I normally work on a PC connected to a Profire 2626 and a Macbook Pro connected to a Profire 610. When I opened my BX8 D2 box yesterday, I found out that the inputs for these monitors were either XLR or TRS inputs. Until now, to connect my Profires to my soundsystem (I was using a Mixer connected to a Yamaha PA system) I was using only TS cables, one from output 1 and another from output 2. Can the Profires outputs use TRS cables too...? I always thought these outputs were all mono ones? Any suggestion as to how I can connect two profires output to the same set of monitors without adding any noise to my sound?

TRS cables are still mono. The difference is they're balanced, as opposed to standard TS cables which are unbalanced. Balanced is better, but if your cable runs are short, it's not a big deal. Still, use them where you can. I would assume your Profire has balanced I/O's, so use balanced cables to feed your monitors. 

Thanks a lot! I've been doing it wrongly for so many years then!!!