Apart from the connesion made beetween '80/'90 Goth and '90 Metal/Doom, it had to be noted that the firsts real '70 doom albums, the first Black Sabbath (expecially the title track), Death Walk Behind You by Atomic Rooster,Black Widow, Hight Tide, Quatermass and other obscure Doom/ProgRock groups where Heavily Gothic... songs and LP covers inspired by Hammer films, HP Lovercraft or Poe novels, trace of spiritism and various kinds of occultism, witchcraft...
... when did the SludgeDrone enter with so great force to erase all the gothic ovetones? Was after grunge? Was all because Earth 2? Overcoming of the drone minimalism and refuse of mysticism (which was in various grade and tones present in Death and expecially obviously in Black Metal) is all of what we now call Underground Metal?
But wait a minute, this deep darkness pit of extreme sludge, hypnotic, the black drone, this absence of everything else except murk metal trasmission, the time perception distorsion, this lightless lethargy, has spiritual dimension, right? Vibration it is. Sounds to watch the abyss by.