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Peerless SVS buyout aluminum woofer and SB26 STAC - the SVS STAC

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  • #16
    Originally posted by Mike220 View Post
    Here is what i used for approx 2k xo point. Used a different woofer that was recessed far. If u have the parts on hand its worth a shot. Rev polarity on the tweeter.
    Mike thanks for sharing this. I did give your schematic a run in PCD but had a rising tweeter response that didn't work very well with my measurements.

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    • #17
      I decided on a slight smiley face eq because i used a 4" woofer. To me it made them sound like a large speaker. My sb26stacs were a few years old at this point perhaps there was a change. I believe if you increase the last resistor value (10-15ohm) it will taper of the the rising portion. I did try to level the tweeter out but to me (and you can try this when you mock up your xover) to swap a few parts and see what the difference is.

      If your ordering parts i would try to get a few values above and below your caps (npe) and the resistors are cheap so buy quite a few of those in varied ranges a few above and below your needs. This way you can tinker and take measurement to compare to the model and see how close it is.
      My Build Thread's
      Carrera's / Finalist TL's / Speedster TMM's / Speedster MTM Center / Overnight Sensation Surrounds

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      • #18
        Can someone share how I would put a notch on the woofer peak? I have tried a few times with the notch item (under the series tab) but I can't seem to get it to drop the resonance without altering other aspects of the response or having a sharp spike.

        Here is the peak at 6khz and 25db down. The raw woofer measurements I took included off-axis response, and this peak doesn't drop at all even up to 30 deg off axis, so I'd like to drop it further than I've got it.

        Attached Files

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        • #19
          Add a .22 to .47uf cap in parallel with the woofers inductor.
          https://www.facebook.com/Mosaic-Audi...7373763888294/

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          • #20
            (Ignore this post. I deleted stuff that would only have confused matters)
            Last edited by Dirk; 11-08-2017, 03:22 PM.
            nothing can stop me now

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            • #21
              In PCD I'll add a RLC network in series before the filter, then 0 the woofer inductor and add that value to the RLC network. Then add your C value for the notch, and enter 99999 for the resistor.
              Electronics engineer, woofer enthusiast, and musician.
              Wogg Music

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              • #22
                Originally posted by Dirk View Post


                I can't recall if the PCD allows solitary parallel caps. If not, I would model it in the PCD by including a Zobel with Chuck's cap value and a 0 ohm resistor.

                From an electrical point of view, the parallel cap will cause the apparent impedance of the woofer to become zero (or near zero) at high frequencies. This makes the 2nd order LP SUPER effective at shutting down woofer's high frequency response.
                In PCD, set the woofer inductor to zero. Go to filter before cross over and click up to the lcr circuit. Add in the woofer inductor value, the cap value, and 9999999999 as the resistor. I wouldn't bother with a zobel. If you have a spike at the knee, add a resistor in series with the cap. This is a damped 2nd order network.
                https://www.facebook.com/Mosaic-Audi...7373763888294/

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                • #23
                  Originally posted by wogg View Post
                  In PCD I'll add a RLC network in series before the filter, then 0 the woofer inductor and add that value to the RLC network. Then add your C value for the notch, and enter 99999 for the resistor.
                  ^ This is how i was taught to do it by Craig S.
                  My Build Thread's
                  Carrera's / Finalist TL's / Speedster TMM's / Speedster MTM Center / Overnight Sensation Surrounds

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                  • #24
                    I failed reading comprehension this morning. I misread "with the woofer's inductor" as "with the woofer". That makes way more sense. I'll see myself out.
                    nothing can stop me now

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                    • #25
                      Thanks for the detailed explanation all. Here's the result with a bit more tweaking. I think it's getting there!

                      Scott
                      Attached Files

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                      • #26
                        Here are some pics of the drivers and the speaker in an almost complete state (sans crossover).

                        Attached Files

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                        • #27
                          Looks good!
                          My Build Thread's
                          Carrera's / Finalist TL's / Speedster TMM's / Speedster MTM Center / Overnight Sensation Surrounds

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                          • #28
                            Yes it does! Nice work!
                            https://www.facebook.com/Mosaic-Audi...7373763888294/

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                            • #29
                              I'd try a notch on the woofer at about 1.2k. Just knock it down about 4dB with a sharp notch. Then rework the cap and coil values for a smoother roll off with about the same x-over frequency. After doing this, I suspect that the dip at 800hz will fill in a bit.

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                              • #30
                                Ok I tried a second Parallel notch RLC in the after crossover tab with 0.45 mH inductor, 50 uF cap, and 1.5ohm resistor which dropped the peak a bit, but also dropped the 300-1000 level and didn't flatten out the 800hz dip. Any suggestions?

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