Originally Posted by Tjj226 Angel
Cheapest thing to do would be to go to a hardware store and get some plastic dip. Simply dip your wire in there, pull it out and let it dry. Repeat for thicker insulation.
Plastic is not going to do anything to prevent EMI. You would need metal (say foil) and it would need to be grounded at both ends so as not to act like a giant antenna (as in the case of shielded Ethernet cables). I'm not familiar with that mic, but usually a decent XLR cable will do a pretty good job of dealing with interference on it's own. If your mic uses a 1/4in jack only then you really don't need to worry about EMI as that mic is probably the problem. You might want to check if your phantom power box (tell me you're not running with phantom power from your mixer!) unit is getting clean power.
Other than that, the only way to avoid EMI on signal cables is to route them away (say at least 3 or 4 feet) from power cables. This can be a huge pain but is pretty much unavoidable. I've torn down and moved my little project studio around more times than I want to admit to combat this very issue. If you can, I would suggest hanging your XLR cable from the wall or celing if you can't find a place to lay the cable down. It will look terrible (say a hook and some string) but it works really well. That said, be sure it's the cable and not the source of your phantom power that is the problem. Keep in mind that florescent lights (even CLFs) are the devil. The only other thing I would suggest is going with 48v instead of 12v assuming your mic can do that. It always seems to help with my larger condensers.
Edit: In summation, string, thumbtacks, duct tape, maybe a picture hanging nail if the tacks don't hold. I've seen that sort of thing done in studios charging $350/hour so don't feel bad it it looks ugly. No one is gonna ask if your studio space was attractive when they listen to your recording.Edited by RandomK - 12/13/12 at 12:01am