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1.75” port options

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  • 1.75” port options

    My sub build looks like a 1.75” port would be about ideal. 2” is just too long and 1.5” too much port velocity. The problem is that I still need upwards of 13” which requires one elbow.


    Are they any options out there that I can get the length need using an elbow?

    I also occured to me that maybe I could use a flexible hose? Would that work? If so it would probably work fit wise.

    Thank you all

  • #2
    I was just contemplating something like this over the weekend. I thought about a piece of flexible exhaust pipe but discarded the idea because it's not smooth inside. What about going to your local exhaust shop and getting them to bend a solid piece of pipe? Have them bend it so both sides of the bend are overlength so it can be cut down and tuned.

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    • #3
      You have a source for 1.75" pipe? Unusual size..

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      • #4
        Never tried it, but a sturdy thick-wall rubber hose might work fine.
        Francis

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        • #5
          Originally posted by Dukk View Post
          You have a source for 1.75" pipe? Unusual size..
          1 3/4 id is 1 7/8" od. in 16 gauge mild steel. Should be able to get a piece without a problem. If the exhaust shop doesn't have it try a place that builds headers.

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          • #6
            Ports are usually longer than they need to be due to varying things. If you install it close to an inside wall, for example, or because we generally underestimate how much air space is consumed by drivers, crossovers, stuffing, braces. My personal rule of thumb is to trim 10% or so off calculated length. More if I anticipate effective lengthening of the port due to panel proximity.

            Fkex hose will work, I suggest coating it liberally with epoxy or other hardening agents though.
            Don't listen to me - I have not sold any $150,000 speakers.

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            • #7
              Oh, and the port tube itself consumes considerable internal volume.
              Don't listen to me - I have not sold any $150,000 speakers.

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              • #8
                Sorry, one more comment. The 2" will likely work because of the comments above. Depending on gross volume of the enclosure, that is.
                Don't listen to me - I have not sold any $150,000 speakers.

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                • #9
                  Thank you everyone. When I mentioned flexible hose I was thinking of reinforced PVC. I now my Kef LS50 has a flexible section that they used to deter port resonance. So I figured maybe it would work.

                  Thank you Johnyrichards, I am going to play with Winisd and see how slight differences (10%) make and also vary the box volume a little in the modeling to make sure nothing wonky happens.

                  Much appreciated.

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                  • #11
                    Originally posted by tomzarbo View Post
                    Click image for larger version

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                    The actual inner dimension of ABS plastic 1.5" pipe is really 1.61" or so if that helps any.
                    TomZ
                    And Home Depot has elbows. All you need now is decent flared end pieces.
                    Francis

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                    • #12
                      Takes some practice, but a heat gun and wine bottle can be used to flare pvc pipe.
                      Don't listen to me - I have not sold any $150,000 speakers.

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                      • stephenmarklay
                        stephenmarklay commented
                        Editing a comment
                        I think I will play with this.

                    • #13
                      You can also epoxy the vent so it's flush with the front (or rear) of the cabinet, and then use a roundover bit in the router to create the radius that way. I usually just 'ease' the inside exit of the tube with some coarse sandpaper.

                      TomZ
                      *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                      *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                      *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

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                      • #14
                        Two 1-1/4" pipes have almost the same area as one 1-3/4". 2.45 square inches vs. 2.4 square inches.

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                        • #15
                          If you cannot find the size in pvc, water or drain, try grey electrical conduit.
                          http://techtalk.parts-express.com/fo...khanspires-but
                          http://techtalk.parts-express.com/fo...pico-neo-build
                          http://techtalk.parts-express.com/fo...ensation-build

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