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RS180S-8 & RS180-4, interchangeable in the same MLTL?

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  • RS180S-8 & RS180-4, interchangeable in the same MLTL?

    I have two RS180S-8 woofers and I'm considering building Jon Marsh's Modula MT, but in a MLTL. Paul K uses the RS180-4 (differ from mine in that they are unshielded and 4 ohm) in his Brillante MLTL. Both cabinets are 9" wide. Can I build the Modula MT in Paul's MLTL without adjustments to the line, or, for optimization for the RS180S-8, would some changes be recommended? I have long admired/appreciated/respected the bass qualities that Paul achieves with his MLTLs. Thanks in advance for your advice.

    David

  • #2
    From my experience modelling transmission lines, I would say the existing design wouldn't work, but a new very similar design could work. I'd send Paul K a message directly.

    Comment


    • #3
      David, if you provide me with T/S values for the RS180S-8 you believe are reasonably representative of your drivers (or actual T/S measurements for your drivers) I can quickly plug them into the Brillante's ML-TL design to see what's what. I'll need: fs, Re, Le, Bl, Sd, Vas, Qes and Qms (if you have either Vas or Bl, along with the other values, I can accurately calculate either Bl or Vas).
      Paul

      Originally posted by dstmbgh View Post
      I have two RS180S-8 woofers and I'm considering building Jon Marsh's Modula MT, but in a MLTL. Paul K uses the RS180-4 (differ from mine in that they are unshielded and 4 ohm) in his Brillante MLTL. Both cabinets are 9" wide. Can I build the Modula MT in Paul's MLTL without adjustments to the line, or, for optimization for the RS180S-8, would some changes be recommended? I have long admired/appreciated/respected the bass qualities that Paul achieves with his MLTLs. Thanks in advance for your advice.

      David

      Comment


      • #4
        [QUOTE=Paul K.;n1398763]David, if you provide me with T/S values for the RS180S-8 you believe are reasonably representative of your drivers (or actual T/S measurements for your drivers) I can quickly plug them into the Brillante's ML-TL design to see what's what. I'll need: fs, Re, Le, Bl, Sd, Vas, Qes and Qms (if you have either Vas or Bl, along with the other values, I can accurately calculate either Bl or Vas).
        Paul

        Thank you so much, Paul, for your offer to help. I don't have the equipment to measure my drivers, but I found the following:

        from Zaph:



        from Paul Carmody:



        and finally, Dayton's data. I noticed that in reply to dustinbagbey, both jhollander and bullittstang said that their drivers "measured very close" to the manufacture's specs.

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        • #5
          Actually the RS180-8 will work in the Brillante's ML-TL with a minor change in the length of the mass-loading port. I've attached a comparison of the predicted system bass responses showing first that of the RS180-4 as I built the Brillante. Following is that for the RS180-8 using Zaph's T/S measurement and without any change to the ML-TL. The third graph is the also for Zaph's measurements but with the original port length of 4" shortened to 2.5". The last shows the results using Paul Carmody's measurements, also with the port shortened to 2.5".
          Paul
          Brillante driver comparisons.doc
          Attached Files

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          • #6
            Paul, that is so very helpful. You are a scholar and a gentleman! I look forward to building these, and will certainly post my results, but it will be a bit before I can start as I just recently moved and don't have my woodshop set up yet. Thanks again, Paul, for your help, and please know how impressed I've been with both hearing and seeing your work at some of the InDIYana get-togethers in Fort Wayne.

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            • #7
              You're quite welcome, David, and I really appreciate your compliments on my work. Likely later today I'll set up the model again and see how your driver performs in it using PE's published specs; I expect it will be similar to the other 3 modeling results.
              Paul

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              • #8
                Okay, I modeled the Brillante's ML-TL for the RS180S-8 using PE's published specs David linked and with the port shortened to 2.5", then added the graph showing the predicted system bass response to the previous 4 graphs.
                Paul
                Attached Files

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