Audeze - 3 conductors per side?

Why do Audeze headphones have 3 conductors per side? Doesn't the driver need only a positive and a negative connection? This confuses me, please help.


Yes, I understand an XLR connection at line level will be 3 conductors just like gdnrob says, but to connect to a speaker driver, wouldn't it be just 2 conductors?

OK, I got my answer on Google Images. I know, I've been living in a cave in Tibet. So it seems they join pins 1 and 3 to ground making it really only 2 conductors to the driver.

If the cable is shielded, then the shield should connect to the (-) pin only at the source end.