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ION Micro Full Range Surrounds - Dayton Audio

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  • ION Micro Full Range Surrounds - Dayton Audio

    Having just finished my Accuton bookshelf speakers, I was looking for a new project. Having expended most of my budget on those, I wanted to find a very budget friendly speaker project. I decided the next step was home theater. We don't have room currently for a proper full setup so these speakers will be used for 2.1 channel home theater until we move. I plan to build 2-way fronts, a sub, and MTM center to accompany these speakers. While they will serve 2.1 duty for now, they will eventually be used for rear surrounds due to the limitations of the full range small box design. The drivers will be the Dayton Audio RS100*4 4" Reference Full*Range Driver 4 Ohm. These will be driven with a 5.1 receiver. Full range was chosen to keep cost down (one less driver and no crossover parts) and to allow the boxes to be very small for surrounds.

    We are somewhat worn out with the challenged of translam design, so decided to go with a more traditional box. Since we have a laser cutter and CNC available, I was not going to be satisfied with a plain box with rounded corners. This design can definitely be made without CNC assistance, but the CNC helped save us the effort of creating jigs and templates.Even simple cuts will be made on the CNC just to simplify the tools and process. I decided that a 3D-carved baffle and rotational feet would give the impression of more complexity but still only requires 90 degree joints. The initial mock-up reminded me of a TIE fighter, which is why I am naming the system the IONs (TIE = Twin ION Engine).





    Next we had a short part of an afternoon so I decided to quickly design some magnetic grills to eventually go on the speakers to protect them from incidental contact. Where we live now, these will be in a high-activity area. The grilles were designed using 1/8" walnut laser cut in a hexagon design (somewhat similar to the TIE fighter windscreen). To mount the magnets and space the walnut from the actual driver, 1/4" acrylic was laser cut and glued to the walnut. Three magnets were mounted in the acrylic to match the spacing of the screwheads so it can magnetically mount to the screws. These took maybe an hour or two from first conception to finished product.



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    Fast forward a week and we finally had time to CNC cut the rest of the parts. We began with the baffles, which were machined from 3/4" solid maple.







    We elected to use a straight cut bit to save tool changes and didn't use a particularly small stepover. For those unfamiliar with CNC, this means that the carved baffle has a stairstep look. We wanted the edges to be smooth, so I used a finishing sander to remove the stairsteps and leave the angles. This manual sanding process makes the final baffles less precise, but helped make the process faster. Here is a side-by side to show what the sanding did.



    While sanding, we sent the CNC to work on the 1/2" baltic birch ply sides. I forgot to take photos of the feet/wings being machined, but they were cut from 1/2" solid walnut. It took us about 3 hours to get all of our parts machined and sanded.



    Now we have all of the machined parts we need to assemble the speakers. We gathered the machined parts with the hardware, and made the short wire harnesses needed to connect the drivers to the binding posts. Also not shown, we quickly cut some foam-rubber washers on the laser. These washers will go between the wings and body to keep the body from rotating without having to use too much clamping force on the screw.





    Getting this far, I couldn't resist quickly assembling them to test out these drivers. We just quickly taped the sides together using blue tape, and installed the binding posts and driver. We did our best to seal the cracks with the tape, but obviously painters tape doesn't make for a very rigid box. We joked that its a feature since the whole box feels like a passive radiator. Assembly took maybe 20 minutes. You can see how the wings will mount with machine screws, into threaded inserts on the sides of the boxes. When done, the body will be able to rotate some to suit the location they are placed. The body doesn't touch the ground, only the wings. I tried to design the pivot point to be at a location where the front-weighting of the driver and the back weighting of the speaker wire would balance well. The plywood will be glued together, sealed, and then covered in a metallic dark blue vinyl. This was chosen to allow the build to stay cheap, fairly durable, and easy to assemble. The maple and walnut will be finished to a glossy finish.







    Here you can see the quick and dirty test setup. We hooked them up to a parasound stereo amp and tested out tracks we know well from Tidal. They don't sound how they will at the end due to the total lack of rigidity in the box, but our initial impressions are that these full range drivers sound good in the mid range, harsh in the highs with poor dispersion, and lacking bass. The bass is to be expected for such a small driver in a small non-ported cabinet and is not a problem since the sub should take care of what is lacking. In the sweet spot, these have pretty good imaging, but it is lost when you go only a few degrees off axis. When movie material is played we found that the dialogue was a little hard to isolate when there was also bass being played. We found that they sounded much better when DSPed to bump up 250-500hz and to bump up 3k+. The 250-500hz was especially noticeable in male vocals. Without the DSP male voices sounded thin. We are hoping that when the box is more rigid and a sub is mixed in, this won't be as much of a problem. Sound effects like lightsabers and instruments like horns and saxophones sounded particularly good with these drivers.



    Next step is to work on actual assembly. Including the test-assembly and an hour of listening, we are about 7-8 hours in (not including 3d design time, which is maybe another hour or two). I expect that the whole build will be completed in about 15 hours total. Happy to answer questions. I will continue to update as I finish these up. As I finish these I am also going to be researching subwoofer design since I am planning to build an 8"-10" powered sub in the same style to accompany these.

  • #2
    There is a small two way design names Choti that uses the same Dayton driver as the ne that you are using along with a tweeter on this forum. There is also a relatively inexpensive design for a 8" subwoofer on youtube by a contributor named 123Toid https://www.youtube.com/watch?v=MoNAu0QQMGU 123Toid also has an inexpensive subwoofer design with a 10" woofer, check him out. The only drawback to the first noted design is that there are two passive radiators and along with the woofer and plate amp so all vertical surfaces are used. Very cool "out of the box" enclosure design and nice cnc work. These speakers would work well as rear speakers in the eventual 5.1 setup..

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    • #3
      beautiful craftsmanship!

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      • #4
        Originally posted by randyohoh View Post
        There is a small two way design names Choti that uses the same Dayton driver as the ne that you are using along with a tweeter on this forum. There is also a relatively inexpensive design for a 8" subwoofer on youtube by a contributor named 123Toid 123Toid also has an inexpensive subwoofer design with a 10" woofer, check him out. The only drawback to the first noted design is that there are two passive radiators and along with the woofer and plate amp so all vertical surfaces are used. Very cool "out of the box" enclosure design and nice cnc work. These speakers would work well as rear speakers in the eventual 5.1 setup..
        Thank you for the helpful links. I really like the looks of that 8" sub. We aren't looking for anything crazy big or loud, this will go in a small living room, but I would like something that gets us to about 35 hz comfortably at an impact full spl. I feel like a 10" is probably going to be the better choice but I haven't decided yet. Not going to start buying until I'm done with these little guys. Sent from my SM-G950U using Tapatalk

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        • #5
          Made some progress this week. Started by sanding everything well. Then glued the sides together into a square, and then glued on the back plate.


          After the box was mostly assembled I applied non-wax shellac to the boxes to seal them and prepare the surface for vinyl.






          Next, I cut felt to fit inside the boxes and glued it in.





          I turned my attention to the wings. Using semi-glass lacquer I gave each side two coats. I am very happy with how nicely the deft semi gloss worked.






          Finally I glued on the face and sanded the edges flat so that when the vinyl is applied it will match up evenly.



          Last steps are to spray the face, apply the vinyl and reinstall the electronics.

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          • #6
            Nice work, nice documentation.

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