The phrase "belted out" is often used to describe a powerful or loud singing voice. However, antonyms for this phrase could be used to describe softer or more delicate singing styles. Some suitable antonyms might include whispered, crooned, cooed, or murmured. These words suggest a gentler, more intimate approach to singing, rather than the forceful and theatrical delivery implied by "belted out." Additionally, synonyms for "belted out" might include shouted, bellowed, or roared, all of which suggest a certain degree of aggression or force. By using the appropriate antonym, writers and speakers can convey more precise nuances of tone and style.