Atari - It means "to hit a target".

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  • Reet
    Senior Member
    • Dec 2007
    • 566

    Atari - It means "to hit a target".

    Definitely the fanciest thing I've done yet, however I've only built part of it. I've cheated a little bit on this one by purchasing the cabinets and stands second hand from another DIYer, toddw . The cabinets are beautiful curly cherry, with a very nice polished polyurethane finish. Some ceramic tiles and stuck to the inside, making a nice constrained layer and a nice dead cabinet. The stands are an interesting design, some kerf cuts and thin strips of ash are pinched against a centre support. Of course I took some inspiration to complete a new baffle.

    Recently I have found and joined the local Men's Shed, which has a little hobby CNC. It's been a fun process to learn the CNC and engage with a bunch of other local woodworkers, they're a great bunch and have been very encouraging.

    Having the cabinets already completed, enabled me to focus all of my efforts on creating a nice new baffle to complement them. For this project, I had always wanted to mill a waveguide right into the baffle, and that's exactly what I did here. The CNC also came in handy to cut precise curves to create the lamination pattern. I used American Cherry, and the accent is some African Mahogany left over from a previous project. The finish is Osmo Top Oil which apart from the price is fantastic finish, thanks DaveFred for the recommendation.

    This cabinet was specifically designed for the Satori MW16P, and from my previous driver testing, I had wanted to use the Melodavid Be28 with it. You heard me. The Melodavid Be28 shown to be very well capable of waveguide loading without being problematic in the top octave. The tweeter has a nice flat mounting surface with the faceplate removed, so installation is simply to clamp it from behind. I squished it in place with a layer of auto sound damping goo and a few layers of craft foam.

    Woodwork
    The baffle was built as two halves in a mirror image, the curved cut on CNC with a 1/8" bit, and then small 1/8" strips of mahogany were cut on the table saw, and clamped together. The two halved were then glued and clamped with the vertical strip down the middle to bring it together, then planed flat.

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    The holes were then cut on the CNC, a 1/4" end mill used for the woofer and to remove the bulk of the material for the waveguide. A 1/4" round nose end mill was used to cut the waveguide profile, with 10% step over so that minimal sanding was needed to clean it up. I cut the throat of the waveguide just barely undersized so that I could sand it to the final diameter.
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    Only 220 grit was used for sanding to clean it up.
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    The baffle was then stuck to the cabinet with carpet tape and trimmed down to exact size.
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    The chamfers / facets were then cut. A simple table saw jig was used for the facets on the sides. Sanded again with 220 to roll over the sharp edges.
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    The cabinet had an inset frame, about 5/8". A simple frame was cut from MDF scraps that will be used for attachment with a weather stripping seal. Awkwardly screwed in from behind in the corners. The extra plywood blocks are for mounting the tweeter.
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    Getting some finish applied. Osmo Top Oil.
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    My tweeter installation method. Sandwich clamped with a layer of auto damping goo and a few layers of craft foam. Famous last words "that's not going anywhere".
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    The downside here is that it is a hard dome tweeter with no protective grill, so keep your curious fingers out of there. I don't have kids...

    One speaker fully assembled and ready for measurements.
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    Next up, measurements and crossover design.


    Last edited by Reet; 19 May 2024, 13:51 Sunday.
    https://discord.gg/h5SuNKDJfx
  • Reet
    Senior Member
    • Dec 2007
    • 566

    #2
    The Crossover
    For this speaker, I already had a good idea of the driver performance from previous testing in a common basic cabinet here. Measurements were completed for this cabinet horizontally for the woofer, and horizontal and vertical for the tweeter, since it has an elliptical waveguide shape.

    Horizontal woofer response, 15deg increments:
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    Horizontal tweeter response, 15deg increments:
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    Even though both are excellent performing drivers, the 1.5kHz dip of the Satori threw things for a bit of a loop, it took a fair bit of fine tuning to get right without requiring either lots of parts or abnormally large components. After evaluating several different circuits, I listened to the best 2 options via APO EQ (instruction here). I finally landed on the following design in my attempts to balance all aspects. This crossover keeps the crossover frequency at 2kHz where it has the best distortion performance, and provides a mild impedance load overall.

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    Evaluating distortion, the drivers appear to be operating in its ideal range. What distortion? The following tests where completed at 315mm disatance, with the mic placed half way between the midwoofer and the tweeter. SPL was set for 96dB at the mic, was was 4.1V from the amp.

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    To evaluate any potential cabinet issues, I completed nearfield measurements at 1V, presenting 108dB at the mic. Range from 100Hz and up is clear of resonances, great!

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    Time to enjoy

    Last edited by Reet; 19 May 2024, 14:39 Sunday.
    https://discord.gg/h5SuNKDJfx

    Comment

    • Steve Manning
      Moderator
      • Dec 2006
      • 1900

      #3
      Very nice work Reet! Very cool that you have a local group of woodworkers you can work with.
      Hold on to your butts - It's about to get Musical!



      WEBSITE: http://www.smjaudio.com/

      Comment

      • Reet
        Senior Member
        • Dec 2007
        • 566

        #4
        Thanks! I definitely recommend checking out your local Men's Shed and maker spaces.
        https://discord.gg/h5SuNKDJfx

        Comment

        • theSven
          Master of None
          • Jan 2014
          • 1428

          #5
          WOW! The baffles are stunning and I like the interesting look of the stands too. Looking forward to the measurement and crossover design. I hope you put these to good use this summer for listening.
          Painter in training

          Comment

          • Reet
            Senior Member
            • Dec 2007
            • 566

            #6
            Thanks Sven. It's been quite an adventure. This is the first speaker baffle I've run on the CNC apart from the simple baffle inserts from all my previous driver testing. There's a little anxiety in this, one wrong setting in the CAM software or error in set up process and the board could be ruined. I think I came out pretty lucky with this one. There are flaws of course, but I won't tell you about them, but they are there to remind you that a human was involved .

            The crossover design is finalized, I'm just assembling it now over the next few days and gathering some data to present nice charts and graphs.
            https://discord.gg/h5SuNKDJfx

            Comment

            • Efalegalo
              Senior Member
              • Jan 2007
              • 140

              #7
              Beautiful build. Did you design the waveguide?

              Comment

              • Reet
                Senior Member
                • Dec 2007
                • 566

                #8
                Yes. I tested a couple profiles, and landed on what ultimately is a copy of Visaton WG148 squished into an elliptical shape, a bit wider and not quite as deep. It's not a perfect waveguide, but it still works well and provides a unique visual when milled into hardwood.
                https://discord.gg/h5SuNKDJfx

                Comment

                • Reet
                  Senior Member
                  • Dec 2007
                  • 566

                  #9
                  Updated with crossover details
                  https://discord.gg/h5SuNKDJfx

                  Comment

                  • duvixan
                    Member
                    • Sep 2012
                    • 63

                    #10
                    ...and subjective listening impressions?..

                    Originally posted by Reet
                    the 1.5kHz dip
                    edge coating

                    Comment

                    • Reet
                      Senior Member
                      • Dec 2007
                      • 566

                      #11
                      I'm not big on subjective fluff, but I can say that subjectively, the target was hit. Maybe the most detailed speaker I've ever heard. I'm listening through an nCore amp and there's a clarity here that's just uncanny. The driver size does have its limits on the low end, they really need to be paired with a subwoofer to belt out the bass, but otherwise, just excellent 👌.
                      https://discord.gg/h5SuNKDJfx

                      Comment

                      • Reet
                        Senior Member
                        • Dec 2007
                        • 566

                        #12
                        Trying for a few nice photos while the sun was shining in for a few minutes.
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                        https://discord.gg/h5SuNKDJfx

                        Comment

                        • Reet
                          Senior Member
                          • Dec 2007
                          • 566

                          #13
                          theSven please approve above post #12, not sure why its been flagged.

                          JonMarsh?
                          Last edited by Reet; 20 May 2024, 10:20 Monday. Reason: tagging mods to fix stuff
                          https://discord.gg/h5SuNKDJfx

                          Comment


                          • theSven
                            theSven commented
                            Editing a comment
                            Approved. Sorry for not seeing this sooner. I had a crazy weekend and for once was actually away from keyboard.
                        • tktran
                          Senior Member
                          • Jan 2005
                          • 663

                          #14
                          That’s a gorgeous design.
                          I like the colour contrasting atari motif, and by use of the facets brings a kind of synergy to the baffle.
                          As good as any of the cabinets at the recent High End Munich!
                          You really made it yours. And I bet it sounds great too.

                          Congratulations!

                          PS. Can you tell us how the facets affected the directivity for the waveguided Be28 ie. before/after

                          PPS. I can see a 3 way…
                          Last edited by tktran; 19 May 2024, 22:25 Sunday.

                          Comment

                          • Reet
                            Senior Member
                            • Dec 2007
                            • 566

                            #15
                            Thank you Tanh, that's very kind.

                            I didn't do before/after with the facets on this particular baffle, so the result is what it is. In my test cabinet, I tested the Be28 in its stock form, the test cabinet is not as wide as this one however, and with just basic 1/2" roundover.
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                            In the same cabinet, I tested a waveguide which copied the Visaton WG148 profile, but squished a few mm shallower for 19mm material (WG148 is 21mm depth).
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                            Finally, this cabinet, wider, slightly different WG profile, and with facets.
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                            https://discord.gg/h5SuNKDJfx

                            Comment

                            • duvixan
                              Member
                              • Sep 2012
                              • 63

                              #16
                              Wow, the NE180W, dont see them very often
                              Great drivers too, on par with the Illuminators, some say..

                              Comment

                              • Reet
                                Senior Member
                                • Dec 2007
                                • 566

                                #17
                                Poor man's Illuminator .

                                I picked qty 8 of them up for a steal, still thinking of what I should do with them. Measurements available in my driver testing thread.
                                https://discord.gg/h5SuNKDJfx

                                Comment

                                • duvixan
                                  Member
                                  • Sep 2012
                                  • 63

                                  #18
                                  Smth like this maybe
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                                  Last edited by duvixan; 19 May 2024, 17:42 Sunday.

                                  Comment

                                  • Reet
                                    Senior Member
                                    • Dec 2007
                                    • 566

                                    #19
                                    Maybe a bit less obtrusive looking though.
                                    https://discord.gg/h5SuNKDJfx

                                    Comment

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