felt, sounds like you need to read up on filters and what they are used for. The MFC is basically a bunch of filters in an MPC mountable rack AFAIK.
In basic terms a filter can "Filter out" frequencies of a sound, depending on what kind of filter you're using (what setting not what model of filter). You can take out hiss, enhance bass etc etc. There's a lot more to it than that but that's a start.
www.tweakheadz.com is a good place to start if you're just starting out making music. Check out "The guide".
If you are just starting out, I would advise you to learn the gear you have before buying stuff like filters etc. Too many options can be overwhelming and a waste of money if you don't need it!
Good luck
