Why do any number of Studio One v4 instruments have a perceptible and very aoying background noise floor in them?

There is an aoying "background" noise in several of the Studio One v4 instruments -- e.g., several pianos that caot be eliminated or masked. It renders the instrument useless and forces me to look for alteatives. I like the basic sound, but the quality is below par. Is this a known problem, or am I possibly doing something to cause this? I've checked the issue on multiple computers I own since I have several locations in multiple states where I do work in the studio.