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Dayton Audio RST28F-4 W/ SEOS Wave Guide.

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  • Dayton Audio RST28F-4 W/ SEOS Wave Guide.

    I have modded a SEOS WG to fit the new RTS, I used a old chamfer to bore about 1/8" into the
    back of the "throat". I am wondering if this will have any ill effects on the performance.
    I am also not sure how the dome diffuser will function in the guide. It will be fun finding out!

    Measurements comparing the non modded horn mounted on the old RS Tweet,
    coming soon! Click image for larger version

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    Guess xmax's age.

    My guess: 15. His grammar is passable. His trolling is good.

  • #2
    If the chamfer acts weird, since the guide is already ruined you could try running the chamfer bit all the way through, opening the throat entirely instead of just enough to clear the screen
    Projects:

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    References: http://techtalk.parts-express.com/sh...-My-References
    Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

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    • #3
      It does not seem to cause any problems, this is the RST vs the RS (with the non-modded WG) with and without a 6.8uf cap. Click image for larger version

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      Guess xmax's age.

      My guess: 15. His grammar is passable. His trolling is good.

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      • #4
        Dang! that is mighty impressive with just a 6.8uF cap. Lookin good!
        Voxel Down Firing with Dayton SA70
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        SevenSixTwo - InDIYana 2018 Coax

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        • #5
          Even if you consider the change in response, somewhere above 2kHz all the distortion products have increased when the cap is added. Assuming you haven't touched the volume knob on the amp between measurements, the results are questionable, but that's nothing new. I guess it's not just resistors that add distortion
          "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
          exactly a Fc 3K for both drivers, anybody can do it." -Xmax

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          • #6
            Perhaps you could offer us some non questionable data? Any component can directly or indirectly cause distortion
            if used to do so.
            Guess xmax's age.

            My guess: 15. His grammar is passable. His trolling is good.

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            • #7
              I can only provide you a list of people who like my speakers so you know I'm legit ;). I'm actually in the middle of a big move, so I won't be measuring anything for at least a month, probably closer to 2 months, but if you are confident that your cap is the source of that much harmonics, I'd toss them in the bin if I were you. Of course, with distortion products that large, you could run the electrical signal at the speaker back to your measurement equipment to run the same HD test of only the electrical signal, no mic needed, just a voltage divider to bring the signal down to soundcard input level. You are looking at nearly 0.5-1% THD here, so it should be well discernable above the noise floor compared to the 0.001% THD+N from the amp.
              "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
              exactly a Fc 3K for both drivers, anybody can do it." -Xmax

              Comment


              • #8
                I've gotta agree with dcibel here. In your top measurement, the distortion products are about 55dB below the signal. After the cap is added, there's approximately 10dB more distortion across the band. That is worth investigating.
                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.

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                • #9
                  This test was not about distortion, only the new vs old RS tweets with the SEOS WG.
                  Members on this forum have been asking about using the new tweeter with the WG
                  I did not optimize the test for low distortion. I only included the 6.8uf cap data for fun.
                  I usually compare one driver to another as a point of reference or the factory
                  curves like my Viawave measurements to insure accuracy.
                  I have provided measurements for plenty of drivers under better test conditions
                  This thread has a few
                  http://techtalk.parts-express.com/fo...erless-tweeter
                  Guess xmax's age.

                  My guess: 15. His grammar is passable. His trolling is good.

                  Comment


                  • #10
                    Originally posted by Pete Schumacher View Post
                    I've gotta agree with dcibel here. In your top measurement, the distortion products are about 55dB below the signal. After the cap is added, there's approximately 10dB more distortion across the band. That is worth investigating.
                    No problem Pete I will test them again tomorrow under better conditions.
                    Guess xmax's age.

                    My guess: 15. His grammar is passable. His trolling is good.

                    Comment


                    • #11
                      Originally posted by xmax View Post
                      This test was not about distortion, only the new vs old RS tweets with the SEOS WG.
                      Members on this forum have been asking about using the new tweeter with the WG
                      And for that data, great job! Looks like that guide was made for that tweeter . . . (it was actually). And your mod seems to have had no adverse effect.
                      Amazing how flat that overall response is with just a single cap.
                      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.

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                      • #12
                        I guess I forgot to post these pics, you can barley see the "diffuser" under the new tweets grill.
                        Next I want to try these (or new ones) with the new Peerless TX. Click image for larger version

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                        Guess xmax's age.

                        My guess: 15. His grammar is passable. His trolling is good.

                        Comment


                        • #13
                          Nice work xmax.

                          Good caps do not add (much if any) distortion.
                          Look at the top curve, the fundamental at 10K is -2dB, look at the bottom it is +5dB the
                          level changed between runs. It is that simple 7 more dB passband output on the lower curve.

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                          • #14
                            Exactly, I also think there was some background noise and the gain staging was not ideal.
                            Guess xmax's age.

                            My guess: 15. His grammar is passable. His trolling is good.

                            Comment


                            • #15
                              Originally posted by Pete Basel View Post
                              Nice work xmax.

                              Good caps do not add (much if any) distortion.
                              Look at the top curve, the fundamental at 10K is -2dB, look at the bottom it is +5dB the
                              level changed between runs. It is that simple 7 more dB passband output on the lower curve.
                              That's correct about the distortion products generated by the caps, increasing 10-20dB is unheard of, but I'm sure xmax is aware of that.

                              I'm not experienced with fuzzmeasure, so ive no idea how it decides what is 0dB, but if the amp gain wasn't changes as I posted above, and what a sane person would do when making measurements meants to be compared, then the output level is actually descreased in the lower tweeter band, the higher frequencies at roughly the same level. The problem in making th comparison easy, is that fuzzmeasure doesn't normalize the response, so you have to do some math at each frequency to determine the actual level of harmonic from the fundamental.

                              Anyway, the good news for most here is that the seos waveguide can be easily modified for use with the RST.
                              "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
                              exactly a Fc 3K for both drivers, anybody can do it." -Xmax

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