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Solid Wood Baffles with MDF/Ply boxes?

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  • Solid Wood Baffles with MDF/Ply boxes?

    Hello,

    What have been peoples experiences/thoughts on combining solid wood baffles with sheet good (MDF or Ply) boxes?

    My 30+ years of woodworking experience tells me that such a large cross grain joint is a bad idea that can only end with the baffle splitting. Yet, I have seen countless examples of such construction posted on the Interwebs.

    I know one thing that would help for sure, and that is "ripping and flipping" the wood, so you end up with a quartersawn baffle (of all the lumber cuts quartersawn has the least amount of movement).

    Are people getting lucky?

    Is it that we live in climate controlled houses where the humidity is fairly constant?

    Has anyone, for example built a pair of speakers in Nevada (low humidity) and then moved to Florida (high humidity)?

    Is it that the modern PVA glues that we use have some "give" to them?

    Are there any guidelines people have used for how wide a solid wood baffle they would on an MDF/ply box?

    Does the thickness of the baffle matter?

    Any failure examples where the baffle did crack?

    What about where the baffles were a glue up of layers of plywood? With this type of baffle, you would think there would still be movement as the layers are not constrained in their "thickness", just in their width and length.

    What are your thoughts?

    Thank you,

    David.





  • #2
    I've done it successfully, but never with wider than a 1x8 baffle. It would be the rare speaker today that had a baffle wider than 7 1/4 inches anyway. As for adhesive, I've used PL Premium polyurethane construction adhesive exclusively for 20 odd years now, and the joints on first speaker I built using it are as solid today as they were when I built it.
    www.billfitzmaurice.com
    www.billfitzmaurice.info/forum

    Comment


    • #3
      Originally posted by billfitzmaurice View Post
      ...It would be the rare speaker today that had a baffle wider than 7 1/4 inches anyway...
      Quick search of popular kits (baffle width):

      Overnight Sensation: 6.0"
      S2000: 6.0"
      C-note: 7.5"
      Tri-trix: 7.5"
      Amiga: 8.0"
      Continuum: 8.0"
      Hitmaker: 8.5"
      Classix II: 8.5"
      Samba: 8.5"
      Solstice: 8.75"
      Kairos: 9"
      Helix Dome: 9.25"

      Comment


      • #4
        Originally posted by a4eaudio View Post

        Quick search of popular kits (baffle width):

        Overnight Sensation: 6.0"
        S2000: 6.0"
        C-note: 7.5"
        Tri-trix: 7.5"
        Amiga: 8.0"
        Continuum: 8.0"
        Hitmaker: 8.5"
        Classix II: 8.5"
        Samba: 8.5"
        Solstice: 8.75"
        Kairos: 9"
        Helix Dome: 9.25"
        He hates it when people call him out, when they let him know. . . .

        Comment


        • #5
          Well, I wasn't trying to "call him out". I am completing a pair of Hitmakers which I knew are wider than that and wondered if they were unusually large so did some Googling. But Bill knows a heck of a lot more than me in general about speakers.

          Comment


          • #6
            I've used solid wood baffles on an Overnight Sensations build. I didn't glue though. I used screws to attach the front baffle. The through-holes are large enough to allow for a little movement of the baffle. Some may quibble about the appearance of screws on the front though.

            Click image for larger version  Name:	os_for_marilyn-41-800px.jpg Views:	0 Size:	139.9 KB ID:	1444898

            If the baffles were larger, I would have used 1/4-20 connector bolts to attach them. I do that often with MDF.

            To ensure that removable baffles don't leak air, I use 1/4" x 1/8" weather-stripping installed in a groove cut around the periphery of the box edge. I use a router plane to do that.

            Click image for larger version  Name:	router_plane_baffle_groove-12-800px.jpg Views:	0 Size:	78.1 KB ID:	1444900
            Last edited by williamrschneider; 06-26-2020, 09:19 AM.
            Bill Schneider
            -+-+-+-+-
            www.afterness.com/audio

            Comment


            • #7
              To the original point, if I was using real wood on a wide baffle speaker I'd certainly consider a flexible adhesive that had a little more finished thickness than say, Titebond. PL Premium might be good, and there are adhesives meant for use in walls for sound damping that might be appropriate. I think I'd also try a grid pattern of adhesive, instead of a solid layer.
              Francis

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              • #8
                +1 on Bill's method. I build a complete MDF box including baffle, rough cut openings slightly wider than driver openings and then attach hardwood baffles with hanger bolts, using gasket around edges. This allows the wood baffle to "float" essentially and have room to move, assuming you drill the mounting holes a bit wider than the hanger bolts.
                Carbon13

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                • #9
                  Another +1 for Bill's method. I did solid poplar on a MDF cabinet screw mounted. They're not that old, but I expect no issues. My next build will be larger with a solid baffle and MDF cabinet, but I'll be screw mounting from the rear for a cleaner look.
                  Electronics engineer, woofer enthusiast, and musician.
                  Wogg Music
                  Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat, SuperNova Minimus

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                  • #10
                    For a visual, check out post 31 here: http://techtalk.parts-express.com/fo...TMM-5-1-Build=
                    Carbon13

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                    • #11
                      william, those look gorgeous -

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                      • #12
                        I'm not so concerned as long as your cabinetry is good. I built this speaker in the mid 2000's with a solid front baffle that's quite wide, complete with thin sections between the woofer and tweeter as well as the edges next to the woofer. It's pretty much purely flat sawn too. It's been through fairly severe temperature swings many times with no issues. It's still as solid as the day I built it. I don't remember what glue I used, but it was a titebond PVA of some sort.

                        The veneer is quilted maple and the front is a 2" slab of highly figured maple I re-sawed to 1" for book matched pairs.

                        Sorry about the indifferent cell phone picture quality. It just happens to be right behind me in the COVID (read: non-optimally placed) home office.
                        Attached Files

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                        • #13
                          Originally posted by Adam_M View Post
                          I'm not so concerned as long as your cabinetry is good. I built this speaker in the mid 2000's with a solid front baffle that's quite wide, complete with thin sections between the woofer and tweeter as well as the edges next to the woofer. It's pretty much purely flat sawn too. It's been through fairly severe temperature swings many times with no issues. It's still as solid as the day I built it. I don't remember what glue I used, but it was a titebond PVA of some sort.

                          The veneer is quilted maple and the front is a 2" slab of highly figured maple I re-sawed to 1" for book matched pairs.

                          Sorry about the indifferent cell phone picture quality. It just happens to be right behind me in the COVID (read: non-optimally placed) home office.
                          Gorgeous. I dare not show that to my wife, she'd ask me to do something similar, and I'm nowhere near good enough.
                          It is estimated that one percent of the general population are psychopaths - New Criminologist: Understanding Psychopaths

                          Comment


                          • #14
                            I'm working on a pair of Continuums in the style of Harbeth BBC monitors. They will have 3/4" cherry baffles and rear panels screwed to softwood cleats in MDF boxes, which mimics the commercial Harbeth construction.

                            I have some solid 3/4" Aspen Mariposas (Quark size) that seem quite stable. I made a pair of Quarks to look like Continuums with solid Maple baffles glued to particle board boxes, OK now for a few years.

                            All fairly small.

                            Comment


                            • #15
                              I have done several pair with wider solid wood baffles, but all have been bolted to the MDF or ply boxes, not glued.
                              Gasket between, which likely allows some movement. No issues with that method...
                              Andy.

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