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First speaker build : The Continuum - need help! Several questions

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  • First speaker build : The Continuum - need help! Several questions

    Hi Everyone!

    After years of dreaming about it, I'm finally stepping in to build my first speaker - Jeff Bagby's Continuums! I'm super excited, and equally nervous. First, thanks to Mr. Bagby for designing this speaker and allowing us to build it! I've only ever heard great things about it, though I haven't heard them in person.

    Considering this is my first build, and I have no experience, what should I know before I press the buy button on Meniscus? What other tools (even basics) would I need (assuming I have nothing at all), so I can start planning? I'm planning to use the woodshop at a hackerspace, and they have a CNC. (It's going to be a long, slow learning experience after work and on weekends)

    Here's what I'm thinking so far: wire strippers, wood glue, hot glue gun, masking tape, stuffing (?), some perforated board to mount crossover, actual MDF/plywood (not getting into finishing just yet), screws, screwdrivers, drill, amplifier to test. Am I missing something?

    I was also looking at the possibility of using these https://www.ebay.com/itm/Pair-Speake....c100005.m1851 cabinets, assuming they're a similar size. i can probably request different driver cutout radii. Would that work as well as building my own? Because they do look really good! Would I be able to rear mount the driver on to those? Or do I have to front mount and possibly screw up the sound?

    Ideally I'd love to just use CNC to make flat-pack styles, and assemble using MDF. But I'm not sure how complex the design is on the inside. Maybe I'l find out after purchasing the kit?

    Thanks!



  • #2
    Firstly, welcome to the hobby and good luck with your project.

    I haven't built these, but I've built four pairs of speakers and three pairs of cabinets, so I hope my experience will be at least useful.

    In building any speaker, you really need to follow the designer's plans: the cabinets need to be the same dimensions, port size (if applicable) and volume as the designer has so carefully worked out. There may be some leeway in dimensions, but you should check with the designer if possible on this point. The drivers must also be mounted as per the specification.

    I had a look at the link you provided and the cabinets look nice, but are they the same size as the Continuums: the pdf write up says that the cabinets are slightly larger than those for the :S3/5A. Also, it's hard to tell how well they're made, eg thickness of wood. And if the vendor will cut the drivers holes for you, you might have to send them the drivers so that they accurately can cut the holes and rebates. The $$ will start to mount up.

    You mentioned that you will have access to a CNC machine: MDF is cheap, so why not give that a go? There should be someone to help you.

    In addition to the tools you mentioned, I suggest some clamps, countersink drill bit, different grades of sandpaper, good dust masks - mdf dust is bad news - and a swear jar.

    I'm sure there will be PETT members who have built these speakers and will be able to provide specific advice.

    Geoff

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    • #3
      If you purchase the complete kit from Meniscus it comes with crossover boards, wire, terminals, stuffing, screws, etc. - everything except the tools. Unfortunately, I think those cabinets on eBay are a little too small to work. The volume is a little smaller, but more importantly, I don't the think these slightly larger driver will fit in this baffle. Try your own. You will feel even better when you complete it. And you'll be very proud of your first speaker.
      Click here for Jeff Bagby's Loudspeaker Design Software

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      • #4
        A table saw, plunge router with bits, circle jig, drill and bits and clamps will suffice to produce serviceable cabs for your project. Rear mounting simplifies woofer mounting as the frame is problematic for a simple front flush mount.

        Another company produced finished cabs with the woofer front mounted. IIRC, Mr. Bagby was involved with that project and felt the sound was not compromised. Those cabs are NLA.

        The only tool the "hacker space" might not have is a circle jig that attaches to a plunge router base. The Jasper Jig is ubiquitous but not the only option.

        Finishing is a whole other discussion.

        I made these Bagby Quarks as "Quarktinuums" as a visual goof on Mr Bagby's Continuums. They are Pressure Sensitive Adhesive (peel and stick) maple veneer over particle board with a solid maple baffle. I found this method easiest and quickest to achieve a nice looking cab, much simpler than paint. I have made two other projects in a similar manner, it suits me fine.

        Edit: Painting with a stone texture paint is the easiest finish as it hides mdf joints pretty well. The Continuums deserve a better finish, IMHO.

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        • #5
          Originally posted by audiogeek View Post
          ... I'm planning to use the woodshop at a hackerspace, and they have a CNC. (It's going to be a long, slow learning experience after work and on weekends)
          ... Ideally I'd love to just use CNC to make flat-pack styles, ...
          This sounds like a great plan to learn CNC router operation by making a speaker. I think you want to do it the other way. Bag the CNC unless I'm wrong.

          Think MDF and a table saw to start. Learn to make a 6-sided box with square joints and no leaks, because until you do, you can't build a speaker. Then you're ready to cut circles.

          Once you can make a box, you need a baffle to mount drivers. Jeff did DIYers a favor by rear-mounting the square-framed mid-woofer. Circles are easy by comparison.
          - the tweeter is a 2-stage cut, a large shallow relief cut to flush mount, and a smaller through cut.
          - the mid-woofer is also a 2-stage cut, starting with the through cut, followed by a roundover cut to relieve the front edge.

          I made a pair years ago; they're worth the effort!

          HAve fun,
          Frank

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          • #6
            Solid 3/4" lumber is an option with this size cab. Tyger23 made a nice solid wood pair.

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            • #7
              Salk Sound solid maple.

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              • #8
                A pair of painted mdf Continuums.

                Continuum Speakers Using my Trench Method on the MDF Seams - Techtalk Speaker Building, Audio, Video Discussion Forum

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                • #9
                  Originally posted by Jeff B. View Post
                  If you purchase the complete kit from Meniscus it comes with crossover boards, wire, terminals, stuffing, screws, etc. - everything except the tools. Unfortunately, I think those cabinets on eBay are a little too small to work. The volume is a little smaller, but more importantly, I don't the think these slightly larger driver will fit in this baffle. Try your own. You will feel even better when you complete it. And you'll be very proud of your first speaker.
                  I haven't been visiting for sometimes now, it is good to know you are well. Take Care.

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                  • #10
                    Thanks for all the help so far - this forum is fantastic!!

                    Geoff, thanks for the tool list and tip on MDF - hadn't thought about the dust.

                    Jeff, that is great advise. I'll have to resist my temptation for instant gratification, and build my own learning the hard way - should be much more fun!

                    Frank, that's helpful - I do have good CAD experience and I've had stuff made on CNC before, this would just be a different machine so it'll be new for me. I might actually try two styles at the same time, one of each (handmade and CNC), and build the one that works better. (Travel costs + time are way more for me than material costs, so building two makes sense)

                    djg, thanks! That lumber looks great, if it's not too hard to work with I am tempted! Since it doesn't contain glue I might even be able to laser cut this.




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                    • #11
                      I bought the kit sometime back, but didn't receive the crossover board. It'd definitely make my life easier ... I should call meniscus then.

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                      • #12
                        You don't get crossover boards... unless that's a relatively recent add. I bought 2 kits at different times and neither had boards.

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                        • #13
                          The Continuums in translam cabinets, done! And the verdict is they sound...


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                          • #14
                            Kidding. The hard work begins now! After some thought, and checking out the CNC (4-axis, so can do linear cuts at different depths), I decided to go Translam. So expect a few dozen questions coming in! Is it the most efficient? No, but I can probably manage in 2 5x5 BB plys. My thought was simple : the sound design's been given much love, so I can at least put some effort into the look and build. Personally I am not a fan of box-speaker aesthetic, and I love some translam builds I've seen (Magico mini inspiration is clear). I plan to use a blue dye and sealant to get a nice finish on the sides. I have ~1.5 inch thick walls throughout, with 2 bracing layers, so I'm hoping to get low resonance. Plus, I don't have to touch a saw! (I'm pretty confident of messing up any hand-operated cuts) I am fine with a lot of sanding. I'll allow for some alignment holes running vertically, so I can stack on a dowel/metal rod. Hopefully this will eliminate errors from my end.

                            I've used the same baffle dimensions as original, and roughly the same internal volume (0.31 cu.ft, but this doesn't accomodate for volume of crossover units and driver bodies.

                            Now for the questions :

                            1. Material and finish of the black pieces : I like 2-tone finishes. I have some flexibility on the top piece, back piece, bottom piece, and baffle. I want them to be built of the same material ideally, something that machines well and hopefully has a decent finish just by sanding. I've heard of Corian, any other recommendations?

                            2. Anything I should be aware of before getting into translam? I'll come up with questions on the best glue to use etc later, but does the build plan look ok for now?

                            3. Bracing/cabinet suggestions to optimize sound even more?

                            4. Aesthetic suggestions?

                            The kit has arrived and I'm super psyched.

                            Thanks!

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                            • #15
                              Jeff B.

                              Hi Jeff!

                              After I posted this plan over at Reddit I have found a few people interested in doing a group "buy" of sorts, for the CNC'd cut parts. It would help reduce costs to get them machined together.

                              Before committing to anything or asking more people, I wanted to check with you as they are your design, of course. I'm not doing anything with the kit directly, but I've modeled the cabinet to fit the approximate volume and baffle width, as I've seen them being public. The others will be responsible for purchasing the kit from Meniscus. I'll leave the baffle optional for them to build so they can use it with other designs if they wish.

                              Please let me know if you're cool with it. I'm not trying to make profit off it, just cut costs

                              Best,
                              Akhil

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