BTW, I know where you’re coming from, I did this myself once, too, though not as bad. I had (well, still have) an older Onkyo theater in a box (audio receiver mostly, no HDMI) which actually had some pretty nice speakers (6 or 8 ohm, not sure which), but had a passive sub, when I got a new receiver for the living room I ordered a full 7.1 surround Onkyo speaker set just to get the sub and have spare speakers in case I blow out any… but then ended up using the new surround speakers with the old Onkyo receiver and its passive sub in another room as my 3rd surround setup (simpler needs in that room). Anyway, I had less I needed to replace, but was still faced with a dilemma when I figured out I got screwed on the passive subwoofer.