Logitech X-230

I have an old Logitech X-230 subwoofer (satellite speakers are long gone).

I still have the original DB9 cable to connect the sub to the satellites, and I am wondering how to wire it to a 3.5mm aux so that I can use the sub standalone.

I purchased a DB9 Male to Aux adapter from Amazon, but it did not work because there is no way to tell the sub that the power is on (without satellite).

https://www.amazon.com/dp/B0CL689L4K?ref=ppx_yo2ov_dt_b_product_details&th=1

If anyone could spell this out for me in the simplest terms (not a pro, but a tinkerer) I would be eternally grateful.

bought this sub back in 2005 and still one of the best sounds for the budget ever. don't want to see it sit on a shelf
 
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I replaced the subwoofer module in my Logitech X-530 system (the bigger brother to the Logitech X-230) with a subwoofer that I built myself, and I moved the electronics to a separate box that I built myself as well. The results were really good and the combined system is still in use as my main multimedia system. More here - https://www.diysubwoofers.org/projects/home/boomunit/

The X-230 is a bit different though. The subwoofer is smaller and there's some sort of "dynamic bass EQ" involved in the subwoofer's operation.