At first I was thinking - wow, despite the embarassing nature of that Doomy video, he actually has quite a decent voice. He's singing very much in tune, etc.
But on listening closer, I am pretty darned sure there is some sort of auto-tuning software that has been applied. Listen to the stepped sound on the voice during the transition between notes. If you are familiar with this type of software than that trademark artifacting should be quite audible....sometimes it's used on purpose to make an artificial effect in pop songs. In this case I think it just wasn't hidden well enough.
