Hows the bass on those M200s? Do they have a subwoofer out in case you'd like to upgrade?
They have pretty good bass for speakers of this size.
I did a couple test measurements with RoomEQ Wizard to check its functionality before I moved the SPL meter into my theater room to do my actual measurements.
In those preliminary tests, it was clear that my computer room has some acoustic issues, but the Swan M200s went down to the 50Hz range as advertised. I have a hump in the bass due to room characteristics above 50Hz, so it's a little hard to tell exactly what's going on, but I do not feel like I really need a subwoofer with these.
The M200s do not have a subwoofer pre-out. If I wanted to add a sub, I'd probably just run my analog audio out from my PC to a subwoofer with line level input/output and then run the output to the Swans. I'd level match them with the gain/volume control and then use Windows volume control to change volume while I left the gain/volume on the speakers and sub set as calibrated.