Sega Sound Unit [H.] was one of Sega's in-house bands, a spiritual successor to the S.S.T. Band that had two former S.S.T. Band as members, Hiroshi Kawaguchi and Takenobu Mitsuyoshi. They have arranged and performed pieces on recent releases from Sega's Wave Master publishing label and have a relationship with 5pb., contributing pieces to the Etrian Odyssey super arrange albums and performing at the Extra - Hyper Game Music Events.

The name H. is short both for Hiro and for Hitmaker, as this was the sound team to Sega's internal development studio of the same name prior to being reverted back into Sega AM3 and later dissolved into the company's other arcade divisions.