Ottmar Liebert makes smooth music, the kind of airy fare you might hear in a dentist's office. But though his tunes border on new age, his work ethic is resolutely hardcore: The German-born guitarist has been issuing "nouveau flamenco" guitar records since 1989, cranking out 25 albums' worth of live and studio recordings at a prodigious pace. Digging farther into his catalog, however, reveals some interesting finds. In the '80s, before establishing himself as the king of mellow, Liebert played guitar in RED, a post-punk, synth-driven Boston band. According to MP3 blog A Viable Commercial (http://goutroy.blogspot.com), which specializes in forgotten post-punk and new wave, the group issued two 45s with hand-painted covers and tape-and-paper designs. The group's taut, funky leanings are a far cry from Liebert's flamenco work and collaborations with soft-poppers like Kenny Loggins, Diana Ross, Santana, and Celine Dion, but listening to the songs makes for an interesting contrast. It would be freaky to have dental work performed to a soundtrack of RED's spastic, twitching "Rooftop."