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RS125 - RS28 MTMWW 2.5-way *PIC*

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  • RS125 - RS28 MTMWW 2.5-way *PIC*




    For those who expressed interest in this project, here's a modeled XO and predicted response plots.

    The slight uplift in the lower midrange can be "tuned" by increasing the large inductor to reduce the level just a tad, and the tweeter can be adjusted by simply increasing or decreasing the 2.7 Ohm resistor to drop or raise the tweeter level.
    R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
    Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

    95% of Climate Models Agree: The Observations Must be Wrong
    "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

  • #2
    Thanks Pete! You 'da Man. *NM*



    Comment


    • #3
      These are the unshielded drivers, yes? *NM*



      Comment


      • #4
        Baffle Dimensions?


        What baffle dimensions did you model?

        Thanks. Nice job.

        Comment


        • #5
          Re: Baffle Dimensions?


          > What baffle dimensions did you model?

          > Thanks. Nice job.

          The width of RS125's plus 1 1/2"...

          Comment


          • #6
            Refresh your look at the posted XO *PIC*




            > The width of RS125's plus 1 1/2"...

            Pretty close Rudy. 7 - 8 will be fine.

            I played around with it some more after looking more closely at the impedance plot. Seems a bit low and needlessly so. I also had the resistor drawn at the wrong end of the XO for the tweeter.

            I changed around some values and got the impedance a little more reasonable. The XO region also got a little more phase aligned between woofs and tweet.

            All RS125S, the 8 Ohm woofer.


            R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
            Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

            95% of Climate Models Agree: The Observations Must be Wrong
            "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

            Comment


            • #7
              Re: Refresh your look at the posted XO


              what about using the seas 27TDFC in this 2.5way pete?

              Comment


              • #8
                Updated!!!


                > For those who expressed interest in this
                > project, here's a modeled XO and predicted
                > response plots.

                > The slight uplift in the lower midrange can
                > be "tuned" by increasing the large
                > inductor to reduce the level just a tad, and
                > the tweeter can be adjusted by simply
                > increasing or decreasing the 2.7 Ohm
                > resistor to drop or raise the tweeter level.

                Refresh your browser if you decide to look at it again.

                The original had a schematic error with the resistor on the tweeter circuit at the output instead of the input. That's been corrected.

                Also, changed around a few values in the woofer XO to raise the impedance a little bit.
                R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
                Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

                95% of Climate Models Agree: The Observations Must be Wrong
                "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

                Comment


                • #9
                  It would certainly work


                  > what about using the seas 27TDFC in this
                  > 2.5way pete?

                  The tweeter XO would probably have one less capacitor.

                  I wanted to keep it an all Dayton project though.

                  Let me play around with the TDFC and see what happens.
                  R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
                  Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

                  95% of Climate Models Agree: The Observations Must be Wrong
                  "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

                  Comment


                  • #10
                    TDFC XO


                    > The tweeter XO would probably have one less
                    > capacitor.

                    > I wanted to keep it an all Dayton project
                    > though.

                    > Let me play around with the TDFC and see
                    > what happens.

                    + input to 5uF, then .55mH 20ga to ground, then 6.8 Ohm to the + input of the TDFC.

                    Same woofer circuit.
                    R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
                    Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

                    95% of Climate Models Agree: The Observations Must be Wrong
                    "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

                    Comment


                    • #11
                      Looks like a great project! *NM*



                      Comment


                      • #12
                        Re: Updated!!!


                        Out of curiousity, what are the differences between the two tweeters? (the RS and the Seas). I've never heard either one before and wondered which one would sound better.


                        Comment


                        • #13
                          Re: Updated!!!


                          > Out of curiousity, what are the differences
                          > between the two tweeters? (the RS and the
                          > Seas). I've never heard either one before
                          > and wondered which one would sound better.

                          Jeez, hard call! Personally I do like the Rs28 better. Very neutral. The Seas is very detailed.

                          Comment


                          • #14
                            Re: Refresh your look at the posted XO


                            > Pretty close Rudy. 7 - 8 will be fine.

                            > I played around with it some more after
                            > looking more closely at the impedance plot.
                            > Seems a bit low and needlessly so. I also
                            > had the resistor drawn at the wrong end of
                            > the XO for the tweeter.

                            > I changed around some values and got the
                            > impedance a little more reasonable. The XO
                            > region also got a little more phase aligned
                            > between woofs and tweet.

                            > All RS125S, the 8 Ohm woofer.

                            I'd like four of them please for my computer surround sound whilst I play my DVD's.


                            Comment


                            • #15
                              Tweeter differences...


                              > Out of curiousity, what are the differences
                              > between the two tweeters? (the RS and the
                              > Seas). I've never heard either one before
                              > and wondered which one would sound better.

                              This is just my opinion so others may disagree. The RS tweeter is very smooth, clean and accurate. It doesn't have much shimmer or sparkle at the top end. Percussive instruments that excite frequencies in the mid-treble such as ride cymbals, triangles and tambourines sound very good while higher frequency tones like those from a high-hat cymbal sound more laid back.

                              The 27TDFC is a very good tweeter as well and is the one that I prefer because it just seems to have more "life" to it. The top end has much more shimmer and sparkle and seems to provide a bit more depth to the presentation. It is the opposite in the fact that high-hat cymbals sound great and ride cymbals/triangles/tambourines aren't quite as clear sounding due to less of an emphasis on the fundamental tones and more of an emphasis on higher harmonics.

                              So the main difference is in the top end where the 27TDFC has a lot more life. I find the RS tweeter to be smoother in general. Of course a lot depends on the crossover but some of the fundamental differences cannot be compensated for.
                              RJB Audio Projects
                              http://www.rjbaudio.com

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