I have a pair of these (or something very similar) :
The plug failed so I chopped it off and was hoping to wire it to a plug on a spare pair of iPhone headphones I had kicking around. Both sets of headphones have a button and microphone so I figured it wouldn't be too hard.
I was wrong. The iPhone cable has 6 wires (one white one hiding inside the red/green combo) and the sennheiser only has 4 - white, red and two coppers. I did a very quick test to see if just holding some of the wires together would give me sound in one of the ear-pieces - nothing, though I'm confident both cables are fine.
Is this maybe to do with laminate on the wires themselves? Do I need to connect red to red and a ground? I'm a noob so don't know what a ground does in audio cabling.
I would appreciate any pointers. My plan is to twist the wires together (like this - youtube) rather than solder. I also have some heat-shrink tubing.
There is a diagram of iphone pinouts here -
here are my cables: