I have been reading this thread, checking out all the suggestions. I was just doing it silently.
yes, the Z625 is rated at 200rms/400max. But if i had to compare it to subs from the trunk of my car in my early years (90's), Id have to say it sounds as impressive as an average 10" sub with 50 watts or so (rms)
Nothing to really shake a stick at. Barely enough rattle to make the rear view mirror dance at all. Apples to oranges yes, but thats all I know in the audio field. I have much more experience with car audio than I do with home audio. I am looking for the punch that a decent 200 watt car audio provides (from the 90's, i dont know the quality of todays stuff), but in my office. and the Z625 is not up to task.
It might say 200 RMS /400 peak but both of specs are pretty much lies. Its not a Logitech specific problem, pretty rampant in low-end audio gear.
I've done the car audio thing in the mid 00's right before that started to die out. Built up a friends car with all Polk Audio and Phoenix Gold; when it was configured for SPL (1200 watts or something absurd like that) I think it hit like 136dBA, and when it was setup normal it won best of show (best overall combination of sound quality, install, and SPL), fun stuff.
For your office though your best bet if you have $700 and want to get something absolutely next level is to piece something together with separate speakers, amp, and sub. For speakers you want to make sure you get something thats going to work well nearfiled (where you sitting close to speakers) so that means either pro monitors, or compact bookshelf speakers (like the Mica I listed), or the rare coaxial driver like the KEF. To power them a small class D desktop amp with 20+ watts (real wats not BS marketing watts) will be plenty for nearfield, Topping and SMSL make really nice units, there might be others. What you don't want is a huge AV receiver or some other vintage amp with a ton of inputs and channels you don't need and that probably has less power in two channel mode than a modern compact class D amp. For the sub 8" will with 150-300 watts is plenty (again these are real watts), I think I picked a Polk but there should be other good options, JBL, Yamaha, ect. I would recommend a sealed design vs ported since that is more compact and you can be more flexible with room placement as thats a pretty big deal with subs. You don't have to go with all the stuff I laid out in my first post but that would be a good place to start.