I've read that using a better cable than the one provided by Sennheiser makes a world of difference.
I'm a musician and have got 3-4 Monster Cables from Guitar Center.
Would one of these suffice, or would you guys recommend something else?
nvm, the 2 ends of the cable are different sizes.
I haven't personally checked out the conductors of the "5" and "6" series of Sennheiser headphones, but I have with their "4" series. Once you get through the rubber insulation, their gauge of wire used is about as thick as a piece of thread. They then coat the strands in some sort of colored resin to provide some thin insulation over the conductors, and for the assembly process to move along quicker so that the correct polarity (as indicated by color of coated strand) can be soldered to the right connection within the cup. I can't imagine the "5" and "6" series being too much greater. In going from the standard cable to a custom or semi-custom one, you can have some more flexibility on length as opposed to just accepting the standard length. But, when going with a different cable, it also might be wise to re-wire the internals of the headphones all the way to the drivers. If you are moving to a better cable, it's better to resolve any choke points inside the cups, too.