Canton sub, I'm thinking of actually wiring those temporarily, just to have a listen and see if that satellite choke gets hot.

              I've been toying with the idea of building some simple 6db/octave serial crossovers. Because I'll have a "sub" under each satellite, I can increase the crossover frequency. It would give me a chance to experiment with something new to me.

              The pic makes these look sorta bigger than they are, they're only 1-CF. My wife is kinda looking at me out of the corner of her eye, given me previous corruption of the living room with audio gear. These will fit under the end tables, though. She isn't losing any floor space. I intend to add grills.
              Attached Files

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              • #8
                Originally posted by scottvalentin View Post
                Please post pics of the bevel cuts as I've thought of doing this the same way but never found any info to prod me along. Nice little CNC!
                ​When you do this are there any finished dim. changes when you cut the 45angles from your sq parts? ? for phil

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                • #9
                  Originally posted by Squidspeak View Post

                  ​When you do this are there any finished dim. changes when you cut the 45angles from your sq parts? ? for phil
                  I didn't get to try it this time but it all depends on how accurately you set your fence.

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                  • #10
                    Originally posted by philthien View Post
                    I had ordered some of the Duratex and experimented a little with application on scraps but was unable to achieve a consistent finish with a foam roller. I likely wasn't applying it heavily enough and it was drying too quickly....
                    That was my experience going for a smoother texture with Duratex as well. Glad it's not just me. After some reading, it appears you want the Duratex thinned a little, and you need a second dry roller to go over the surface as you coat it to even the texture. I haven't had a chance to try that myself, but I do intend to re-finish my project before next spring and haven't decided to sand and attempt to get the Duratex right, or sand and paint with another product using the Duratex as a primer on the MDF. The trouble there is I haven't seen a lot of information on what top finishes would be compatible, or if it matters much.
                    Electronics engineer, woofer enthusiast, and musician.
                    Wogg Music

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                    • #11
                      Originally posted by wogg View Post

                      That was my experience going for a smoother texture with Duratex as well. Glad it's not just me. After some reading, it appears you want the Duratex thinned a little, and you need a second dry roller to go over the surface as you coat it to even the texture. I haven't had a chance to try that myself, but I do intend to re-finish my project before next spring and haven't decided to sand and attempt to get the Duratex right, or sand and paint with another product using the Duratex as a primer on the MDF. The trouble there is I haven't seen a lot of information on what top finishes would be compatible, or if it matters much.
                      Well I'm happy to report I biffed the milk paint, too. I tried rolling/brushing it in the recessed baffle area, thinking I'd sand it and spray the final coat on with my larger airbrush. But I got sloppy and applied the milk paint too thick in areas, requiring sanding back.

                      Then I screwed that up, by dry sanding before the paint had hardened enough. Still working on that, I have a technique for fixing it, it is just taking a long time.

                      I'm okay w/ it though, as I'm still trying to learn a decent technique for quickly knocking-out a sub or two, and I'm still learning about how to apply paints. When applied properly, the milk paint really works great and hardens-up nicely (more acrylic than latex, in my non-professional way of looking at things). And with my larger airbrush, it goes on quite quickly, too.

                      The funny thing is, I've done this before with great success, I just apparently forgot the steps from last time. So now I'm documenting how I accomplish things, like how I thin the paint, the pressure I use, etc. Learning is half the battle, remembering is the other half, I guess.

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                      • #12
                        Wow, I wet-sanded (800-grit) the baffles and sprayed a few coats of paint with my airbrush and the baffles have a sort of automobile-quality finish. Not perfect, but close. And if I wanted to make them absolutely perfect, I now know how.

                        That wasn't my intention, I just wanted to clean-up some thicker areas from brushing/rolling. It is a somewhat fortunate mistake as I learned how to achieve that finish, though.

                        So now I'm going to let the paint cure for several days, maybe touch up some areas on the tops/bottoms/sides tonight (those I can roll easily).

                        I consider these prototypes. If I was going to do it again (I guess I am going to do it again), I would assemble the cabinets, apply my glue/water mix primer, sand things with 120 or so, then shoot the fronts/backs with my airbrush. Once that had a few hours to set-up, I'd rolls the tops/bottoms/sides.

                        I built these cabinets with the inset baffle to make adding a grill easier. I'd still like to come up with a design that would allow me to rear-mount these drivers, and have a front-mounted round steel grill. The problem w/ rear-mounting the drivers is the baffle or the rear of the enclosure have to be removable.

                        And I still want to experiment w/ the other method of beveling the MDF, I might do a six-sided cube that way. In that case, maybe I could figure-out a way to make my own decorative ring for the woofer on the CNC.

                        Oh and it is entirely possible these will sound like carp. So I suppose I should get them assembled and do a little testing before I commit to too much redesign. If they sound good, I will make a new pair.

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                        • #13
                          I pulled the trigger on a second SMSL 98E amplifier, and a Rolls SX45 xover. The Rolls SX45 crossover is a 12db/octave adjustable (50-2.5khz) crossover that is small but fairly decently rated. It will serve the purpose at least temporarily and if I'm not satisfied I can change things up.

                          I was going to build passive crossovers but the Rolls is $100 and the amp another $120 or so. If the Rolls is decent, it will save me its cost in crossover components for years to come. And if nothing else, it should give me some ability to audition crossover frequencies for the purposes of designing passives down the road. And it should help quite a bit if these subs are outrageously inefficient.

                          One of the next things I need to do is, seal all the joints on the boxes. I'll have to do so through the woofer cutout. My plan is to stick latex caulk on my finger and smear it into the joints, unless someone has a brilliant alternative to this?

                          Hopefully I'll be testing my setup this weekend. The setup will be messy at first but I should be able to tuck the power supplies for the amps up under the end table, and the crossover can go on the other end table. So hopefully it should all be fairly discreet when I'm done.

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                          • #14
                            Finished-up the two "subs" this evening. Was shopping for ring terminals to connect to the binding posts when I realized I already had some from 3-4 years ago, just had to find them (I did). So wired, stuffed w/ fiberglass, and drivers snugged-up. I sure hope there are no buzzes or anything because it would be a bugger to get the drivers back out.

                            I have no idea how these will sound. I'll be using the Rolls xover to split the signal from my piCoreplayer to two SMSL 98E amps. I think it will be fairly educational to be able to play with the crossover frequency with ease.

                            The suspensions on these woofers seem very tight, I sure hope they aren't horribly inefficient. One of the reviews I read indicated some disappointment on initial listening, but said that after they had run a few hours that they had broken-in and were hitting pretty hard.

                            One of the woofers had a gasket that wasn't properly seated inside the basket properly. At $20 per driver I didn't feel like bothering Parts Express so I shoe-horned it into the position, and hope it stays. Perhaps there is an adhesive I can add, if need be, to keep it from popping back out (if that becomes a problem).

                            I consider these prototypes or a proof of concept. If I like two "subs," one under each full-range driver, I will likely build nicer cabinets. Maybe even move up to 12" drivers. Maybe even make new end tables with integrated 12" drivers, I don't know.

                            Anyway, the xover and 2nd amp come tomorrow, so all I can do now is look at them.
                            Attached Files

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                            • #15
                              Wow, with all the "oops" you mentioned, you would NEVER KNOW IT! Those look great! That's a milk paint finish? I always thought that was more for white-washing type of finish to color but still let the grain show through. I might have to try that, those really look nice. Let us know how they sound after you get a few hours of listening and breaking-in done. For $20, those look like they might be the deal of the year.
                              One question - if you bought the Rolls XO, why not just buy a MiniDSP for slightly more $$$, but with a lot more flexibility?
                              Paul

                              The "SB's" build page
                              http://techtalk.parts-express.com/sh...-4-(pic-heavy)

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