4 way crossover

Hi,
i really, really need some help in designing a 4-way crossover for these drivers:
1. SPH 300TC (MONACOR: SPH-300TC)
2. Two of SP-304PA (MONACOR: SP-304PA)
3. Two of SP-165PA (MONACOR: SP-165PA)
4. Sp280DT (MONACOR: DT-280)

Attached is my crossover attempt with Xsim but I think I`m way over my head with this one. I already have the drivers (let`s call them an inheritance) and I want to make good use of them. Thanks in advance for any help in making this 4way crossover a reality and a dream come true as my daily speakers.
 

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Firstly I'd like to point out that the data doesn't appear correct when I view it. Is the impedance of the individual drivers in the 40 ohm region?

Secondly, and I realise that nothing can be done until the first point is dealt with, you have some troublesome low impedance conditions in your crossover. For example where you have 0.12mH inductors in series, then capacitors to ground. Much of the sound is being shorted straight back to the amp and this could be a problem.
 

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  • Screenshot from 2020-09-06 15-43-57.png
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putting aside the crossover (your really need to go back to basics there), the drivers don't seem be a particularly good combination because the sensitivities don't match that well, and the SP-165s don't seem to be a good midrange for hifi. If the speakers were mine, I'd sell them and make a good 3 way with better drivers, perhaps following a proven design.
 
Hi Allen,
here are the graphs 300TC s the woofer, 304PA MidW, 165PA Med, 280dt TW, thanks Alin
 

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  • 300TC.jpg
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  • 3004PA.jpg
    3004PA.jpg
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  • 280DT.jpg
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  • 165PA.jpg
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  • curves.PNG
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Last edited:
Ok, it seems this is indeed correct. What can I use as an alternative to FPtrace because it seems it doesn't work correctly.

Thanks,
Alin

I suspect that fptrace is working just fine. The correct question should be: "What am I doing wrong?" To which the answer is you probably didn't set the y-axis scales on the left side of the page correctly. Maybe the x-axis too.

A helpful tip before tracing the response is to always check that the x- and y-coordinates are correct by placing your curser at a couple of places on the graph and then verifying the values are correct down in the bottom left corner of the program.
 
Hi, thanks for the tips but i set the axes correctly. Manage to them with vituix after 2 or 3 tries. The catch is to set the y axis as close as you can like 70 or 80 db to 100 db. If you use 20 to 100 the result will be wrong every time. I will update everything tomorrow. Thanks, Alin