a guy i know does those kinda voices for a big production company. from what i remember the signal chain looks something like this:
very dead room, big condenser mics like neuman tlm,u87 brauner etc -> subtractive EQ -> heavy 1176 -> C4 (bands devided at 150, 2k, 4k, top ) -> L2 until it is a block. emphasize <150hz stuff in the c4