Orion line output converter question

I have this orion line output converter...
http://www.millionbuy.com/oriorsra.html

ok so there is 6 wires.. 2 white, 1 with black stripe and 2 gray, 1 with black stripe and 2 brown wires. now i have it hooked up now to the 2 back speakers. i dont have the brown ones hooked up at all and im not sure if they are ment to be used or not.. can some one help me out?