Thresholds is the second full-length studio album from Florida death metal band Nocturnus. It was released in 1992 by Earache Records and follows the band's debut album The Key.Thresholds continued the experimental sound created on the first album and the line-up was expanded to a six-piece with the addition of a vocalist – allowing Mike Browning to concentrate solely on drums. Lyrical topics range from opener "Climate Controller" (possibly a device that must control the earth's climate after global warming), "Aquatica" (about a race that has evolved in the ocean to overtake humans) and "Gridzone" (about an alternate planet capable of life).. "Tribal Vodoun" is about primitive religions and voodoo, while "Subterranean Infiltrator" is inspired by the Metal Gear video game series.The production of Thresholds is considerably more polished than that of The Key. The music is also more complex and mature. The time signature changes at least once in every song and there are numerous breakdowns and tempo changes in every song. The band's musicianship has also advanced. Guitarists Mike Davis and Sean McNenney play longer, more melodic but even more technical solos (now often with a Jason Becker-esque neo-classical flair). Mike Browning's drumming has become more technical and precise than it was on The Key, not to mention his drum tone has improved. Louis Panzer's keyboard lines are more complex and he even takes solos on a few songs. The bass (now played by Chris Anderson) is much more audible than on The Key and is also highly technical. Dan Izzo's vocals are much deeper and clearer than Mike Browning's, often compared to the vocals of Max Cavalera of Sepultura."Alter Reality" was released as a single and featured a music video that received substantial airplay on MTV's Headbangers Ball. "Arctic Crypt" and "Climate Controller" also became notable fan favorites.