hooking up mpc to interface and speakers

i just got some yamaha HS series monitor speakers, and i am trying to hook them up to my mpc through my m audio interface. when i try to play something, it comes out really low and there is no way to turn it up...is there a setting i need to change in the mpc? or am i doing something wronge? anyway please help

sup, im using a m audio interface and hs monitors too, catch me on aim, I'll help.