Not to be confused with the international chemical company of the same name, the Germany-based duo of Cem Oral and Ingmar Koch (who go by the names Jammin' Unit and Dr. Walker, respectively) have been making hard-hitting acid and techno as Air Liquide since the early '90s. Recording first for their own Structure label group before signing with Rising High in 1993, the pair also recorded for the New York-based Sm:)e Communications (which issued 1994's double-CD The Increased Difficulty of Concentration and several 10" EPs), as well as in various side projects for labels such as...