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Hmm, Dayton RS28F - F??? What have we here?

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  • #61
    Re: Hmm, Dayton RS28F - F??? What have we here?

    Originally posted by critofur View Post
    The metal grills are different. The sillk? dome protrudes further and the shape of the protective metal grill thus has to stick out further also.

    I have both, so I could see if the diaphragm fits (I would assume it does).

    You'd have to pop the metal grill off, if you want to switch your RS28 metal dome tweeters over to the soft domes...
    If you don't mind trying to see if it the diaphram would fit (sans faceplate), that'd be great. I happen to have a RS28AS-4 body with a burnt VC (don't ask), so a replacement might be worth considering. If it looks like it will fit, I'll take a look at popping the grill off of my faceplate.
    Dan N.

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    • #62
      Re: Hmm, Dayton RS28F - F??? What have we here?

      Originally posted by critofur View Post
      The metal grills are different. The sillk? dome protrudes further and the shape of the protective metal grill thus has to stick out further also.

      I have both, so I could see if the diaphragm fits (I would assume it does).

      You'd have to pop the metal grill off, if you want to switch your RS28 metal dome tweeters over to the soft domes...
      That appeared to be the case from the photos. I'm curious about how the soft dome measures in the original without the grill. I doubt that anything else is different. The cost to convert would be half the cost of new ones.

      I'm also wonder what the consistency will be with the soft domes. That seems rather difficult for manufacturing.

      dlr
      WinPCD - Windows .NET Passive Crossover Designer

      Dave's Speaker Pages

      Comment


      • #63
        Re: Hmm, Dayton RS28F - F??? What have we here?

        I think the defining issue of 'fit' would be with the style of the faceplates.

        The orig RS28A has a 1-piece assembly, and the whole face/grille lifts off. These have no flat-spot in the grille, and are probably WITH FF.

        The second gen has the flat-spot, and the face is a 2-piece assembly. The mounting flange is separate from the grille-piece. It is possible the grille piece could just be removed, and the diaphragms swapped. Non-FF units.

        These could also be difference in structures between the 3. The first might actually sit forward more at rest, the 2nd gen could sit further back, and the RSilkie could be more forward with a one-piece or 2-piece face.

        I'd like to know how the RSilkie is made as well...
        Later,
        Wolf
        "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
        "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
        "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
        "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

        *InDIYana event website*

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        http://techtalk.parts-express.com/blog.php?u=4102

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        • #64
          Re: Hmm, Dayton RS28F - F??? What have we here?

          Originally posted by Wolf View Post
          I think the defining issue of 'fit' would be with the style of the faceplates.

          The orig RS28A has a 1-piece assembly, and the whole face/grille lifts off. These have no flat-spot in the grille, and are probably WITH FF.

          The second gen has the flat-spot, and the face is a 2-piece assembly. The mounting flange is separate from the grille-piece. It is possible the grille piece could just be removed, and the diaphragms swapped. Non-FF units.

          These could also be difference in structures between the 3. The first might actually sit forward more at rest, the 2nd gen could sit further back, and the RSilkie could be more forward with a one-piece or 2-piece face.

          I'd like to know how the RSilkie is made as well...
          Later,
          Wolf
          I had a beta copy of the original RS28A sent to my by Darren for testing prior to its initial release. It wasn't a one-piece affair. It had a faceplate, a grill cover section and the diaphragm assembly, all separate. My later purchased copies were essentially the same and I see no difference in the pictures of the current offering. You can see the construction from my test page here where the faceplate is already removed:



          It would make no sense for manufacturing costs to make them differently. The assembly line costs should dictate nearly identical construction. It should be possible to remove the grill cover section, then take out the grill. Someone will have to verify this, of course.

          The question on FF is a good one, but it ought to say in the description of each if it is used, although that's no guarantee, of course. Neither description indicates FF is used. This also makes manufacturing sense in that the only thing that should be different is the diaphragm material.

          dlr
          WinPCD - Windows .NET Passive Crossover Designer

          Dave's Speaker Pages

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          • #65
            Re: Hmm, Dayton RS28F - F??? What have we here?

            Originally posted by Wolf View Post
            RSilkie.
            18hz is scary.

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            • #66
              Re: Hmm, Dayton RS28F - F??? What have we here?

              I took the plates off and switched the diaphragms. The motors look identical between the recent "non ferrofluid" RS28As that I have and the RS28Fs that I got. The F also does not have ferrofluid. The voice coils do not look to be of different length or at a different depth.

              I did actually build a box, cut the baffle, and bring it inside to take some measurements - will measure both the A and F to post a comparison. Just something quick and easy for now. Hope to get to that in a bit, but maybe tomorrow.

              And, I discovered an issue with one of my RS28As - the outer copper shorting ring on one of my tweeters was not pushed all the way down when it was manufactured. That tweeter was about 1db more sensitive than the other one, I wonder if it has something to do with the position of the shorting ring? I hope it won't limit x-max of the tweeter by touching the surround.
              "...this is not a subwoofer" - Jeff Bagby ;)

              Comment


              • #67
                Re: Hmm, Dayton RS28F - F??? What have we here?

                Here are measurements of both RS28A and RS28F on an 7" wide baffle, mic close (just under 1 inch away) at low level. They have a 2nd order elec. crossover consisting of a 1uf Cap + .35mH inductor. This crossover makes no sense to me - why is a 1uF letting so much low fr through? Might be something wrong with my measurement setup, will have to check it more thoroughly tomorrow. Anyway, for now, RED is the RS28A and black is the RS28F:

                "...this is not a subwoofer" - Jeff Bagby ;)

                Comment


                • #68
                  Re: Hmm, Dayton RS28F - F??? What have we here?

                  Originally posted by critofur View Post
                  Here are measurements of both RS28A and RS28F on an 7" wide baffle, mic close (just under 1 inch away) at low level. They have a 2nd order elec. crossover consisting of a 1uf Cap + .35mH inductor. This crossover makes no sense to me - why is a 1uF letting so much low fr through? Might be something wrong with my measurement setup, will have to check it more thoroughly tomorrow. Anyway, for now, RED is the RS28A and black is the RS28F:
                  Maybe it's a 10uF and you thought it says 1.0uF...?

                  Comment


                  • #69
                    Re: Hmm, Dayton RS28F - F??? What have we here?

                    Originally posted by envisionelec View Post
                    Maybe it's a 10uF and you thought it says 1.0uF...?
                    No, I've got a box full of these 1uF caps, I've measured a bunch and they're very tight tolerance, I love 'em.

                    They say:

                    CM03
                    nt 1UF +/- 5%
                    200VDC=80M

                    They're more like +/- 1% :D

                    I'll hookup an amp and also use some other mics tomorrow, make sure the sound card settings are all good, measure some woofers also, etc... Oh, and I'll toss together some LspCAD simulations and see what it says too.
                    "...this is not a subwoofer" - Jeff Bagby ;)

                    Comment


                    • #70
                      Re: Hmm, Dayton RS28F - F??? What have we here?

                      Originally posted by critofur View Post
                      Here are measurements of both RS28A and RS28F on an 7" wide baffle, mic close (just under 1 inch away) at low level. They have a 2nd order elec. crossover consisting of a 1uf Cap + .35mH inductor. This crossover makes no sense to me - why is a 1uF letting so much low fr through? Might be something wrong with my measurement setup, will have to check it more thoroughly tomorrow. Anyway, for now, RED is the RS28A and black is the RS28F:

                      It's the one inch distance that's doing it.
                      Click here for Jeff Bagby's Loudspeaker Design Software

                      Comment


                      • #71
                        Re: Don't drink and drive (as in audio speaker driver)

                        Originally posted by Jeff B. View Post
                        It's the one inch distance that's doing it.
                        ...Got to be more careful when doing speaker work late at night - oh - and, after having gone to "Five at Five" which is the local Whole Foods thing where you try five types of wine for $5 :P

                        I'll get the speaker up on a stand and take some higher level measurements from farther away...
                        "...this is not a subwoofer" - Jeff Bagby ;)

                        Comment


                        • #72
                          Re: Hmm, Dayton RS28F - F??? What have we here?

                          I've finished testing these but haven't posted a page yet.

                          You might as well buy a pair now.

                          Same motor as the metal dome RS28A's, double copper sleeve. Very smooth FR, gentle rise, easily correctable.

                          No ferrofluid.

                          Sensitivity ~90-91db/2.83v

                          Excellent distortion performance, on par with the metal dome (didn't directly compare the two yet-but looks usable to 1.3-1.5k)

                          I did not do off axis measurements. Er, I'll let DLR or Zaph do that. Probably not much different than any other 1" dome.
                          audioheuristics isn't around right now...

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                          • #73
                            Re: Hmm, Dayton RS28F - F??? What have we here?

                            Thanks for the effort, Mark!
                            Dan N.

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                            • #74
                              Re: Hmm, Dayton RS28F - F??? What have we here?

                              I've posted my results.

                              http://www.audioheuristics.org/measu...er_group_6.htm
                              audioheuristics isn't around right now...

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                              • #75
                                Re: Hmm, Dayton RS28F - F??? What have we here?

                                Great results!

                                Thanks Mark!

                                Jim

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