Some .DAT format files such as the ones that come with the PlugSound libraries can be used with Mach Five. This means you can buy a PlugSound library at plugsound.com to expand your MachFive sound set. To convert .DAT files for use with Mach-Five create a folder and place the .DAT in that folder. Now give the folder the name of the .DAT file, except instead of ending it with .DAT end it with .M5b. So for example if your dat file is called keyboards.dat put it in a folder called keyboards.M5b. Now place that folder in the Mach Five Sounds folder and "rescan Mach-Five sounds folder" from within MachFive, under the soundbanks>more menu.