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  • Radiusaurus


    DESCRIPTION: Two way stand mount bookshelf. Open baffle tweeter flanked by four 3.5" full range drivers in an MMTMM configuration. Separate upper and lower 0.50 cu. ft. vented cabs. Large 5.75" radius round-overs.

    DRIVERS: Dayton ND90-8 3.5" full range (4 per channel). B & G Neo3 planar transducer with rear chamber removed (open baffle).

    CROSSOVER: Somewhere in the 1.7 to 2.5KHz range, 4th order.

    TUNING: FB: approximately 45Hz.

    FIT & FINISH: The entire baffle and top will be finished with 1/16" thick foam rubber gasket material. A brown racing stripe down the center will be flanked by black foam rubber round-overs. The sides will be pre-finished mahogany with black foam rubber accents.

    DIMENSIONS: OD: 27.5" H x 15" W x 18" D. Flat portion of baffle: 3.5" W x 27.5" H

    RULES: I reviewed the Indy requirements several times and I "think" I am in compliance. The tweeter is open back and covers 3 octaves, but the back wave will be somewhat scattered by obstructions, such as the xover and the upper and lower cabs (see attached detail drawing). Nonetheless, this appears to be a reasonable attempt for equal radiation to both the front and rear in the same driver bandwidth.

    Bill
    SideTowers: http://techtalk.parts-express.com/fo...corundum-build
    Totally Flat: http://techtalk.parts-express.com/fo...5-totally-flat
    Plumber's Delight: http://techtalk.parts-express.com/fo...notech-winners
    Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build

  • #2
    More baffle board detail:
    SideTowers: http://techtalk.parts-express.com/fo...corundum-build
    Totally Flat: http://techtalk.parts-express.com/fo...5-totally-flat
    Plumber's Delight: http://techtalk.parts-express.com/fo...notech-winners
    Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build

    Comment


    • #3
      Each baffle consists of 9 beveled-edge vertical sections, glued together with yellow wood glue and tape (see attached pics). I used high strength gorilla tape horizontally and standard masking tape vertically.

      The procedure I employed was a modified version of the donradick suggested hexadecagon method found in post #6 of this thread:

      Link: http://techtalk.parts-express.com/fo...er-diffraction

      The only tricky part was setting the bevel angles. They must be precise or the final glue-up will not come out to 90 degrees. Also, I carefully engineered the width of each vertical section to minimize the amount of final sanding required.
      SideTowers: http://techtalk.parts-express.com/fo...corundum-build
      Totally Flat: http://techtalk.parts-express.com/fo...5-totally-flat
      Plumber's Delight: http://techtalk.parts-express.com/fo...notech-winners
      Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build

      Comment


      • #4
        really nice
        craigk

        " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

        Comment


        • #5
          Wow, your usually outstanding challenging woodworking project!
          And I got a shoutout. too darn cool.
          IIRC, a large radius baffle will result in smoother on and off axis FR.
          Perhaps you could use a test baffle with 90 degree side edges and
          compare the FR to the large radius. I think all you would need to measure
          is the tweeter.

          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!
          SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
          My Voxel min sub Yet-another-Voxel-build

          Tangband W6-sub

          Comment


          • #6
            Hi Bill, I really like the look of your huge radius baffles! You have a knack for coming up with very unique and visually creative designs. My concern is with how vastly different your front and rear radiation patterns will be.
            Craig

            I drive way too fast to worry about cholesterol.

            Comment


            • #7
              Compliant!
              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:
              https://app.photobucket.com/u/wolf_teeth_speaker

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

              Comment


              • #8
                Thanks everyone. Don, you must have been reading my mind. I have measurements of this tweeter, mounted on my build of scottsehlin Matrix Revolution speakers. The baffle is 7 inches wide with 3/8" round-overs and custom facets. There is a picture of these speakers/facets over on the MAC site in the DakotaDIY archives section. I'll go get it and attach it when I get that far. I also built a large IEC test baffle recently with removable tweeter inserts, so I will be running up a set of comparative polar measurements on that large baffle as well. The IEC test baffle will be the control reference. Stay tuned.

                Craig, I see what you are saying. The upper and lower cabinets might produce a "midrangy" type narrow tunnel effect coming out the rear.
                SideTowers: http://techtalk.parts-express.com/fo...corundum-build
                Totally Flat: http://techtalk.parts-express.com/fo...5-totally-flat
                Plumber's Delight: http://techtalk.parts-express.com/fo...notech-winners
                Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build

                Comment


                • #9
                  Originally posted by 4thtry View Post

                  Craig, I see what you are saying. The upper and lower cabinets might produce a "midrangy" type narrow tunnel effect coming out the rear.
                  It might not be a big problem. Just something you need to correct in your crossover design.
                  Craig

                  I drive way too fast to worry about cholesterol.

                  Comment


                  • #10
                    Originally posted by 4thtry View Post
                    Craig, I see what you are saying. The upper and lower cabinets might produce a "midrangy" type narrow tunnel effect coming out the rear.
                    Your ingenuity always amazes me Bill. Keep pushing the envelope! You could angle those two cab walls away from the tweeter as they go back which would form more of a Y versus a tunnel. It might add a few inches of depth to keep the volume the same. Then you could add the "non-parallel walls" to your design write up.

                    The elephant in the room is the room

                    Comment


                    • #11
                      Looks like a nice design, I look forward to seeing and hearing it.

                      Comment


                      • #12
                        I did something very similar last year by kerfing BB ply. Had a few problems along the way (naturally), but managed to recover, and
                        I love the final result and will probably do this again.

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                        Attached Files

                        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!
                        SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
                        My Voxel min sub Yet-another-Voxel-build

                        Tangband W6-sub

                        Comment


                        • #13
                          WOW! What gorgeous round-overs...
                          Ann

                          Comment


                          • #14
                            +1. Really nice cabinets, Don! These look like about 2" radius, right? Very smooth. My round-overs will not be quite this elegant. I'll be covering mine with 1/16" thick foam rubber in an attempt to absorb or dampen any spurious HF reflections.
                            SideTowers: http://techtalk.parts-express.com/fo...corundum-build
                            Totally Flat: http://techtalk.parts-express.com/fo...5-totally-flat
                            Plumber's Delight: http://techtalk.parts-express.com/fo...notech-winners
                            Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build

                            Comment


                            • #15
                              Originally posted by ernperkins View Post

                              Your ingenuity always amazes me Bill. Keep pushing the envelope! You could angle those two cab walls away from the tweeter as they go back which would form more of a Y versus a tunnel. It might add a few inches of depth to keep the volume the same. Then you could add the "non-parallel walls" to your design write up.
                              Thanks Ed. I like your "Y" suggestion, but I already have the rectangular boxes knocked out. So I'll have to deal with this issue in the xover. Also, I'll be adding thin felt material to the tunnel walls, which should help a little too.
                              SideTowers: http://techtalk.parts-express.com/fo...corundum-build
                              Totally Flat: http://techtalk.parts-express.com/fo...5-totally-flat
                              Plumber's Delight: http://techtalk.parts-express.com/fo...notech-winners
                              Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build

                              Comment

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