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  • Double Chamber Reflex info?

    My (basic) understanding, if correct, is that the cabinet size remains the same as a standard BR (for the chosen driver) but is split in two parts, the driver in the larger cavity (roughly two thirds); both cavities are ported with the third port joining each. Not sure if all ports are the same size/length or how to calculate ..


    Looking for any info or designs to understand better and also if their advantages include extra sensitivity or bass extension

    thanks

  • #2
    Re: Double Chamber Reflex info?

    Originally posted by bill poster View Post
    My (basic) understanding, if correct, is that the cabinet size remains the same as a standard BR (for the chosen driver) but is split in two parts, the driver in the larger cavity (roughly two thirds); both cavities are ported with the third port joining each. Not sure if all ports are the same size/length or how to calculate ..


    Looking for any info or designs to understand better and also if their advantages include extra sensitivity or bass extension

    thanks
    The best articles on Double Chamber Reflexes appeared in Speaker Builder Magazine. There was an Australian, Paul Sechi if I remember correctly who thoroughly analyzed and modeled the design. Yeah, he was able to get 20 something Hz from a 6.5 inch woofer, but it required a washing machine sized enclosure.
    I consider it to be a dead end design.

    Comment


    • #3
      Re: Double Chamber Reflex info?

      Wolf's got a TB W3 (in the Showcase I believe) that uses a double chamber. I think the 1/3 - 2/3 volume split is correct, and I also think all 3 vents are the same dims.

      Comment


      • #4
        Re: Double Chamber Reflex info?

        These don't really extend any deeper than a standard vented box of the same overall size, but what you do gain is more control of the driver's excursions and lower overall distortion due to the ports controlling the cone over a wider bandwidth.
        Click here for Jeff Bagby's Loudspeaker Design Software

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        • #5
          Re: Double Chamber Reflex info?

          you are essentially correct. Design a ported box with 2 ports, split the box into 1/3 and 2/3s volume. most usually put the driver in the larger section just because it has more room. make an extra port the same size as called for in the 2-port original box to connect the 2 chambers. This design will help reduce cone excursion in the upper passband of the woofer as the smaller chamber resonance increases loading. at the lower end both champers act as a single larger volume and tune the box to the lower freq. This type of design is usually used to control cone movement at the upper tuning freq. but also has the effect of decreasing distortion in that region as well.

          Comment


          • #6
            Re: Double Chamber Reflex info?

            Originally posted by Jeff B. View Post
            These don't really extend any deeper than a standard vented box of the same overall size, but what you do gain is more control of the driver's excursions and lower overall distortion due to the ports controlling the cone over a wider bandwidth.
            Yeah, you cannot break the laws of physics. If you want to tune it lower, you'll have to build it bigger.

            Comment


            • #7
              Re: Double Chamber Reflex info?

              Ah! also found a Tech Talk thread from 2013, gives great info http://techtalk.parts-express.com/sh...php?236975-Dcr

              edit just spotted this book by Paul Sechi from 1992

              https://books.google.co.uk/books/abo...AJ&redir_esc=y

              Comment


              • #8
                Re: Double Chamber Reflex info?

                Claudio Negro has a good DCR article here:
                http://www.claudionegro.com/ (Projects -> Speakers -> Dual Chamber Reflex)

                I built a DCR MTM with the SB13:
                Click image for larger version

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                IMHO, it's not hard at all to divide a particular volume into 2/3 and 1/3 sub enclosures, but it can be "interesting" to fit in
                all the ports without running into something. I like the design concept - seems like the bass is a bit better controlled.

                Hope this helps!

                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


                • #9
                  Re: Double Chamber Reflex info?

                  http://micka.de/org/en/4kammer2chassis_en.php

                  You can model pretty much whatever you want here^^^.

                  Chris- I have a W3-517S1 DCR project in the 'bucket, and a W4-1337 3CR ('3CR-Ti') project in the showcase.

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

                  Comment


                  • #10
                    Re: Double Chamber Reflex info?

                    Originally posted by Wolf View Post
                    http://micka.de/org/en/4kammer2chassis_en.php

                    You can model pretty much whatever you want here^^^.

                    Chris- I have a W3-517S1 DCR project in the 'bucket, and a W4-1337 3CR ('3CR-Ti') project in the showcase.

                    Later,
                    Wolf
                    Thanks Wolf, much appreciated. I modelled the 5" satori - around 7 litres and 57hz tuning - The biggest problem is trying to fit the bloody ports in ! they only fit if max 1.25 inch diameter. Not sure if thats enough..

                    Comment


                    • #11
                      Re: Double Chamber Reflex info?

                      Originally posted by bill poster View Post
                      Thanks Wolf, much appreciated. I modelled the 5" satori - around 7 litres and 57hz tuning - The biggest problem is trying to fit the bloody ports in ! they only fit if max 1.25 inch diameter. Not sure if thats enough..
                      Fitting the ports in is my main problem with DCR designs!

                      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


                      • #12
                        Re: Double Chamber Reflex info?

                        I've heard "capable" 5"ers (which I'd assume that Satori IS) chuff w/1.75" id ports. Rounding over the exits can help some.

                        Comment


                        • #13
                          Re: Double Chamber Reflex info?

                          Originally posted by Chris Roemer View Post
                          I've heard "capable" 5"ers (which I'd assume that Satori IS) chuff w/1.75" id ports. Rounding over the exits can help some.
                          is that a single or double port BR? I was hoping that with a DCR having two external 1.25" ports it may be borderline ok

                          Comment


                          • #14
                            Re: Double Chamber Reflex info?

                            Originally posted by bill poster View Post
                            is that a single or double port BR? I was hoping that with a DCR having two external 1.25" ports it may be borderline ok
                            Unless you plan to drive it with a lot of power, two 1.25" ports should be fine.
                            Click here for Jeff Bagby's Loudspeaker Design Software

                            Comment


                            • #15
                              Re: Double Chamber Reflex info?

                              Originally posted by Jeff B. View Post
                              Unless you plan to drive it with a lot of power, two 1.25" ports should be fine.
                              Thanks Jeff. Now thinking a slotted port is a better solution and less clumsy looking, as I can maximise the length (and therefor the vent area) along the top and bottom of the cab; in this case exiting at the rear. And as the cab dimensions are taller than deep, I can run the internal vent up the back.. fingers crossed it will fit

                              Am I right in thinking slot ports chuff less the circular ports?

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