Seiichi Hamada is a composer and sound designer currently employed by ACT-AGE. 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 usually used the aliases "Atomic Hanada" and "ATOMIC." With Data East, he worked on games like Windjammers and Karnov's Revenge, arranged and performed music for soundtrack releases, and performed with the band live in concert. He left Data East in January 1999.

Hamada joined SEGA in February 1999. His first project was Shenmue, for which he supervised sound effects. He later began composing for arcade games developed by SEGA's AM2 division, like the Border Break series and Virtua Fighter 5.

During his time at SEGA, Hamada also composed under two pen names: "Daichi 'Ace' Hasemi" for Tantei Jinguji Saburo games developed by WorkJam and "Ato Titiyama" while working with vocalist Kiya in the band PaPa's Pleasure. PaPa's Pleasure wrote original music and vocal theme songs for several games.

In 2015, Hamada left SEGA. In July 2015 he joined ACT-AGE, where he works as a sound designer alongside former AM2 composer and guitarist Tomoya Koga.