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Anarchy and rs28f m/t my first speaker design

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  • #16
    2.75" SEEMs like an awful lot, but it IS driver(s) dependent. What LOOKs like individual driver phase (plots) appears to fall almost exactly on top of each other - which I must say I've never seen that (over such a wide range) before. It would be great if it were true, but I'm suspecting your offset might not be right.

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    • #17
      For a little perspective on your offset, i recently finished a crossover using the rs28f and eclipse w6520r. My z offset was .043. I would not expect the anarchy too be much more if ot all than that. Both drivers are flush mounted as well.
      https://www.facebook.com/Mosaic-Audi...7373763888294/

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      • #18
        I uploaded my files if someone would like like to check the offset that would be great.
        Attached Files

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        • #19
          What is your measurement distance and x and y offsets?
          https://www.facebook.com/Mosaic-Audi...7373763888294/

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          • #20
            measurement distance is 20 inches drivers are centered and the woofer is 6.75 inches below the tweeter.

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            • #21
              And were all measurements taken on the tweeter axis?
              https://www.facebook.com/Mosaic-Audi...7373763888294/

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              • #22
                sorry yes

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                • #23
                  this is what 2.75" looks like in xsim

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                  • #24
                    If you've built it, and the measured result matches your simulation closely then you have the offset right.

                    regarding the reverse null, it doesn't tell you anything that the phase plots don't, its just another way to look at the phase interaction between drivers.

                    it looks like you've reworked your crossover from the initial design. I would expect that you now find it much less bloated in the lower frequencies?
                    "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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                    • #25
                      Post the zma for the drivers, and we can show you some sim options.

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                      • #26
                        here they are
                        Attached Files

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                        • #27
                          Originally posted by joe_bernardi43 View Post
                          I uploaded my files if someone would like like to check the offset that would be great.
                          The woofer frd is not the same as what you are using! The posted frd has a 10dB dip at 350hz. I don't see that in your sim.

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                          • #28
                            that is the raw driver, the one im using has the near field and port blended in. i posted that one as well. which one should i use for finding the offset?

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                            • #29
                              Using the files provided, I found your z-axis offset to be -1.7" on the woofer. For finding the acoustic offset, you would place the mic at the tweeter axis, about 20" is probably okay for distance. Then without moving the mic, measure the tweeter and woofer separately (include phase), then measure both together. Import the separate measurements to your software, enter in the known values for mic location and driver x and y axis offsets. Then adjust the z-axis offset until the simulated combined response matches your measurement. If you've done this correctly in your measurements, then the acoustic offset is -1.7" by my measure. In my simulation, the individual measurement for the woofer appears to be at slightly higher amplitude than the combined response, which makes me question the measurement method a bit. Click image for larger version

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                              As I said, since you have the mic and it appears that you've already constructed a crossover, verifying your offset should be as easy as taking measurements and verifying them against your simulation.

                              In your post above (#23) where you are trying to show the acoustic offset measurement, I have to wonder why this chart is so smoothed, as the smoothing is not evident in your measurements. If there is any smoothing applied by xsim, you should disable it.
                              "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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                              • #30
                                The file you posted where you blended near and far field measurements does not include phase. You'll want to extract min phase for this file
                                "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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