Conversation so far:
Where was Max Martin born?
Karl Martin Sandberg, known professionally as Max Martin, was born in Stockholm, Sweden.
Where did Max Martin grow up?
Karl Martin Sandberg, or Max Martin, was born and grew up in Stenhamra, Ekerö Municipality, Stockholm County, Sweden
When did Max Martin become a singer?
Martin was a music-education program student, and as a teenager he sang in a variety of bands before joining It's Alive in 1985 as their singer and frontman.

Question: What did he do as a child to help his singing career?
Self-contained rewrite: What did Max Martin do as a child to help with his singing career?