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Morel CAT308 with RS180S in Amiga box

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  • Morel CAT308 with RS180S in Amiga box

    First time speaker builder here. Have been looking to do something for a while and finally have wife's approval to spend the money (most important point) and found a speaker that I would like to try as my first attempt. Something not too far off the beaten path of a proven design but with some modifications to personalize and make it challenging and a learning experience.

    So looking to use the Morel CAT 308 tweeter and the Dayton Audio RS180S woofer in the Paul Carmody Amiga box. Crossover is a modified version of what TOID and Wolf put together last year for RST28F/RS180S which also would work in the Amiga box. Goals:

    Crossover around 2K
    Keep RS180S cone breakup to a minimum
    Use Parts Express Amiga kit and purchase whatever else I need (like the Morel tweeters)
    Learn something and have some fun

    Crossover:

    Click image for larger version

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    SPL

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    Please let me know what you think.
    Thanks.
    John

  • #2
    Welcome to the hobby!

    My first thought was to ask why you wouldn't just build the Amiga as is, but you've answered that: however, this is your first project and you (collectively) want to be happy with the result. There is some risk in what you're proposing, if you don't like the result.

    I take it you're thinking of buying the whole kit to get the cabinet and woofers? Perhaps ask PE nicely if they would consider selling you just those items, if you buy the kit you will have leftover tweeters and crossover parts; although if your mods don't work out, you could build the Amigas and use the 308s for another project.

    The 308 and DX25 have very similar stated dimensions, so the 308s should (should!) fit the DX25 cut-out with a little tweaking. But their FR and impedance curves are quite different: I don't have the expertise to comment on your crossover, but PETT members will give you some advice, I'm sure.

    I use the Morel CAT-378, it's similar to the 308 but has a mild horn/wave guide and is more efficient; I really like the sound, too. The 308 is used in Jeff Bagby's "Solstice", so it must also be good!

    And from PE's Project Gallery, here's some inspiration: http://techtalk.parts-express.com/fo...-walnut-veneer

    Good luck

    Geoff
    Last edited by Geoff Millar; 11-19-2019, 02:26 AM.

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    • #3
      It doesn't SEEM like you modeled any baffle step loss?
      If that's true, then try dropping the 8n(ohm) series resistance on the tweeter down to about 5n, and add 3n in parallel w/it (across).
      Your 2 notches don't look bad (target freqs.), but they don't seem to compliment each other.
      Did you just try 3rd order on the woofer?

      Comment


      • #4
        Geoff - thanks for your response. The 308 looks to be physically an exact drop in if the diagram measurements are correct.

        Chris - I didn't model any baffle step loss. I'll look into it. Also I think what you are describing is adding an L-Pad to the tweeter which I think I tried to add to TOID/Wolf's crossover and didn't make things better but I will try your suggestions. Paul had a 3rd order on the Amiga woofer RS180S but TOID (Nick) used a 2nd order which is what I went with. I'm in no rush so I will see what works.

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        • #5
          The hole in the middle will likely leave you a little unimpressed. I will also state- all I did before on that tower was to suggest a notch filter. That is all I did, and it was an off the cuff set of number values.
          Later,
          Wolf
          "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
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          Comment


          • #6
            Here's what I would suggest. Make a sim of the amiga x-over, and use it as a target. If you use PCD, you can select 3-way, and load the rs180s into both the woofer, and mid portions. Then you can compare the driver responses with different x-overs. See if you can push the breakup down some more. The Morel will cross lower than 2k with no problem, so I'd target 1.5k if necessary.

            Comment


            • #7
              rpb - Thanks for the advice. Good timing too. I was revisiting WinPCD earlier tonight! But didn't think of doing multiple sims with the same woofer. I noticed the hole in the middle too but based on what I have seen in other SPL curves that wasn't uncommon in a 2 way.

              Comment


              • #8
                Originally posted by rpb View Post
                Here's what I would suggest. Make a sim of the amiga x-over, and use it as a target. If you use PCD, you can select 3-way, and load the rs180s into both the woofer, and mid portions. Then you can compare the driver responses with different x-overs. See if you can push the breakup down some more. The Morel will cross lower than 2k with no problem, so I'd target 1.5k if necessary.
                That's pretty much my suggestion also - you've got to figure that the Amiga crossover is pretty optimized, and crosses about 2K, which is about what the Cat308 can do also. Start with the Amiga RS180 crossover, and just work on the Cat308 crossover. Lots simpler.

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