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About the shell of the Classix II designed by Paul Carmody

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  • About the shell of the Classix II designed by Paul Carmody

    I got two shell solutions from Paul Carmody's website, but I also got a shell solution they recommended from the parts-express kit webpage. They all work well, right? I prefer the parts-express solution because it is higher and the cabinet depth is smaller. But I think the pre-inverter scheme is too high. So I specially made 3 sketches to compare personal aesthetics.
    I have started to make Paul Carmody's original cabinet plan, and construction is in progress.

    I will build two Classix II, one set for my friend.


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  • #2
    If you do all the math, you'll find very little cubic volume difference in any of the enclosures. I got some BR-1 cabinets on sale dirt-cheap and built some Classic II's in them with great results. Our Mr. Paul C. created a great and forgiving design in the Classic II's and crossed to a sub at 50 Hz or higher, they achieve ear-damaging sound levels with decent distortion levels in smallish rooms, and if you play old vinyl, like early ATCO Stone's pressings, you REALLY appreciate the "relaxed" nature of the reproduction. I have two sets of Classic II's and two sets of the late Lou C's "Veepers" (a super accurate monitor type MT to be used with a sub) so I can play back QUAD sound. There are 15 IPS QUAD R-T-R tapes of the Moody Blues I don't want to listen to on the Veepers.Too many dubs deep and too much IMD.
    Anyway, just put the egg-crate foam inside and all will be well, trust me. They are REALLY hard to screw up! Just get the polarity on the cross-over right to the woofer and tweeter! (Don't ask...YUP, I got one right and one wrong...)

    Comment


    • #3
      What I see in best practice for cabinets from my experience:

      MDF is not very stiff to use as internal bracing
      Extra work rounding the braces Diffraction internally is irrelevant
      Brace is in the center of the panels
      No brace on rear panel
      Tweeter and woofer are symmetrical on baffle
      Tweeter could be closer to woofer. Trimming the tweeter flange works well. ( mod to crossover maybe)
      I don't see rounding the front panel edges.
      PVA glue, going to give issues with the glue lines showing up.
      Drawing does not imply if the port is flared
      2 inch difference in height probably won't make a difference in the crossover BSC, but testing tells the truth.
      I prefer a rear port.

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      • #4
        Just read the write-up. A good lesson for those trying to do a budget build shows it is hard to mitigate basic limitations. Good job it looks like.

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        • #5
          Nice work.

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          • #6
            Originally posted by Whitneyville1 View Post
            If you do all the math, you'll find very little cubic volume difference in any of the enclosures. I got some BR-1 cabinets on sale dirt-cheap and built some Classic II's in them with great results. Our Mr. Paul C. created a great and forgiving design in the Classic II's and crossed to a sub at 50 Hz or higher, they achieve ear-damaging sound levels with decent distortion levels in smallish rooms, and if you play old vinyl, like early ATCO Stone's pressings, you REALLY appreciate the "relaxed" nature of the reproduction. I have two sets of Classic II's and two sets of the late Lou C's "Veepers" (a super accurate monitor type MT to be used with a sub) so I can play back QUAD sound. There are 15 IPS QUAD R-T-R tapes of the Moody Blues I don't want to listen to on the Veepers.Too many dubs deep and too much IMD.
            Anyway, just put the egg-crate foam inside and all will be well, trust me. They are REALLY hard to screw up! Just get the polarity on the cross-over right to the woofer and tweeter! (Don't ask...YUP, I got one right and one wrong...)


            Yes, I did an internal volume calculation and found that their internal volumes are almost identical. So I can choose the size I like with confidence. Regarding the filling, I can only get polyester fiber cotton, I think it should be possible.
            If there is a problem, please point it out to me!

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            • #7
              Originally posted by tvrgeek View Post
              What I see in best practice for cabinets from my experience:

              MDF is not very stiff to use as internal bracing
              Extra work rounding the braces Diffraction internally is irrelevant
              Brace is in the center of the panels
              No brace on rear panel
              Tweeter and woofer are symmetrical on baffle
              Tweeter could be closer to woofer. Trimming the tweeter flange works well. ( mod to crossover maybe)
              I don't see rounding the front panel edges.
              PVA glue, going to give issues with the glue lines showing up.
              Drawing does not imply if the port is flared
              2 inch difference in height probably won't make a difference in the crossover BSC, but testing tells the truth.
              I prefer a rear port.

              Thank you for your comments, I'm still hesitating about the color of the panel. I will advance slowly.

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              • #8
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                I considered a new problem. I placed the OX at the bottom of the cabinet. When the woofer is installed normally, the magnet of the woofer will be closer to the OX coil. Will this affect the sound? Do I need to change the length of the OX line to prevent OX from reaching the wall of the back panel? But prevent the back wall as if the position of the terminal will be affected.
                Hope you guys can give me advice.


                9sheng


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                • #9
                  Very happy to share more photos with everyone!
                  Since May 2020, we have been waiting for parts replenishment, and we can finally place orders on August 12th.

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                  Regrettably, I paid a shipping fee of US$69 and a tariff of US$30.
                  Finally, the accessories were delivered on August 18.

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                  I can't wait to unpack it


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                  Remove or flatten the claws near the edge, so as not to cause cracks on the edge of the MDF, because the screw hole is too close to the edge of the hole, just using 3 claws is enough.

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                  • #10
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                    • #11
                      The crossovers look really nice: you're going to love these speakers!

                      Geoff

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                      • #12
                        Instead of T-nuts, get "hurricane nuts" Made just for MDF.
                        I would not worry about the crossover, though I usually mount mine high behind the tweeter.

                        Good craftsmanship.

                        I put 1/2 x 1/2 reinforcements in the corners so I can use a 1/2 round-over. Front baffle is most important, but I was surprised when I built my current living room monitors that all 12 edges actually effect the sound. I should get around to buying a 3/4 round-over bit.

                        PE sells a poly fill that is not slick like the Walmart pillow stuffing. Does it matter? I do not know. I have a big box of it so I use it. Back in the day, there were "religious" wars between long hair wool, fiberglass, special poly, shredded cotton, or cheap pillow stuffing. Not sure I buy any of the arguments. I measure the Q, stuff, and measure the Q. If I reach my target, then I am happy. ( I try to get my sealed boxes below .6, subs down to .5) Objective measures do not lie as long as you are measuring the right thing. Stuffing a ported box is a bit of a different question. Some prefer foam line and open box. I stuff lightly. Whatever works for you.

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                        • #13
                          Nice craftsmanship on the XO-ers. Very nice. I don't know if you have "Big Lots" clearance stores or the equal in Oz but look for egg-crate bed topper foam at a store (even a Target) either 1 1/2" or 2" will be fine and will probably be cheaper than importing "speaker foam" from the US and trust me (I've used mattress topper in several sets) it works fine. Just wrap the back and sides of the enclosure with the foam, hot glue it or staple it it place, put a chunk on the top and around the sides of the cross-over, cut an "X" for the vent port and go. I splurged for a 27mm (1 1/8" ) round-over router bit for my 3 1/2 HP router to swing for my "Veepers" and I think it works well on my Classix II also, but you do what you can there. Any round-over is better than none on the edges of a speaker. A good hardware store should be able to help you with hurricane nuts. T-nuts and MDF aren't good friends. We ARE NOT CRITICIZING! We are interested in your best success in the first attempt without wasted money, time and materials. Best of luck and enjoy your new speakers, and if we can be of any assistance to you, we're here.

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                          • #14
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