I was going to buy some speaker wire (16 gauge) for my new speakers/receiver and was wondering how you would tell which side is the + and which side is the - or are they the same? Do i just have to make sure the - on the speaker is gonna go into the - on the reciever? Also new receivers support banna plugs, will i have to buy them to use it? Or can i still plug the +/- wires into them? Thx