Music based on scales different from the ones used in classical European and American music -- modal scales and scales with quarter tones -- may sound "out of tune" compared with what we expect to hear. However, I don't think this explains why Pete Cooper and Stacey Phillips sound out of tune. They're probably just out of tune.

People who play out of tune at jams really bother me. I just can't tolerate the sound. I have to move to a place where I can't hear them or leave the room.

In a similar vein, I've wondered about people who can't carry a tune but sing solo in public anyway. I wouldn't dare. One of my friends says that these people don't know that they're singing out of tune. Would you agree?