If we use the ocean floor to symbolize the human psyche, then Isis are viperfish--the menacing, self-illuminating creatures who live in the deep water where the sunlight cannot reach. Isis scavenge the darkest and coldest emotions found in the abysmal waters, and send their findings up to the surface for those people with a penchant for extreme noise and bludgeoning guitar riffs.

Isis' new five-song EP, SGNL>05, documents their progress in the quest to map the murky edges of heavy music--a quest begun in 1997. A handful of serious players in the Northeast hardcore scene came together and started fleshing out what would become 1998's punishing Mosquito Control EP. A brief shake-up soon after, and Isis solidified its lineup out of the remains of such hardcore bands as Cable, Loga, Unionsuit, and Cast Iron Hike.

In 1999, Isis followed their initial offering with Red Sea, a seven-song depth charge of bleak, writhing force--one with a blast strong enough to catch the ears of tour-mates Neurosis, who were building up their autonomous new label, Neurot Recordings. Like-minded in their experimentation in the more ominous aspects of human nature, Neurot brought Isis into their fold and, in March, released SGNL>05 (which serves as a companion CD to Isis' Celestial album on Escape Artist Records). SGNL>05 is a schematic of the life cycle. It is a brooding, ambient diagram of peak, decline, and rebuild, articulated through D-tuned guitars and eviscerating studio quirks. Even singer Aaron Turner's sandpaper howls become a blunt weapon in the kicking and screaming free-fall to the bottom.

While maintaining the level of intensity in their prior releases, SGNL>05 finds Isis pulling in new sounds, employing everything from eerie sonar pings and cavernous guitar effects to haunting piano notes and blown-out vocal tracks. It all comes together, providing the listener with a topographic survey of our most foreboding depths.

Isis will be sharing the stage with Soilent Green, Witch Mountain & YOB this Tuesday. All in attendance are sure to have their perspectives altered and their guts rattled loose.