The Fleet of the Strongest Women "Encore" episode.
Minmay ended a war by moving the hearts of countless alien warriors with her voice. Bassara does the same, only he turns them all into squealing fangirls.
The Which one Do You Love? "Encore" episode has Miria panicking when she gets sick and thinking she's about to die, which turns into hilarity as she tries to marry off both Mylene and Gamlin (not to each other) and steals a Sound Booster to sing "one last song" for the fleet... only for the doctor to reveal that she has a cold.
When watching the Jamming Birds squadron epically fail at replicating Fire Bomber's musical awesomeness in battle, Exedol comments that he sometimes wonders why the Protodeviln haven't wiped the whole fleet out yet.
Episode 34. Gigil singing. Wow. Even the other Protodeviln he was fighting are so stunned that they just let him go.