I think conventional useage on these boards is 6.1 has front left, right, and center, left and right surround, and a rear center, while 7.1 has front left, right, and center, left and right surround, and rear left and right. Of course, since nothing (to my knowledge) is produced in discreet 7.1, the rear left and right of 7.1 use the same signal as the rear center of 6.1.

Confused yet? Somebody else hop on and give a different explanation!

I am the Doctor, and THIS... is my SPOON!