Subwoofer low-pass crossover (4ohm 80hz) inductor core & bobbin

Need help finding a core & bobbin that would work for a custom inductor that im building for a 4 ohm passive subwoofer crossover that will be crossed over at 80hz. I am using 16 AWG enameled copper wire. I’m getting a little lost with all the options. This is a pilot test and will be making these in bulk if the results are what I expect.

I’ve seen a number of high end manufacturers use toroidal cores so if that is feasible or better given my requirements I’m all ears. Im new(ish) to this so any and all suggestions / improvements are welcome!


About the best I can do is give you links to our bobbins and cores.

As a starting point, understand that the inductance factor AL given for a core typically has units of nanohenries per turn squared. A core with a listed AL of 1 will offer roughly 1nH of inductance with 1 turn, 4nH with 2 turns, 9nH with 3 turns, etc.

After this, there is some product N*i (N=# of turns, i = current through winding) that will cause a given core to reach saturation and lose its ability to behave as a proper inductor, the upshot of which is that larger inductances and higher peak current values result in a need for a physically larger core.

Core materials can introduce non-linearities and sensitivities to factors such as temperature however, so it is not uncommon for applications desiring stability to use a non-magnetic core (air core) to avoid these.

There’s a brief article here that might be useful, and I’d recommend Wurth’s Trilogy of Magnetics available here and elsewhere as a thorough resource for study on topics relating to magnetic components.

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