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The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

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  • The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

    So, what started out as a quick little writeup about crossovers...turned into a bit more...about 60 pages more.

    The DIYRM-A is a Do-It-Yourself Reference Monitor....much along the lines of an LS3/5a. Can be used a bit more broadly and works better with modern music.

    The writeup can be found at:

    https://goo.gl/XboqRW



    The document covers:
    Introduction
    Design Goals
    Driver Selection
    Enclosure Design and Construction
    Design Measurements
    Crossover Design
    Listening Notes
    Crossover Power Handling Testing
    Conclusion
    They are excellent for a variety of applications from near-field monitoring, two channel stereo where space is a concern and surround sound applications, again where space prevents the use of larger designs.

    I hope you enjoy.

    Scott "SpeakerScott" Hinson
    Last edited by SpeakerScott; 05-04-2015, 09:44 PM.
    DIYRM-A Thread, a 60 page speaker design guide
    Tumblr
    Direct link to DIYRM-A/B Updated PDF

  • #2
    Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

    Thank you for sharing.

    Comment


    • #3
      Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

      Originally posted by djg View Post
      Thank you for sharing.
      No problem. You are welcome. My wife is the professional writer, as an engineer I try not to stink at it. Any suggestions for additional content or technical information let me know. I'm in the process of building a second pair, so there is an opportunity for changes or pictures mid-assembly that I didn't take before.

      Scott
      DIYRM-A Thread, a 60 page speaker design guide
      Tumblr
      Direct link to DIYRM-A/B Updated PDF

      Comment


      • #4
        Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

        Nice work, and I just read almost all of it.

        Comment


        • #5
          Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

          As an engineer you should be very able to write with clarity and thoroughness. That old adage, "6 munths ago I culdn't even spel unginer, now I are one", shouldn't automatically apply just because you are technically educated as opposed to having majored in liberal arts. No need to sell yourself or your education short.
          Paul

          Originally posted by SpeakerScott View Post
          No problem. You are welcome. My wife is the professional writer, as an engineer I try not to stink at it. Any suggestions for additional content or technical information let me know. I'm in the process of building a second pair, so there is an opportunity for changes or pictures mid-assembly that I didn't take before.

          Scott

          Comment


          • #6
            Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

            There's a "sticky" thread of designs at the top of page 1. You can post this there.

            Comment


            • #7
              Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

              These are an interesting contrast to the Continuum's

              Comment


              • #8
                Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

                Nice write-up. I can see you put a lot of effort into it. I probably spent more time researching the LS3/5a than any other speaker ever. It took me a little while to figure out what gave it its midrange quality because they don't come out and say it, but once I figured it out it wasn't hard to duplicate it. I have a big zip file filled with info on the BBC LS3 /5a, if you want to download it let me know.

                One thing from your write-up that I want to clarify : you talk about LS3/5a, Spica, and Dunlavy speakers using diffraction foam. However, none of these used foam, which is actually pretty poor at controlling diffraction. They all use thick felt for diffraction control. I experimented with felt on the Continuum but in the end opted to not use it.

                Nice job on the speaker.
                Jeff
                Click here for Jeff Bagby's Loudspeaker Design Software

                Comment


                • #9
                  Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

                  Originally posted by Jeff B. View Post
                  . However, none of these used foam, which is actually pretty poor at controlling diffraction. They all use thick felt for diffraction control. I experimented with felt on the Continuum but in the end opted to not use it.

                  Nice job on the speaker.
                  Jeff
                  Didn't they use wool felt? Very dense I believe.
                  -Dan
                  Mandolin Curved Cabinet Floorstanding; Dayton Reference 18" sealed Subwoofer; Sealed 12" Dayton Reference Subwoofer ; Overnight Sensation builds

                  Comment


                  • #10
                    Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

                    I'm curious why the crossover requires ~19 parts? Was this required to achieve what you wanted?

                    Comment


                    • #11
                      Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

                      Originally posted by Jeff B. View Post
                      Nice write-up. I can see you put a lot of effort into it. I probably spent more time researching the LS3/5a than any other speaker ever. It took me a little while to figure out what gave it its midrange quality because they don't come out and say it, but once I figured it out it wasn't hard to duplicate it. I have a big zip file filled with info on the BBC LS3 /5a, if you want to download it let me know.

                      One thing from your write-up that I want to clarify : you talk about LS3/5a, Spica, and Dunlavy speakers using diffraction foam. However, none of these used foam, which is actually pretty poor at controlling diffraction. They all use thick felt for diffraction control. I experimented with felt on the Continuum but in the end opted to not use it.

                      Nice job on the speaker.
                      Jeff
                      Good point on the foam/felt for the mentioned speakers. I'll add that to my correction/addition/change list for the document.

                      I've tried many foams and felts over the years, and performance has always varied wildly between manufacturer, density and material. In this case a builder will have a slew of extra foam lying around from the 12"x24" sheet needed for the grills, so that's the easiest and it works fairly well.

                      Thank you for the offer on the LS3/5a material, I've probably got more than I need as it is. ;-) Back to my second set of Synergy Horns...and planning for a DIYRM-B.

                      Scott
                      DIYRM-A Thread, a 60 page speaker design guide
                      Tumblr
                      Direct link to DIYRM-A/B Updated PDF

                      Comment


                      • #12
                        Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

                        Very nice write up
                        Thank you for sharing it

                        i'm wondering
                        do you have to add woofer mass?
                        can I use blutack instead wire ?

                        How it's compared to the original ls3/5s?
                        my impression of The original ls3/5a , human voice is very good and i like the chestyness of male voice but the high note was quite shrill

                        Have you listtened to jeff's continuum?

                        Comment


                        • #13
                          Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

                          Originally posted by johnhenry View Post
                          Very nice write up
                          Thank you for sharing it

                          i'm wondering
                          do you have to add woofer mass?
                          can I use blutack instead wire ?

                          How it's compared to the original ls3/5s?
                          my impression of The original ls3/5a , human voice is very good and i like the chestyness of male voice but the high note was quite shrill

                          Have you listtened to jeff's continuum?
                          johnhenry,

                          Yes, you have to add woofer mass in order for the speaker to have the correct spectral balance. It will be midrange heavy and bass shy if the mass isn't added.

                          I would say it doesn't have any of what one Stereophile reviewer called "spitch" to the treble. I would call that sound "edginess" and it often drives me to turn a speaker down on songs that should scream turn it it, especially after a bit of time in the listening session. (At the beginning it can often be confused for detail, but detail doesn't lead to fatigue...edginess does.) The DIYRM-A is thankfully free of that coloration. Male voices are excellent.

                          I doubt blue-tack would work, it doesn't have the density that copper does, the ring of material would be too wide and get on the cone surface far enough out to impact frequency response and the crossover would not be right.

                          Scott
                          DIYRM-A Thread, a 60 page speaker design guide
                          Tumblr
                          Direct link to DIYRM-A/B Updated PDF

                          Comment


                          • #14
                            Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

                            Originally posted by SpeakerScott View Post
                            johnhenry,

                            Yes, you have to add woofer mass in order for the speaker to have the correct spectral balance. It will be midrange heavy and bass shy if the mass isn't added.


                            Scott
                            Adding mass is an unusual solution for this issue, why not just use larger inductors in the low pass crossover? The inductors you chose are smaller than typical for a speaker this size anyway.
                            Click here for Jeff Bagby's Loudspeaker Design Software

                            Comment


                            • #15
                              Re: The DIYRM-A, Two way Dayton RS150P and RS28 Tweeter-60 Page Design Guide

                              Originally posted by Jeff B. View Post
                              Adding mass is an unusual solution for this issue, why not just use larger inductors in the low pass crossover? The inductors you chose are smaller than typical for a speaker this size anyway.
                              Jeff,

                              A minor reason was cost, I was really trying to keep the cost of the system lower. Inductors are very expensive compared to super-glue and a few inches of wire.

                              A major reason was space, as you know it's tough to get that much stuff in a box that small. I had concerns about the inductor fitting behind the woofer/tweeter depending on size and shape.

                              The 1.5mH inductor on the woofer circuit provides the only low pass inductance. The other two .2mH inductors are in phase/shaping networks.

                              Scott
                              DIYRM-A Thread, a 60 page speaker design guide
                              Tumblr
                              Direct link to DIYRM-A/B Updated PDF

                              Comment

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