Stopped off at a few places, on the way home, to see what was available. After checking various reviews, and various other decision-making inputs, I ended up heading back out to pick up a set of Creative T60 units.

These are way smaller and lower-power than my malfunctioning Logitech Z-5500, but they work just fine in the smaller space. Plus, part of why I was using the Z-5500 was because I could run digital audio over fibre but I haven't had a system with an optical audio output in ~7 years so I was just using analog 3.5 mm. The extra speakers and sub were mostly just being used to reinforce tone and increase frequency range since I hadn't bothered orienting them correctly since moving here, had little content which would play through as native 5.1, and that didn't really matter once I lost the digital audio.

Interestingly, these work fine for analog but they also do digital audio over USB, which works fine out of my Linux box. I didn't even realize that was a thing. Sure, it is just 2.0 audio so it isn't as useful, but still a nice touch. Something which may also be useful is that they can cut-over to BlueTooth audio, which might be handy if someone drops by and wants to play something from their phone. Works like a charm from my very old phone, so that should be fine.

They definitely don't sound quite as good, but not bad, by any means. I am pleased with the purchase, so far.

Now, to figure out what to do with the old speakers,
...Nights