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  • EconoWave SR Compact Directivity

    At a recent AK Fest, Joe D'Appolito suggested that research at Snell revealed perforated metal being the most acoustically transparent grille material as the reason it was incorporated into their products. John used stock JBL grilles in this design, somewhat more forward and with more curvature than I have installed it here, but the data is informative:




    In each pairing below, without grille is first, followed by grilled:








    Attached Files
    Last edited by Zilch; 08-06-2010, 03:57 PM.

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    • Re: Flex Your PCD Mettle:

      Looks like just a bit of HF attenuation, but at least it's fairly uniform.
      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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      • EconoWave SR Compact Directivity Continued

        Pete is QUICK! ;)





















        Generally, I confirm Snell's findings per D'Appolito - there's a bit more ripple from these 1/4" perfs, but as Pete observes, the response is uniform; little compromise for having the requisite protection from flying beer bottles.

        Though the the cab edge overhang has been reduced from 1.5" to 1" ahead of the grille, its apparent effect remains a key feature in the directivity plots.

        Of note
        Attached Files
        Last edited by Zilch; 08-06-2010, 02:32 AM.

        Comment


        • Re: Round #5.1 - EconoWave SR Compact

          Originally posted by Zilch View Post
          I've never built one vertically like you suggest, but it's unlikely that will work, as the interference nulls would severely limit the usable beamwidth in that orientation.... :(
          That dont sound good.

          I have absolutely no choice, if I want to use econo-waves as my mains, but to orientate the waveguide vertically, beside the woofer, in my application.

          But both the wall mounted Speaker and the single listening location are fixed, and almost exactly on-axis of the waveguide, and the room itself is deeper than it is wide. Off axis response, I assume, is irrelevant to me.

          Is that not going to be a doable build?

          ..... would a round or square waveguide mitigate the interference nulls?

          Comment


          • Re: Round #5.1 - EconoWave SR Compact

            Originally posted by Flacjunky View Post
            That dont sound good.

            I have absolutely no choice, if I want to use econo-waves as my mains, but to orientate the waveguide vertically, beside the woofer, in my application.

            But both the wall mounted Speaker and the single listening location are fixed, and almost exactly on-axis of the waveguide, and the room itself is deeper than it is wide. Off axis response, I assume, is irrelevant to me.

            Is that not going to be a doable build?

            ..... would a round and square waveguide mitigate the interference nulls?
            The nulls will always be there, it's their location that matters. The reason for a vertical orientation for mid and woof is to create a wide horizontal beam. The nulls will occur in the vertical direction with a vertical mounting orientation. If you put the drivers side by side, then the nulls will be in the horizontal direction, creating a mess of things as you move around the room since your ears occupy a narrow range vertically and a wide range horizontally.
            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.

            Comment


            • EconoWave SR Compact:







              If building with standard EconoWave PC boards, choose Solen or Jantzen 10 uF C1 to fit component mounting hole spacing. Insert lowpass parallel notch filter (R3, C4, L3) in lieu of J1.

              Attached Files

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              • Flex It Round #6.0 - EconoWave High Power Pro

                How much damage can we do with THESE in Dayton KD Trap Kits?




                [Hint: 7212.... :D ]
                Attached Files

                Comment


                • Re: Flex Your PCD Mettle:

                  Dr. Megapower will have the cauldron steamin', shortly...
                  Mongo only pawn in game of life
                  ____
                  Ed

                  Comment


                  • Re: Flex Your PCD Mettle:

                    The lit says 2452H-SL is titanium/damped....is that the Aquaplas version?

                    Can't wait to see what you make that DD woofer do.
                    Do you think JBL built the 10-15k bump into the HF for the sake of intelligibility/hyped air? (7212/95DPC SR product):
                    http://www.google.com/url?sa=t&sourc...apTwen15yQUNfg
                    Looks like this design could work in both Hi Fi or SR applications.
                    Cool.
                    http://www.nytimes.com/2010/10/14/bu...html?src=busln

                    http://mixonline.com/mag/audio_new_york_metro_46/

                    Comment


                    • Re: Flex Your PCD Mettle:

                      Yes, Aquaplas-damped 4" titanium diaphragm, 4" voice coil, 1.5" exit.

                      I'm starting with the one in front first, tho, which is 2432H, 3" titanium, 3" voice coil, 1.5" exit, to build a compact version of this:

                      http://www.jblpro.com/catalog/suppor...e=3&docid=1476

                      Can't guess why'd they'd bump the HF in VP like that; I doubt the polars will show a deficit off-axis there, and what measurements I've done do not suggest having to do it to get extension to 20 kHz.

                      I agree; HT mains and/or SR monitors/mains....
                      Last edited by Zilch; 08-07-2010, 04:40 AM.

                      Comment


                      • Re: Round #5.1 - EconoWave SR Compact

                        Originally posted by Flacjunky View Post
                        But both the wall mounted Speaker and the single listening location are fixed, and almost exactly on-axis of the waveguide, and the room itself is deeper than it is wide.
                        How much space do you have to work with?

                        Can you mount the waveguide on the top (or bottom) of the wall mounted speaker box? It doesn't have to be on the baffle. Call it "thinking outside the box" :rolleyes:

                        Comment


                        • Re: Round #5.1 - EconoWave SR Compact

                          Originally posted by donprice View Post
                          How much space do you have to work with?

                          Can you mount the waveguide on the top (or bottom) of the wall mounted speaker box? It doesn't have to be on the baffle. Call it "thinking outside the box" :rolleyes:
                          Each baffle is 27" wide x 21" tall.



                          The cabinet is against the ceiling, with the HDTV to be located directly underneath cabinet.

                          I dont see an external option. I was thinking about something like this, but angling down instead of up.

                          Last edited by Flacjunky; 08-07-2010, 12:35 PM.

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                          • Re: Flex Your PCD Mettle:

                            Is that the ceiling at the bottom of your pic?

                            [I'm not getting this.... ]

                            Comment


                            • Re: Flex Your PCD Mettle:

                              Originally posted by Zilch View Post
                              Is that the ceiling at the bottom of your pic?

                              [I'm not getting this.... ]
                              No, its on the wall, up against the (Black) ceiling.

                              Zoomed Out



                              Its basically an 8' Long Soundbar w/ 7.5 Cu. Ft. per Main. :o

                              Profile

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                              • Re: Flex Your PCD Mettle:

                                If you've got 21" on the angled surface, you're good to go with many of the designs posted in this thread that do not use the QSC 152i waveguide. John's cab that I used in SR Compact is just a scritch over 21" tall, for example.

                                I'd put the waveguide closest to the wall, probably, and wedge it outward (forward) a bit, if necessary, to aim it (vertically) at the listening area....

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