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Bantams MTM Underway...

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  • #31
    Wow, that looks like it was pretty hairy to do by hand. I'm betting the Walnut baffles will look fantastic after they are finished!
    My "No-Name" CC Speaker
    Kerry's "Silverbacks"
    Ben's Synchaeta's for Mom
    The Archers
    Rick's "db" Desktop CBT Arrays
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    • #32
      Tom those rear mounts are def the way to go, so elegant and effective. If you need to do that again on such thick stock you might consider splitting the 7/8 board on the bandsaw into like a 3/8ths thickness cut for the front of the baffle with the roundovers for the drivers, then you can cut the back 1/2" on a scroll or jigsaw for the back part of the baffle, glue them back together and they will look just like yours but be easier. I did that with these, mahogany cut for the face laminated to MDF that was cut out oversize for speaker frames using Davis 16s with the odd frames. But yours are gorgeous.
      When you run make sure you run,
      to something not away from, cause lies don't need an aeroplane to chase you anywhere.

      Comment


      • #33
        Originally posted by Tijmen View Post
        Wow, rear mounting the drivers really makes the baffle look so clean! I think it was worth the effort. Such a shame that these dayton audio drivers are quite a bit more expensive here in Europe.
        Thanks, that's why I did it, for the clean look, but it was just entirely too much work..... on the other hand......

        Originally posted by Kevin K. View Post
        Wow, that looks like it was pretty hairy to do by hand. I'm betting the Walnut baffles will look fantastic after they are finished!
        ...... if I had used a CNC machine to do these baffles, I bet things would have been gone much smoother. With the precision a CNC affords I could even see leaving four blobs of wood there which could later be grooved out with a dremel cut-off wheel for the driver flanges to "Turn into" like screwing in a screw. Then just a few screws to keep things in place would be all you need.

        Really though, this is a crazy amount of work just to get this to fit the space constraints. I went a bit too far I think trying to get everything into the sub-3 Liter space available. The 'public' Bantam MTM's will be an inch or so taller and a few inches wider and not have all these 'too close for comfort' tolerances to worry about.

        I used a 1/2" straight cut bit in the big router to get that material out. Drew the profile of the driver flange on the back and freehanded it in two passes at two depths. Can't see from the pics, but I got most of the dark burn marks out by sanding with medium coarse paper. Just have to wait for the tiny #2 x 1/4" screws to come in so I can get these drivers mounted. I've never need a set of jewelers screwdrivers to put together a speaker before!

        TomZ
        *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
        *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

        *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

        Comment


        • #34
          Originally posted by biff View Post
          Tom those rear mounts are def the way to go, so elegant and effective. If you need to do that again on such thick stock you might consider splitting the 7/8 board on the bandsaw into like a 3/8ths thickness cut for the front of the baffle with the roundovers for the drivers, then you can cut the back 1/2" on a scroll or jigsaw for the back part of the baffle, glue them back together and they will look just like yours but be easier. I did that with these, mahogany cut for the face laminated to MDF that was cut out oversize for speaker frames using Davis 16s with the odd frames. But yours are gorgeous.
          Wow, those speakers are just amazing looking... super nice!

          Took me two reads to understand what you were saying but I get it now. I have a band saw, I guess I could have pulled that off! Plus I could have maybe included some sort of blind nut to mount the drivers with on the inner part of the baffle, or some kind of mounting system. It gets complicated the smaller you go.

          I think I remember you working on those speakers awhile back, you used the large radius roundover pieces from MDF from that online supplier, right? I've used them before as well, possibly at your recommendation? Brain is fuzzy these days. Anyway, beautiful speakers, they are works of art.

          TomZ
          *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
          *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

          *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

          Comment


          • #35
            Some people have had ingenious ways to mount a rear-speaker setup. Mark65 used a ring that came a bit proud of the inside wall, and used a clamped sort on the thicker baffle areas to secure the ring.
            I don't recall whom, but others have used a set of dowels/blocks on the mounting points in the same manner. Others have bolted through the baffles (Paul Carmody?) like in Jeff's Continuums. I think you used some kind of split washer at some point to keep a driver in the mount. There are many ways to do it.

            Later,
            Wolf
            "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
            "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
            "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
            "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

            *InDIYana event website*

            Photobucket pages:
            http://photobucket.com/Wolf-Speakers_and_more

            My blog/writeups/thoughts here at PE:
            http://techtalk.parts-express.com/blog.php?u=4102

            Comment


            • #36
              Thanks Tom for the kind words - those do use the 3" radius roundovers for the corners, the compound angle at the top was so much fun, lol. In this case those Davis drivers frames are like Focal flat side rounded corners, so the back part of the baffles were cut flush for all three drivers sides, drivers mounted to the front mahogany, then that piece screwed and glued to the cab. I have found the split baffle makes the working much easier, for me anyhow.
              When you run make sure you run,
              to something not away from, cause lies don't need an aeroplane to chase you anywhere.

              Comment


              • #37
                Tom, this is what I did with my rear mounted ND105-4 in my AP3 build. The TC9 is what's shown in the second picture but the ND105 wored the same way. I just used wood screws to compress the plate to the baffle.with a little bit of gasket material.



                -Kerry

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                • #38
                  Kerry,
                  Your pic startled me a bit when I saw it, the first one with the words 'dead inside' written on it... I thought for a moment it was my pic and I KNOW I didn't write that on any of my scraps. I like your solution too. That's really going the extra mile; It really takes a BUNCH more work to get these little last touches finished up. I guess it's what separates the men from the men with a lot of free time. I'm not sure I could have made that method work in this instance, it is really tight in there. I had to do some surgery on the ND91's to get them in there.

                  I used those little screws #2 x 1/4" stainless, two per corner to get these mounted. Seems to be sturdy enough. The walnut is hard enough to give decent bite with the little bit of thread seated in the wood. Never would work for MDF.




                  Here's a comparison between the little screws I'm using to hold the ND91's compared to our standard #6 at 3/4" long... Tiny buggers, no?



                  They're starting to look like speakers almost:



                  Binding post ready to go:



                  More interference issues. Mounting screws for the Peerless side facing Passive Radiators:



                  The solution:



                  It seemed like a better alternative than shortening the screws.

                  Ready for poly:



                  I have the first coat of poly on the cabinet and bases, just the veneer, not the hardwood bits. I wanted to get Eileen's input with the samples I did on how dark to go with the walnut bits. I did several samples with darker/lighter stain and straight poly.

                  Turns out she likes the look of the poly the best, which makes it easier... I like that better too. Too dark and you loose the light-shifting effect of the quilted grain in that walnut, I'd like to keep that if possible.

                  Next weekend I hope to have these together and ready for measurements.

                  Tom tired, must sleep.

                  TomZ
                  *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                  *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                  *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

                  Comment


                  • #39
                    Looks great Tom. I had a thought about the PR tuning. Could you try tuning one PR to a lower point by adding weight? I had a pair of Polk Audio RTA 11T's that was a MTM floor stander with two PR's tuned differently. That may allow for some lower extension. Just thinking out loud.

                    Scott

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                    • #40
                      Originally posted by MLS View Post
                      Looks great Tom. I had a thought about the PR tuning. Could you try tuning one PR to a lower point by adding weight? I had a pair of Polk Audio RTA 11T's that was a MTM floor stander with two PR's tuned differently. That may allow for some lower extension. Just thinking out loud.

                      Scott
                      I suppose that is possible, though adding weight to these pr's would mean adhesive as there is no threaded rod or disc. Plus I use bass box pro for my box modeling, and with that program both pr's have to be the same. These nd91's can only reach so low. Still, I suspect more extension than the original Bantams. Interesting idea, but without the ability to easily add weight, it's hard to test it out.
                      TomZ
                      *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                      *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                      *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

                      Comment


                      • #41
                        Nope the tunings will join to one net tuning, even if they are different.

                        Later,
                        Wolf
                        "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                        "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                        "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                        "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                        *InDIYana event website*

                        Photobucket pages:
                        http://photobucket.com/Wolf-Speakers_and_more

                        My blog/writeups/thoughts here at PE:
                        http://techtalk.parts-express.com/blog.php?u=4102

                        Comment


                        • #42
                          Scott,
                          Is it possible that the two woofers in the MTM each had their own airspace and passive radiator, each tuned to a different frequency?

                          TomZ
                          *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                          *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                          *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

                          Comment


                          • #43
                            That would do it.
                            Wolf
                            "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                            "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                            "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                            "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                            *InDIYana event website*

                            Photobucket pages:
                            http://photobucket.com/Wolf-Speakers_and_more

                            My blog/writeups/thoughts here at PE:
                            http://techtalk.parts-express.com/blog.php?u=4102

                            Comment


                            • #44
                              Things are getting shiny...





                              About 5 coats of rub-on poly so far, probably another 3-4 to go. I always ask my wife what she likes regarding veneer, finishes, and color, and she said no darker on the cabinets, I had planned on toning them down a bit. The baffles are darkening up on their own with just the poly.

                              Assembly followed by measurements this weekend Lord willing. I'm really excited to hear these things start making noise. I'm hoping the extra bass over the Bantams is enough to allow these to mimic a decent 5-6" two-way. Yeah, I know that's pushing it... but I'm hopeful!

                              TomZ
                              *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                              *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                              *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

                              Comment


                              • #45
                                Originally posted by tomzarbo View Post
                                Scott,
                                Is it possible that the two woofers in the MTM each had their own airspace and passive radiator, each tuned to a different frequency?

                                TomZ
                                No. They were all in the same airspace.

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