Related Clues:

• Like singing sans instruments
• Nearly all clap ape surprisingly singing like this?
• Like some college singing groups
• Like Pentatonix numbers
• How Gregorian chant is sung
• Singing without instrumental accompaniment
• Without instrumental backup
• Like singing in the rain, usually
• A better rice dish American put away, wanting accompaniment
• Unaccompanied, in a way
• Putting a lid on piano, celebrated vocalist demonstrates one way to sing