In facts, Ketron say about GROOVES !!!

It's not a loop in Wav format.

Ketron sample a drumer or a loop in wav format. They cut the loop into each event of the loop (you can do it with the loop editor in SONAR) for exp each quarter note, and they are doing a kit with this notes, they call it "LIVE DRUM". After they plays it via midi . now, you can move the tempo a little, and it sounds good....

But there is another way, with wav synchro...
but I don't know very well...