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DIII refried (RS28F upgrade)

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  • DIII refried (RS28F upgrade)

    This all started when a PE forum member suggested "upgrading" the DIII with the RS28F tweeter. Reason being, this particular tweeter can cross so ridiculously low (1000 Hz), that it could possibly relieve the DC160 from its struggle to play the upper midrange.

    Well, while I had a pair of RS28F on-hand, I decided to try it. I measured the drivers in my original DIII cabinet (my first successful DIY build ever ), and re-did the crossover. To my surprise, this experiment did work; the midrange was much-improved! As an added bonus, the speaker was now usable in a vertical or horizontal orientation--within reason. With the original driver spacing, I can keep a relatively flat response within +/- 40 degrees. If one were to place the drivers closer, this would probably allow for a larger listening axis.

    Is it the last word in high resolution? No, of course not. But it does what it's supposed to: it keeps the amazing bass extension of the DIII, but allows for a much more refined midrange. Plus, the fact that it can be used vertically or horizontally makes it pretty versatile.

    If you own a pair of DIII and want to "upgrade" them, the challenge will be how to retrofit the RS28F into the slightly larger hole for the original DC28F.
    If you were to build a pair from scratch, then you would just build the DIII cabinet to Wayne's specs.
    Attached Files
    Isn't it about time we started answering rhetorical questions?

    Paul Carmody's DIY Audio Projects
    Twitter: @undefinition1

  • #2
    Re: DIII refried (RS28F upgrade)

    Paul,

    Just curious - why the resistor 'before' the cap on the tweeter?

    Comment


    • #3
      Re: DIII refried (RS28F upgrade)

      Thanks for this work Paul. I have 2 pair of these which will have new cabinets this spring hopefully ( I live in eastern Iowa ) I will be moving the woofers closer to the tweeter as that look is much more appealing to the wife and we all know how much that can matter.....:rolleyes:

      Again thanks and this time they won't stay MDF.

      Comment


      • #4
        Re: DIII refried (RS28F upgrade)

        Originally posted by martyh View Post
        Paul,

        Just curious - why the resistor 'before' the cap on the tweeter?
        I do that, too. In modeling, it doesn't alter the "knee" as much on the tweeter curve. Also, it doesn't seem to cause as much erratic behavior in the upper octave.
        Don't listen to me - I have not sold any $150,000 speakers.

        Comment


        • #5
          Re: DIII refried (RS28F upgrade)

          Paul, can you bring those to InDIYana (space permitting)? Super easy XO, inexpensive, etc. they should be a real winner for a higher-end starter kit ...next stop the BR1?????

          Cheers / Robert

          Comment


          • #6
            Re: DIII refried (RS28F upgrade)

            Paul,
            While I have not had all the complaints about the DIII as some others I thank you for an opportunity to super charge them a bit. I hope that some day I will be able to do what you did with this project. You remind me of the Wizard of Oz. Is your house green? Are you the great and powerful Carmody?

            Howard

            Comment


            • #7
              Re: DIII refried (RS28F upgrade)

              Paul,

              Thanks so much...how fortuitous that they are on DOD today...Yeeha! I'll be orderin' me some.

              Kevin

              Comment


              • #8
                Re: DIII refried (RS28F upgrade)

                They were my first also, and they were taken by my first born. So thanks for doing this. I'll see if he wants to give up some money for the upgrade or if he'll wait for me to buy them. It could be his going away present. :D
                Tim

                Comment


                • #9
                  Re: DIII refried (RS28F upgrade)

                  I ordered the RS28F x 2 and the crossover parts. I'll let you know how it goes.

                  I will re-purpose the silkies by replacing some EPI 100 tweeters (one is punctured) along with the DIII tweeter crossover which I believe is at 1800...same as the EPI tweeter. Not sure if I"ll have to remove or add padding for the silkie, but it should work ok as they are garage speakers.

                  Wish me luck...

                  Kevin

                  Comment


                  • #10
                    Re: DIII refried (RS28F upgrade)

                    Paul, Thanks loads! Just what I was looking for. Are the coils all 16 or 18 awg or a combination?

                    Comment


                    • #11
                      Re: DIII refried (RS28F upgrade)

                      Originally posted by jclemmojoe View Post
                      Paul, Thanks loads! Just what I was looking for. Are the coils all 16 or 18 awg or a combination?
                      I'd suggest ~18 awg for L2, and 18-20 awg for L1.

                      Enjoy!
                      Isn't it about time we started answering rhetorical questions?

                      Paul Carmody's DIY Audio Projects
                      Twitter: @undefinition1

                      Comment


                      • #12
                        Re: DIII refried (RS28F upgrade)

                        You're the greatest!!!!

                        Gone!

                        Comment


                        • #13
                          Re: DIII refried (RS28F upgrade)

                          Paul,

                          The DIIIs were one of my 1st builds, too. My son still enjoys them but is interested in the upgrade.

                          Did you salvage parts from the original xovers?
                          The originals included 6.8 and 9.2 caps that could be paralleled for a total of 16mf. That's within 10% of your spec'd 15uf. Close enough?

                          The original 2.7uf and 47uf can be paralleled to make your 50uf C2.

                          That leaves:
                          1 and 3.7ohm resistors 2.50
                          .25 and 3.0 mH inductors 22.75
                          RS28F-4 tweeter 49.75 (DOTD is over:()

                          $75 total times 2 = $150 to upgrade two speakers.


                          Whoa....that's what Wayne listed as the total parts price of the originals way back when! Ummmmmm.....how much do the overnight sensation MTMs cost?:D

                          Marvin

                          Comment


                          • #14
                            Re: DIII refried (RS28F upgrade)

                            Originally posted by marvin View Post
                            Paul,

                            The DIIIs were one of my 1st builds, too. My son still enjoys them but is interested in the upgrade.

                            Did you salvage parts from the original xovers?
                            The originals included 6.8 and 9.2 caps that could be paralleled for a total of 16mf. That's within 10% of your spec'd 15uf. Close enough?

                            The original 2.7uf and 47uf can be paralleled to make your 50uf C2.

                            That leaves:
                            1 and 3.7ohm resistors 2.50
                            .25 and 3.0 mH inductors 22.75
                            RS28F-4 tweeter 49.75 (DOTD is over:()
                            That's good thinking to salvage the parts from the original. Mine are all permanently glued down by GOOP (note: I use zip ties now. At least that way I can remove a crossover component if the future if I ever want to)

                            $75 total times 2 = $150 to upgrade two speakers.

                            Whoa....that's what Wayne listed as the total parts price of the originals way back when! Ummmmmm.....how much do the overnight sensation MTMs cost?:D
                            Yeah, you're totally right. It's a bit of a pricey upgrade, when compared to the cost of the original parts. I kind of knew that from the outset--but the whole DIII Refried was really more of an experiment. I will say that the Refried version does fix the weak mids of the original. The added bonus is that the speaker sounds the same whether vertically or horizontally oriented.
                            Isn't it about time we started answering rhetorical questions?

                            Paul Carmody's DIY Audio Projects
                            Twitter: @undefinition1

                            Comment


                            • #15
                              Re: DIII refried (RS28F upgrade)

                              Can anyone comment more on these by chance? I'm seriously considering these for an LCR. I'm a little nervous about the tweeters power handling with such a low crossover.

                              Comment

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