The opposite of "rose to crescendo" can encompass a wide range of possibilities depending on the context. Some potential antonyms might include: "diminished to a whisper," "faded into silence," "descended into a lull," or "dwindled to insignificance." These reversals of musical momentum could occur for a variety of reasons- perhaps the musicians intentionally decreased their volume, the audience grew disinterested, or technical difficulties interrupted the performance. Regardless of the cause, the effect is one of subversion, deviation, or dissolution, substituting a bright and thrilling climax for a more subdued, ambiguous conclusion.