Sometimes we look back at our favorite singers and realize how far they’ve come since their early years. An incredible voice isn’t always necessary when a band writes great songs, but when a vocalist goes from unpolished and off-pitch to being a skilled powerhouse, the band always hits a new level of success.

M. Shadows wasn’t always one of his generation’s top singers. When Avenged Sevenfold released Sounding of the Seventh Trumpet in 2001, they didn’t stand out much amongst their metalcore/post-hardcore contemporaries. After experiencing vocal issues so severe he needed surgery, Shadows had to reinvent his style and technique, leading to his arena-filling performances we all know today.

Early fans of Peter Steele’s thrash band Carnivore had absolutely no idea what the man was capable of vocally. Steele utilized a gritty bark on his ‘80s material, fitting Carnivore’s New York sound, but offering no melody or harmony. Steele became a master of both dynamics in the ‘90s with Type O Negative, elevating the singer to iconic status thanks to his deep bass-baritone and heart-wrenching delivery.

Mastodon’s Troy Sanders deserves a lot of respect for his growth as a singer. Starting with brutal caveman grunts on Remission, Sanders’ style was already captivating, but when he switched largely to clean singing, Troy didn’t immediately nail the technique. Live footage from the late 2000s shows how off Sanders could be on a bad night, but throughout the following decade, he became a fantastic vocal frontman for not only Mastodon, but Gone is Gone also.

Check out the 10 Most Improved Vocalists in Rock + Metal in the Loud List above.