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Proven design - same volume different design

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  • Proven design - same volume different design

    I am about to build a pair of Speedsters and would like to change the cabinet measurements and overall design due to 1) lack of space 2) presonal preferences 3) marginal better imaging with curved baffle (I know, I know there is a lot of controversy on this point) . If the information I gathered until now is correct, 2 aspects of the speaker original cabinet design must remain the same: 1) volume 2) speaker position on the baffle respective to baffle top.

    Considering this information I designed a first version of the cabinet which has no flat surface - except top and bottom. It is more ore less egg-shape, including the baffle which is also curved. The cabinet is not as deep as the original design but maintains the same volume.

    Will the speaker maintain its qualities Or most of them if I build it explained above and keep speaker position relative to top of the baffle and volume the same as in the original design but change the rest of the cabinet?


  • #2
    We need pics. I do anyway.


    • #3
      2) speaker position on baffle
      this is not just relative to the top, but same baffle width, distance to sides and center to center distance between the drivers.


      • #4
        I read on another forum that speaker position relative to the bottom was not important and you could always make a taller cabinet. So that is not true? I will keep all other speakers spacing the same as in the original design. Let assume I do keep the same baffle design as the original and only change cabinet form and keep the same volume. Would that work? djg I will post some pictures as soon as I have positioned the speakers. I am using Fusion 360 and I am not a CAD expert, it takes some time to figure things out. Envoyé de mon CLT-L09 en utilisant Tapatalk


        • #5
          I just found the Reddit thread I was referring to: Reading this anew it seems that baffle size is important if it was taken into consideration in the crossover design. Given his reputation, I would think that Paul Carmody did model the crossover with baffle step reduction and so baffle should be left untouched. What do you guys think?


          • #6
            Taller is fine, as that won't effect baffle step. You're trying to keep the baffle step, the driver to driver timing, and the edge diffraction in line with the original design in order for the crossover to still be valid. So the above guidelines remain:
            Same driver positions from top and each other
            Same baffle width

            Of your proposed plans, the most concerning would be the curvature of the baffle. That will change the center to center and Z axis offset of the drivers and could have a significant effect on the crossover. Diffraction changes with round over on the baffle will have a small and likely not noticeable effect.
            Electronics engineer, woofer enthusiast, and musician.
            Wogg Music
            Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat, SuperNova Minimus


            • #7
              That curved baffle will also likely shelve-up the treble. Be aware this could make them very bright.

              "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
              "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
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              • #8
                Thanks a lot for your thoughts, wogg and Wolf. I should have explained that I am planning a translam, so curvature would only be on the x / z plan. Not sure but I think that would reduce positioning changes to the minimum. Of more concern is the point Wolf raised about them being brighter. I might leave the baffle untouched. Will keep you posted.


                • #9
                  As long as the internal volume is the same, the bass response will sound the same... so that's good.

                  Now, a radically different baffle will affect diffraction--I have no idea how much. Although chances are as long as the drivers are in the same Z axis, they should sound pretty close to the original. Basically, if you move the Z axis of the tweeter or the woofer, you are changing the listening angle. I hope I'm making sense.
                  Isn't it about time we started answering rhetorical questions?

                  Paul Carmody's DIY Audio Projects
                  Twitter: @undefinition1


                  • #10
                    Thanks for the additional thoughts and for the original design, Paul. In the current design the curvature is also minimal and the should further reduce concerns about diffraction. I will post some pictures of the drawing soon to give you a better idea of the changes. Next is slot or port design, I am not sure how either will fit with the shallower cabinet depth.


                    • #11
                      Some screenshots to illustrate. I took measurement from another design so hopefully they're accurate. The curvature of the baffle is clearly visible and in my opinion quite minimal. Height and final shape will be modified via trial and error until the final volume is achieved (5.5L I need to check again).

                      I forgot to mention that I am also playing with the idea to create an anechoic profile inside the cabinet (the triangles inside the profile on the last pic). The overall effort is minimal as I am planning a translam with profile laser cut. Is that a good idea? Will it bring anything at all ?


                      • #12
                        So mounting flat surface drivers to a curved baffle leaves either the edges protruding or the middles sunken into the baffle. I don't think that would look very good, but it's your project and vision. I have no idea what effects on sound would arise.