usb headphone speaker has 4 pads and ? 3 wires ?

Started by robb November 14, 2014
trying to replace left headphone speaker in a set of USB headphones with mic

Headphone very like this

Speaker like this

The circuit board part with solder pads separated from the speaker from a 
fall to floor and the wires are so fine from speaker part i can not tell 
where they are connected.

The left speaker has 4 solder pads and 3 wires (Green, Blue, Copper) are 
connected to 3 of the 4 pads

Pad [1,2,3,4] : [Blue, -- , Green, Copper]         Pad 1-2 has a red ink on 

The right speaker just has 2 wires (Red, Copper) going to it

The mic has Black and Copper going to it.

So why the 3 wires and not just 2 to left speaker ? how to choose 
replacement speaker ?

