Seiichi Hamada is a composer and sound designer currently employed by SEGA. He plays the bass guitar.

He began his career with Data East in September 1988. He was part of their sound team/band Gamadelic, where he was usually known as "Atomic Hanada," or often just "ATOMIC." With Data East, he worked on games like Windjammers and Karnov's Revenge, arranged music for soundtrack releases, and performed with the band for those arrangements and live in concert. He left in January 1999.

Hamada joined SEGA in February 1999. His first project was Shenmue, for which he supervised sound effects. He's recently begun composing for SEGA, working on the soundtracks for the Border Break games and Shining Force Feather.

He has a side project called PaPa's Pleasure, a band with vocalist Kiya. He writes music and performs for it under the name "Ato Titiyama." PaPa's Pleasure has written original music and vocal theme songs for several games.