It really depends on the artist. Wala namang bawal sa music e. As you can see with that Lamb Of God Vocals, sadyang may slight distortion. May delay din. Sa SOAD naman, halos reverb lang. Pero both vocal tracks gumamit ng compression (kaya it's biting talaga).
Usually ang vocal chain sa recording is: Mic > Preamp > Compressor > DAW > EQ (Plug In) > Compressor (Plug In) > Reverb (Plug In).
Sa Metal Genre, mas compressed ang vocals so that it can cut through the mix lalo na heavy intruments ang kasabay niya.
