One rarely hears the term "underground rock" used any more, since the breakdown of the traditional indie/major dichotomy has rendered any stylistic notions attached to the term pointless. However, the term underground hip-hop is still very much in use, probably because mainstream hip-hop is such a slave to popular formulas.

New Jersey rapper Dalek (Will Brooks) is underground in the purest sense, meaning he's cultivated a following mainly through touring. Dalek and his production partner, Oktopus (Alap Momin), met at school in the mid-'90s, dropped out and invested in a home studio where they recorded their first album. Since then, they've hired turntablist DJ Still (Hsi-Chang Linaka) and spent all their time on the road, where they've opened for acts as diverse as The Roots and The Dillinger Escape Plan, but their blend of Bomb Squad cacophony, willful dissonance and free-form electronica place them at the fringe of any genre you'd care to throw out, including hip-hop.

Oktopus's grinding grooves and Dalek's gymnastic wordplay -- a smooth conflation of rhyming and declamation -- produce the excitement we expect from rap music, but the equally requisite confrontational aspect is completely different. Though Dalek occasionally drops a political comment, his concerns have less to do with the 'hood than with the state of his soul, which is a very dark place indeed. And Oktopus rarely allows the listener a chance to relax. Last year, they even released a collaboration album with German drone legends Faust. It was a true vision of Hell, which is as underground as you can get.