The band has produced songs for various anime and video games, such as Kashimashi: Girl Meets Girl, Himawari!, Noein, True Tears, Yosuga no Sora, Kokoro Connect, Shinkyoku Sōkai Polyphonica and visual novels like Key's Clannad and Favorite's Irotoridori no Sekai.
The band is composed of two primary members, Riya—who provided vocals and the majority of the lyrics—and Hajime Kikuchi—who plays the keyboard and handles composition, arrangement, and sometimes the lyrics.
On September 8, 2012, it was announced that Hajime Kikuchi would leave the band "for now", after making some degrading comments at singer Halko Momoi.
[4] Eufonius had originally planned to put out a new broadcast once a month, but due to being busy, they only release two or three a year in irregular intervals.
The show primarily consists of Eufonius' members conversing, responding to listener's messages, or giving updates or general information on releases by the band.