4 wire speaker wire is used in many applications, including home theater systems, car audio systems, and professional audio setups. The four wires are typically color-coded red, white, green, and black. The red and black wires are the positive (+) and negative (-) power leads, respectively. The green and white wires are the left (L) and right (R) audio signals. In a typical home theater setup, the front left and right speakers are connected to the receiver using the red/black wires, while the surround sound speakers use the green/white wires. If your receiver has bi-amp capability, you can use 4 wire speaker wire to connect the front left and right speakers directly to the amplifier for increased power handling.