A spinoff of the game music Medley series, the Symphonic series is a specific form of videogame BGM medley; instead of simply cutting and pasting bits of music and sound effects together to make a song, Namco remixes the game music with orchestral instruments, giving them a fresh concerto-like feel. Because of the nature of orchestral music, the BPM for each of these medleys are very unstable and change very often throughout the song. The series began on Taiko 10 arcade and is still quite new.
All three songs currently in the series have 'Symphonic' as the first word of their titles, and have difficulties averaging from 6* to 7* on Oni. They are usually pretty limited to a few releases per song. Katsuo Tajima (田島勝朗) is the person who composed all three songs.