I've searched everywhere for the artists, but I cant find it out. There's a woman singing the lead vocals, and a man in the background (sounds like a black guy, sort of gospel-ish sounding).

The guy in the background sort of echos her, I'm sure theres a technical word for that.

For example:

Woman: Siiiiiiiiiiiilent Night

Guy: Oh silent night!

Does anyone know what version I'm talking about?