I have some speakers. Quite old and havnt been used in years I suspect they came with an old mini system so nothing special. I was going to buy an a cheap CD and amp separate to get me started and plug them in. NOw looking at them they not only have the usual 2 cables coming out the back they have 1 big blue one with a phono plug on the end.. Whats this for? Is one for the sub as they seem to have 3 cones..

Mail me some pics