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The Experiments -- Small Desktop Speaker

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  • The Experiments -- Small Desktop Speaker

    After using X-over Pro for years now, I was finally getting myself up the courage to delve into the PCD/WinPCD programs. I've tinkered with them for awhile, Omnimic too, but it's finally time to get a little more serious about it I think.... Then XSim comes along... I think I may lick this crossovering thing yet!

    I decided to build a small two-way speaker to try to learn measuring and crossover sims on. I made the cabinet a few days ago and spent today machining the baffle which is solid 3/4" maple. The remainder of the cabinet is 1/2" MDF. These are small.



    8.5" tall, 4.5" wide, 6.5" deep. The front slope is about 83 degrees, and the top/front angle is 90 degrees. Kind of the same shape as my "Beast" subwoofer from several years ago. I like the shape, and to be honest... these were pretty much inspired by Tom Bond's small desktop build he showed at the MWAF this year; sorry, my brain can't remember the name of them, but they were super-cool looking. I'm going for a similar aesthetic with these.



    They will be vented with a 1" by about 7-8" port, depending on how things turn out. Approx. .058 cu. ft. The port will face down, and the cabinet will be suspended by small spikes that were on buyout several years ago. They will place the box approx 1" off the surface for good breathing room, and port velocity is pretty low with a 1" port.



    My first screw-on baffle. Yes, I freehanded the recessed opening for the woofer. It's harder to do than it looks, and judging from the pic, it's pretty hard to do!





    Man, these things take awhile to machine! Maple machines good, though. It's a lot of work for such a small little bugger, but it's good therapy I guess. I wanted to make the front easily removable since these will be like the name says, an experiment for me. The through-holes in the baffle are much larger than the screws, and the head is flat and large to allow for movement of the baffle as it is real wood. I think that's the right way to handle that?

    The drivers are the Aura NS3's, the 8 ohm version. I wanted these to be playable on any little amp thingy that may not like 4 ohm speakers. The tweeter is a Vifa buyout from a few years ago at the tent sale, they were $10/ea, I took four just for fun. There is about a smidge over 1/16" of an inch of mounting surface, on the front of the tweeter so I had to be a little more careful than I normally am with that one.



    The F3 in this box should be around 60-65 Hz or so, and should have some useable bass down to 50 Hz or thereabouts. Decent for small little test speaker.

    By the way, I'm going with Bubinga waterfall veneer for the top, sides and probably back; this stuff: http://www.woodcraft.com/Product/200...q-ft-pack.aspx

    I'm in no hurry to veneer though. I'll let these live in raw MDF for several months to let the stuff equalize before I finish them.

    As far as crossovers and the like... I have no idea! Once I get things buttoned down and airtight, I'll take measurements and then see what happens. School will be back in session in a few weeks, so progress will probably be slow as I will be learning as I go.

    So that's it for now. I'll post more when I get some more done!

    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

  • #2
    Re: The Experiments -- Small Desktop Speaker

    Looks good Tom! Be prepared that your crossover may need to be external. Trying to squeeze them in there isnt going to be easy.
    https://www.facebook.com/Mosaic-Audi...7373763888294/

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    • #3
      Re: The Experiments -- Small Desktop Speaker

      Good work, Tom! I hope they sound as good as they look. Howard

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      • #4
        Re: The Experiments -- Small Desktop Speaker

        Originally posted by isaeagle4031 View Post
        Looks good Tom! Be prepared that your crossover may need to be external. Trying to squeeze them in there isnt going to be easy.
        Yes, I didn't really even leave room for a terminal cup since the port is so far to the rear. I'm most likely going to need to do a crossover outside the box so to speak and biwire. A couple of decent sized caps and a coil or two will take up half the volume. Hey, maybe I should use air-core inductors; that'll save some air space

        Originally posted by howard View Post
        Good work, Tom! I hope they sound as good as they look. Howard
        Thanks Howard. I'm still trying to learn this stuff, but I'm not giving up!

        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


        • #5
          Re: The Experiments -- Small Desktop Speaker

          Super cute! Too bad the tweeter is NLA - I've got some NS3s looking for a home in a project like that.
          It's so small, even the 1x1 mounting blocks for the baffle look huge.

          I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
          "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

          High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
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          • #6
            Re: The Experiments -- Small Desktop Speaker

            Tom, nice.

            Don the XT25SC90 will be very close.
            John H

            Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

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            • #7
              Re: The Experiments -- Small Desktop Speaker

              Nice work Tom! Looking really good, and the veneer should look awesome with those. You might be able to get the crossover inside if you split it in two and mount the woofer xover on one side wall and the tweeter network on the other. I had barely enough room to get the xover in mine without splitting it. Can't wait to see the finished product.
              "If you cannot find the truth right where you are, where else do you expect to find it? - Dogen

              "Why are you wearing that stupid human suit" - Frank

              "We spread the time as we can, but in the end the world takes it all back" - Roland

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              • #8
                Re: The Experiments -- Small Desktop Speaker

                Cool. I love tiny builds like this. Every mm matters with such a tiny setup.

                How are you going to secure the drivers to the baffle? I caused headaches for myself trying to rear-mount with tiny screws (they poked through the baffle roundover) so I'm guessing some sort of glue is the right way to go?

                I gotta get me some of those awesome giant-head screws.

                Looking forward to following the project. Good luck with the XO

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                • #9
                  Re: The Experiments -- Small Desktop Speaker

                  Originally posted by donradick View Post
                  Super cute! Too bad the tweeter is NLA - I've got some NS3s looking for a home in a project like that.
                  It's so small, even the 1x1 mounting blocks for the baffle look huge.
                  I think I'll shave the mounting blocks down a considerable amount after I run the screws in and out a few times, That wood is just cut up 2x4 material, so probably Fir, I'll need to be careful... they do look huge in there. I used some bees wax to help the screws go in easier.

                  Originally posted by jhollander View Post
                  Tom, nice.

                  Don the XT25SC90 will be very close.
                  Thanks. That tweeter does look exactly like it from the front, and even pretty close from the rear with a very similar heat-sink type of thing on the back. I guarantee that mine is harder to mount, though!

                  Originally posted by tombond View Post
                  Nice work Tom! Looking really good, and the veneer should look awesome with those. You might be able to get the crossover inside if you split it in two and mount the woofer xover on one side wall and the tweeter network on the other. I had barely enough room to get the xover in mine without splitting it. Can't wait to see the finished product.
                  Thanks Tom, like I said, they are just an "Other-Tomly" version of your creation. I would have no trouble fitting the crossover if didn't port these, but the F3 would be in the 120-130 Hz range; I'd rather have these be a little more full-range since the woofer is willing. I may be able to shorten the port a few inches depending on how the air under the cabinet couples with the port. I'll have to experiment a bit with that.

                  Originally posted by lowpolyjoe View Post
                  Cool. I love tiny builds like this. Every mm matters with such a tiny setup.

                  How are you going to secure the drivers to the baffle? I caused headaches for myself trying to rear-mount with tiny screws (they poked through the baffle roundover) so I'm guessing some sort of glue is the right way to go?

                  I gotta get me some of those awesome giant-head screws.

                  Looking forward to following the project. Good luck with the XO
                  How am I going to secure the drivers to the baffle?.... Well Joe, I'm going to use duct tape, of course!

                  Good question. I'm planning to make a few pieces of bent steel or alum. bar-stock to screw into the baffle which will "press" on the rear tab/hole areas of the woofers. I should have room for this if I'm careful.

                  The tweeter will likely be a band of alum. to press-hold the rear to the baffle. I also want to use a little caulk to shoot in between the tweeter body and the baffle to help keep it centered in the hole and help seal it up. It wouldn't take much for the outer ring to touch part of the baffle, I'm sure that would cause some issues sound-wise.
                  *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

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                  • #10
                    Re: The Experiments -- Small Desktop Speaker

                    I've done a couple of pair with removable hardwood baffles and rear mounted drivers. Here is one example of how I physically secured the tweeter:



                    Craig

                    The lowest possible F3 box alignment is not always the best alignment.

                    Designing and building speaker projects are like playing with adult Lego Blocks for me.

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                    • #11
                      Re: The Experiments -- Small Desktop Speaker

                      Tom, I love the baffles.
                      Click here for Jeff Bagby's Loudspeaker Design Software

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                      • #12
                        Re: The Experiments -- Small Desktop Speaker

                        Originally posted by PWR RYD View Post
                        I've done a couple of pair with removable hardwood baffles and rear mounted drivers. Here is one example of how I physically secured the tweeter:



                        Craig, thanks for that idea... consider it stolen! That looks like the same tweeter as well? Or pretty close to it.
                        I'm laughing at the "A" and "B" labeling on your baffles. I do that because one side is always a smidge off from the other no matter how hard I try to make them the same. The world is imperfect, and my woodshop even more so!

                        Originally posted by Jeff B. View Post
                        Tom, I love the baffles.
                        Thanks Jeff. I forgot how nice it is to work with a hard type of wood that doesn't smell like MDF, Doesn't splinter apart on every edge, and where mistakes can be magically sanded out! Makes me want to use real wood materials a little more often.



                        They almost look like a "Mini-Me" version of your Continuums if you squint.

                        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


                        • #13
                          Re: The Experiments -- Small Desktop Speaker

                          I think I figured out how to hold the woofer in place:



                          I cut a washer with clippers and twisted it around half way or so,

                          Then I center punched a dimple near the end of it so the 1/8" drill bit doesn't walk off the washer when I'm drilling through,

                          I pre-drilled a hole in the baffle just deep enough for the small sheet-metal screw. I taped my depth on the bit so I wouldn't drill through the baffle.

                          Bend to tweak as necessary to provide good pressure.

                          (The test "demo" washers were of a smaller diameter, the ones I used were larger and had more meat around the 1/8" hole.)

                          Seems like it will hold very well. Unlike most "figure it out" type of things that was surprisingly easy!

                          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

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                          • #14
                            Re: The Experiments -- Small Desktop Speaker

                            Nice!



                            regards,
                            asmd.

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                            • #15
                              Re: The Experiments -- Small Desktop Speaker

                              Similar to Craig this was my mounting
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                              John H

                              Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

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