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Home/Pro 8" 2-way: RS28A and B&C 8BG51

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  • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

    Send your tweeters to Dave Pellegrene. I'm sure he'd work with you to come up with a suitable guide. Plenty of folks like the TDFC/TDC and having a ready made guide that works might find an audience.
    I would if I was home but I'm working in Brazil at the moment and will be here for a little while and that's what this project is for... :/
    If nobody comes up with something in a few months I may order one 27TDFC and have it shipped to him directly.

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    • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

      Originally posted by markk View Post
      Well, not in my experience. See the graphs below.

      However, I have to say that, when pushing a tweeter that low, there is a lot of unit to unit variation. Not every TDFC and not every RS28F will go as low. You are pushing the limits. Individual testing is needed if you're pushing it this low. Including using any waveguide. You can't assume the WG will automatically lower distortion.
      Silly me, I forgot to check your five tone burst testing. :p
      And I completely agree about unit to unit variation and pushing a dome tweeter down to 1khz.

      Comment


      • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

        Originally posted by buzzforb View Post
        Pete, and others,
        What is the general opinion, if any, on zobel networks?
        Usually, the crossover network can steer the response to the proper shape without zobels.

        Zobels can be useful when trying to shape the response by altering the crossover "Q" near cutoff, but in most cases they're unneeded.
        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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        • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

          Thank you. Got my 10g40's in. Dave's waveguide, as well as the TL N26c should be here Monday. Putting the woofer in a MLTL 42" long giving -3dBa of around 45-48Hz. Gonna need s one x over help. For quick listen, I will use dps, but reading up on Bagby's software now in order to use his XO designer. Need to create Frd file for the two components.

          Comment


          • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

            Originally posted by buzzforb View Post
            Thank you. Got my 10g40's in. Dave's waveguide, as well as the TL N26c should be here Monday. Putting the woofer in a MLTL 42" long giving -3dBa of around 45-48Hz. Gonna need s one x over help. For quick listen, I will use dps, but reading up on Bagby's software now in order to use his XO designer. Need to create Frd file for the two components.
            Different woofer, different tweeter, different waveguide . . . not quite sure how that applies to this thread.

            You'll need a mic to measure the FRDs before you can generate the transfer functions for the DSP.

            Nice tweeter choice though.
            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


            • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

              Very true. Sorry for OT. Will speak strictly of your tweeter, waveguide ,and woofer in the future.

              Comment


              • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                Originally posted by buzzforb View Post
                Very true. Sorry for OT. Will speak strictly of your tweeter, waveguide ,and woofer in the future.
                Better yet, start a new thread documenting your build. I'm sure there would be plenty of interest by others on your progress, me included. ;)
                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


                • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                  Pete,

                  Can you double check your waveguide for the exact depth? I'm also curious if the throat is 1.5" or bigger. It seems 1.5" is the best, but I thought you mentioned it was wider than that.

                  Comment


                  • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                    Originally posted by Erich H View Post
                    Pete,

                    Can you double check your waveguide for the exact depth? I'm also curious if the throat is 1.5" or bigger. It seems 1.5" is the best, but I thought you mentioned it was wider than that.
                    It's 2" deep, and the opening matches the opening of the tweeter flange, so it's 1.625" wide. I'd be interested in seeing the results of closing down the opening to 1.5".
                    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


                    • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                      OK, here's an off axis set along with a near field of each driver. ~10 degree increments. Listening axis is actually 15 degrees as I am doing all my voicing with the speakers cross firing, 45 degrees, while I sit at the apex of an equilateral triangle formed by my head and the speakers.

                      Attached Files
                      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


                      • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                        That off axis performance looks very well controlled and the directivity of the woofer and tweeter seem to match well around crossover.

                        What did your 2.83v sensitivity end up at?

                        OK, here's an off axis set along with a near field of each driver. ~10 degree increments. Listening axis is actually 15 degrees as I am doing all my voicing with the speakers cross firing, 45 degrees, while I sit at the apex of an equilateral triangle formed by my head and the speakers.

                        Loren Jones

                        http://techtalk.parts-express.com/sh...-sound-drivers

                        http://techtalk.parts-express.com/sh...for-live-sound

                        Comment


                        • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                          Originally posted by lorenmjones View Post
                          What did your 2.83v sensitivity end up at?
                          That I'm not quite sure of. Based on the transfer functions and the theoretical 90dB/1W at 100Hz, I'd guess I wound up at about 87.5dB/2.83V
                          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


                          • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                            That's pretty good for .75 cf with extension in the upper 40's.


                            That I'm not quite sure of. Based on the transfer functions and the theoretical 90dB/1W at 100Hz, I'd guess I wound up at about 87.5dB/2.83V
                            Loren Jones

                            http://techtalk.parts-express.com/sh...-sound-drivers

                            http://techtalk.parts-express.com/sh...for-live-sound

                            Comment


                            • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                              Originally posted by lorenmjones View Post
                              That off axis performance looks very well controlled and the directivity of the woofer and tweeter seem to match well around crossover.

                              What did your 2.83v sensitivity end up at?
                              Hey Pete is this 0-80 degrees horizontal axis? This was suppose to be quoting post #265.
                              http://www.pellegreneacoustics.com/

                              Trench Seam Method for MDF
                              https://picasaweb.google.com/101632266659473725850

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                              • Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

                                Originally posted by davepellegrene View Post
                                Hey Pete is this 0-80 degrees horizontal axis? This was suppose to be quoting post #265.
                                Yes, 0-80 in approximately ten degree steps.
                                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

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