If the reviews of your concert describe your singing as orotund, you can pop open the champagne — your reviewers have noticed your full, rich sound.
On the other hand, if you've just given a speech and the TV commentators ridicule it as orotund, moralistic, and meaningless, you might want to drop out of sight for a few weeks. You've been called out for your pompous, self-important style. Orotund comes from the Latin word ore, "mouth," and rotundo, "make round." So orotund sounds are what you make with a rounded mouth, which is good if you're singing, but pretentious if you're not.