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Anyone here built a double chamber reflex sub?

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  • Anyone here built a double chamber reflex sub?

    If so:
    1. Details ?
    2. Did you compare it to the equivalent single reflex subwoofer?
    3. Regardless, how did you like the results?

    FWIW, Here's a VERY ROUGH proposal I drew up for a slot ported DBR sub of about 5 cu.ft. net tuned to about 22 Hz for an RSS390HO 15" driver . I know the slot ports are a bit too skinny and should probably be split up further along their axes, but as I said, this is a rough design


    Thanks
    Attached Files

  • #2
    Re: Anyone here built a double chamber reflex sub?

    Do you have the modeled fr?

    Comment


    • #3
      Re: Anyone here built a double chamber reflex sub?

      Ive done a couple. One used the ROT of 1/3 2/3 volumes of each chamber. Interesting results, but not necessarily any better than a properly designed ported box.
      https://www.facebook.com/Mosaic-Audi...7373763888294/

      Comment


      • #4
        Re: Anyone here built a double chamber reflex sub?

        Originally posted by duanebro View Post
        Do you have the modeled fr?
        Not near my home computer right now in order to upload the winisd models, ...but i posted several modeled graphs on this thread: http://techtalk.parts-express.com/sh...gnments-please

        Thanks

        Comment


        • #5
          Re: Anyone here built a double chamber reflex sub?

          Originally posted by isaeagle4031 View Post
          Ive done a couple. One used the ROT of 1/3 2/3 volumes of each chamber. Interesting results, but not necessarily any better than a properly designed ported box.
          Interesting ?

          Comment


          • #6
            Re: Anyone here built a double chamber reflex sub?

            Yeah, it was used in a van. It hit the lower register very hard but having 2 peaks could make it a bit harder to tune. Great for dub step, not so much for pop music.
            https://www.facebook.com/Mosaic-Audi...7373763888294/

            Comment


            • #7
              Re: Anyone here built a double chamber reflex sub?

              This morning, I decided that since I haven't been able to find a lot of documented builds of DCR subwoofers, such a sub needed to be built and the results documented, for better or worse. I spent the afternoon refining the dimensions and the sketchup model. I couldn't attache the win isd model but basically its a 5 cu ft slot loaded double chamber reflex tuned to 22 Hz via four 5 x 1.5 " slot ports . Port dividers not shown in the sketch.

              I've started glue up and should have something to report in a day or two. After starting the build and looking at the size of the enclosure, I half wish I had built a TH instead, .. (but been there done that already, so what's the fun).
              Click image for larger version

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              • #8
                Re: Anyone here built a double chamber reflex sub?

                What you've got there is more of a dual chambered 6th order bp. Either way you will have 2 tuning freqs.
                https://www.facebook.com/Mosaic-Audi...7373763888294/

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                • #9
                  Re: Anyone here built a double chamber reflex sub?

                  Hi,
                  How does this become a 6th order BP. The driver will be in the left most ( larger chamber )? Unless the holey brace in the smaller chamber is the source of the confusion

                  Comment


                  • #10
                    Re: Anyone here built a double chamber reflex sub?

                    Comment


                    • #11
                      Re: Anyone here built a double chamber reflex sub?

                      Looks like a bandpass to me as well.

                      I saw a design years ago where the woofer was on the outside of the box. The chamber directly behind the woofer was ported into a lower chamber, and the lower chamber was ported to the outside of the box. I think it was called a double chamber reflex.

                      Comment


                      • #12
                        Re: Anyone here built a double chamber reflex sub?

                        Originally posted by rpb View Post
                        Looks like a bandpass to me as well.

                        I saw a design years ago where the woofer was on the outside of the box. The chamber directly behind the woofer was ported into a lower chamber, and the lower chamber was ported to the outside of the box. I think it was called a double chamber reflex.
                        Hi
                        Perhaps that would be the "fostex style" dcr
                        http://www.fostexinternational.com/d...3e_enclrev.pdf

                        Maybe that's the type of Dcr that Mjk spreadsheets can calculate ( I'm away from my main computer at the moment)

                        Comment


                        • #13
                          Re: Anyone here built a double chamber reflex sub?

                          Yeah the brace is what threw me. So what is your chamber volumes and tuning for each?
                          https://www.facebook.com/Mosaic-Audi...7373763888294/

                          Comment


                          • #14
                            Re: Anyone here built a double chamber reflex sub?

                            5 cu ft split into 2 chambers in the ratio 2:1

                            Tuning is around 22 Hz. Note that I split up the 12" x 1.5" wide slot port (accounted for in WinISD by designing with 4 ports instead of 2) via a divider to
                            1. slightly reduce the port area resulting in a slight reduction in the port length.
                            2. brace the slot port.
                            3. reduce the port aspect ratio from 12:1.5 to 5:1.5

                            I'll double check my volume calculations tomorrow before sealing the cabinet in case I need to balance anything out

                            Comment


                            • #15
                              Re: Anyone here built a double chamber reflex sub?

                              I built a DCR for my computer speakers. I choose that enclosure because a DCR can provide lower tuning while controlling the excursion. It's great for full-range drivers that have low xmax. For a sub, I have yet to want to listen to one that needed more xmax. I tend to prefer sealed subs anyway.

                              Still an interesting project. Do you have a standard reflex enclosure to compare it to?
                              - John

                              "Injustice anywhere is a threat to justice everywhere." - Dr. M. L. King
                              www.BuildTheDream.org

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