songfest

[ sawng-fest, song- ]
/ ˈsɔŋ fɛst, ˈsɒŋ- /

noun

an informal, often spontaneous gathering at which people sing folk songs, popular ballads, etc.
an informal gathering at a studio, concert hall, or the like, in which people participate by singing along with the performers.

Origin of songfest

First recorded in 1915–20; song + fest