I'm making a wall unit for my Mits 65" and equipment. The speakers will be built into the cabinet but the Sub will not. It's a small Energy ES-8. I'm going to need probably at least 25 feet to run the cable to where I'd like to place the sub. First off what's the maximum length that you can run sub cabling. Second I don't want to mortgage my house to buy one of these. How easy is it to make a cable for a sub?