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Last Hurrahs Build - finally got started

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  • Last Hurrahs Build - finally got started

    Little time for speakers these days, but finally got underway yesterday. Not sure how fast things will progress. But will add to this as I get going. The Last Hurrahs no longer involve MDM55's and AC130's. I traded the MDM55's to Paul C. for a computer. I did not want to do the odd-shaped flanges anyway. :o

    The lineup top to bottom will now be CSS LD25X, Seas U18/RNX, and 2 X Usher 8955A. Models extremely well. Yes, I know, it is a 3-way derivative of the Malbecs, but I'll bet it will be a darned good one! Certainly will be more efficient and dynamic. For those noticing the 8955A's are NLA, it models very similarly with the RS225's.

    These are the backs. I used a 6" aluminum door threshold as a guide and the circular saw to make the cuts. Worked very well and did not have to get out the table saw.

    [IMG][/IMG]

    This is the shape I am headed for. Will keep you posted.

    [IMG][/IMG]

  • #2
    Re: Last Hurrahs Build - finally got started

    looking good Maynard!
    https://www.facebook.com/Mosaic-Audi...7373763888294/

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    • #3
      Re: Last Hurrahs Build - finally got started

      That's a great set of drivers Maynard. Can we talk you into putting that LD25X into one of Dave Pellegrene's small waveguides to better match that 7" woofer?
      R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
      Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

      95% of Climate Models Agree: The Observations Must be Wrong
      "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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      • #4
        Re: Last Hurrahs Build - finally got started

        Pete, I'm crossing about 2300 - 4th LR acoustic Overall system sensitivity will be about 90db. Tell me what I will hear different and under what conditions that will justify use of a waveguide.

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        • #5
          Re: Last Hurrahs Build - finally got started

          Originally posted by maynardg View Post
          Pete, I'm crossing about 2300 - 4th LR acoustic Overall system sensitivity will be about 90db. Tell me what I will hear different and under what conditions that will justify use of a waveguide.
          Hey Maynard, it's not so much for the improved distortion performance, but for the better off axis match. At 2300Hz, the woofer will already show some off axis droop, and the tweeter will be almost pure omni, so just above the XO point there will be some extra off axis energy compared to just below the XO point, especially with 4th order slopes.

          With a shallow guide, you also get acoustic alignment which should offer up the possibility of 2nd order LR instead of 4th.
          R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
          Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

          95% of Climate Models Agree: The Observations Must be Wrong
          "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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          • #6
            Re: Last Hurrahs Build - finally got started

            I'll contact Dave. Perhaps he has something small and round. Given the lines of the design, I don't think a square form will work well aesthetically. Total width at the top is only 7". I believe I'll be using rotary cut bubinga on these. Solid wood on the top.

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            • #7
              Re: Last Hurrahs Build - finally got started

              Maynard, I think I am not alone in being excited for this build to be starting.
              Don't listen to me - I have not sold any $150,000 speakers.

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              • #8
                Re: Last Hurrahs Build - finally got started

                It has been a couple of months, but I am back at it. I highly recommend using a long aluminum threshold as I have here for interesting angle cuts. Cut the tops, bottoms, and sides today. Gotta go out and get some fresh glue for glue-up in the AM.



                And I have to mention my Porter-Cable 345 Saw Boss 6" circular saw. Light, left hand blade, a wonderful, but sadly discontinued saw. Never breaks a sweat after maybe 20+ years. Through almost anything like butter.

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                • #9
                  Re: Last Hurrahs Build - finally got started

                  Originally posted by maynardg View Post
                  It has been a couple of months, but I am back at it. I highly recommend using a long aluminum threshold as I have here for interesting angle cuts. Cut the tops, bottoms, and sides today. Gotta go out and get some fresh glue for glue-up in the AM.



                  And I have to mention my Porter-Cable 345 Saw Boss 6" circular saw. Light, left hand blade, a wonderful, but sadly discontinued saw. Never breaks a sweat after maybe 20+ years. Through almost anything like butter.

                  this project is beyond the threshold of my abilities. get it threshold? lol. no seriously, i will be checking this one out.

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                  • #10
                    Re: Last Hurrahs Build - finally got started

                    Nice. I have the father to that saw. Left blade too. My Father-n-Law has THAT saw. Cuts everything like butter.
                    I have to agree with Pete. Make music really sweet off axis.
                    " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                    Quote Originally Posted by hongrn. Oct 2014
                    Do you realize that being an American is like winning the biggest jackpot ever??

                    http://www.midwestaudioclub.com/spot...owell-simpson/
                    http://s413.photobucket.com/albums/pp216/arlis/

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                    • #11
                      Re: Last Hurrahs Build - finally got started

                      Originally posted by maynardg View Post
                      Pete, I'm crossing about 2300 - 4th LR acoustic Overall system sensitivity will be about 90db. Tell me what I will hear different and under what conditions that will justify use of a waveguide.
                      can I ask why you are crossing 4 th order at 2300 ? also, I am not sure about the measurements, but just had a friend that measured the U18 send me his measurements and at 2300 hz at 30 degree off axis the driver is only a few db down and about 5 at 60 degree. I really I am not sure if a wave guide is going to get you much.
                      craigk

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

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                      • #12
                        Re: Last Hurrahs Build - finally got started

                        I tend to find the place where the drivers want to work without a lot of heroics. At about 2300, with few XO parts, they just want to snap into place at LR4 acoustic. Of course, once in the box, I'll be doing a lot of tweaking and experimentation. No waveguide, BTW. Seems to work OK without. Sim does not seem to lose all that much off-axis. If I am very far off axis, I am just listening passively anyway.

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                        • #13
                          Re: Last Hurrahs Build - finally got started

                          I am glad that you decided no wave guide. when you get the drivers in the box and take some measurements I would sure look at second order on that mid. one good thing, it is a very easy driver to work with. by the way, this is going to be one nice speaker.
                          craigk

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

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                          • #14
                            Re: Last Hurrahs Build - finally got started

                            Pin them up, clamp them down. I pay most attention to the angles when cutting. Then I tend to cut a bit large for my sides. Makes alignment easier. After things are dry, I will use a router or sand the edges down. Glue will pop off in about an hour or two with some quick chisel work. Don't have to worry about glue soaking or anything because it will eventually be veneered.

                            A nice part of having an indoor space for glue-up is that I can use the nailer at 4:00AM!

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                            • #15
                              Re: Last Hurrahs Build - finally got started

                              I bet it is difficult to cut window braces when you have compound angles. Do you do those on your table saw?
                              Craig

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