You need a program which will import a wave file and send it via SMDI (SCSI sample transfer) to your ESI. SoundForge will do this. I believe WaveSurgeon will as well, and is cheaper, but doesn't have the features of SoundForge, though it has specific functionality to the ESI4000 sampler (which I have as well). Links to both on my site at http://www.stucki.com/krhen/music.htm