I'm a fan of Tool and I've always been impressed by Maynard's powerful vocals, but I've noticed that his way of singing has taken its toll on him and he can't do anywhere close to what he used to.
I follow Rob Chapman on YouTube and a while ago, I saw he was taking professional vocal lessons and he learned how to do the strenuous without hurting himself. Not too long after, his band released the song "Catalyst", which showcases his vocal grit/growl and his ability to "scream".
I already know how to do that scream in the higher registers (although it sounds like if you mixed Axl Rose, Chris Cornell, and a dying cat), but what I want to do is learn how to get that rough grit in the lower registers without having to strain myself or damage my vocal cords because I can't do it natural as I can in the higher register.