i had the 2.1 w/ a subwoofer.the ones i got now i like a lot more, i have two speakers in rear so yeah the sound quality is a lot better and i can notice its cleaner and i can get it loud and everything.
as far as tech specs. i just looked at the wattage and thought 70 was good. after that i knew logitech would be good for speakers then saw the outstanding ratings, so thats when i decided to get it.
i know ur supposed to look at the different frequency reponses for the different speakers, like 40-20KHz for a couple, and the subwoofer has different numbers, lower, idk.
i didnt really bother with that, just saw the ratings.