Decent speakers for a PC

[Grador]

Now I do have a couple more questions for you, to know precisely what I can do with it:
- Since these are amplified speakers, is it correct that I can connect an iPod (for example) directly to the speakers with a stereo 3.5mm to RCA adapter, should I want to do so?
- Say I want to add a subwoofer to this system later on, how can I do that in practice? Will I have to use Y-cables and filters as ImcLoud suggested?

Yes and Depends

You could plug you ipod directly in, being careful to do all plugging with the speakers OFF and the the ipod started at the minimum volume and slowly turn up from there.

For the subwoofer there are a few ways this can go. Some subwoofers will accept an RCA input and have a high pass filter on the RCA out effectively doing the job of the Y-cables and filters ImcLoud suggested. Some have the in/out RCA plugs but no crossover so you could skip the Y-cables but still need the filters. You may decide that the speakers behave just fine receiving the bass in addition to the subwoofer making the filters unnecessary [but it is likely that the filters will be a good idea].