What is Fader, Center, and Matrix? (In speakers)

[gumbob3]

Just got some new speakers and on the control, you can adjust 4 things (Volume, Sub, Fader, Center), and turn Matrix on or off. I know Volume is loudness, and sub is bass, but could someone please explain the others to me? Thanks!!

 

[ssddx]

fade is generally front-back balance. center may be left-right balance. matrix may be upmixing of stereo content to all speakers instead of pushing to just the front.