I'm attempting to replace a broken jack plug on my Sennheiser CX400 in-ear headphones. But I'm not quite sure about the wiring. The channels aren't separated because I hear sound in the opposite channel when I adjust the balance to left or right.
There are 4 wires. Red, green, copper (ground?) and the last one is red and green.
Here's a picture of how it looks at the moment: