Can someone explain the difference? I'm setting up a percussion ensemble. I used the Percussion Ensemble in Aria, then changed around a few instruments and saved it (user ensemble). But when I left it and came back, I got different instruments. My save was lost, temporarily until I reloaded it. I saved the same combination as a Preset, and this works fine. Why would I use Ensemble? I'm thinking of treating each section of the orchestra, i.e. each string part, winds, brass, perc, etc as ensembles, but why not use Preset. I seem to be able to do the same thing.