MPC expansions are built to be used in MPC Beats, MPC 2.0, and standalone MPC's. 

Depending on your operating system, they will be found in the location listed below. 

Library > Application Support > Akai > MPC > Expansions 


The audio files are organized into MPC format drum and instrument programs, and the raw audio files will be found in the folder labelled "content" in the locations above.