At how the wires are hooked up.
If I were in your shoes that's what I would do. John
I just bought a house with speakers installed in the ceiling of the living room, master bedroom, kitchen and patio. All of them have cables through the walls that come out at the built-in shelving. However when I went to hook the cables up to my 5.1 receiver, I noticed there were 4 cables for each speaker!!! I'm accustomed to two - a positive and negative. But these had a black, white, red and green. Any idea why there would be 4? And which two should I hook into my receiver speaker inputs?