The System's sophomore album set the Big Apple duo well apart from the growing pack of electro-dance duos that proliferated in the mid-'80s. While Mic Murphy made a distinctive and soulful frontman, it was keyboardist David Frank's mastery of studio technology that gave the System its edge; X-Periment showed that his only rivals in creating the hip-hop-flavored dance music of the day were producers Arthur Baker and John Robie. The supple grooves here wiggle well beyond the disco lockstep of the band's debut, and the incredibly busy mixes make for consistently entertaining listening. If there's a weakness, it's that, as on the first album, the melodies are often sketchy, and songs like "Dangerous" lean too heavily on Frank's studio wizardry. However, X-Periment also contains two of the System's best-ever tunes, both written with guest guitarist (and Madonna sideman) Paul Pesco. "Promises Can Break" is a sweet showcase for Murphy, tipping the group's trademark balance between hi-tech and humanity firmly in favor of the latter, and "I Wanna Make You Feel Good" is even better, a far superior rethink of "You Are in My System," the band's big hit from its debut. Beneath the layers of squiggly synths and cracking electronic percussion is a Prince-ly pop song that deserved to be a breakout hit -- something that eluded the System until 1987's more restrained "Don't Disturb This Groove."