When Finland’s Apocalyptica released 1996′s self-explanatory Plays Metallica by Four Cellos instrumental album, their convincing classical interpretations of those ubiquitous heavy metal anthems were widely praised for their virtuosic execution and ingenious concept, but similarly dismissed as a one-time curiosity. And cynics were almost proven right when the spread-legged and seated quartet’s sophomore outing, Inquisition Symphony (1998), proceeded to repeat the same gimmick, only adding a few instrumental originals and new bands covered (Sepultura, Faith No More, Pantera) amid the expected Metallica tunes, for a significantly less acclaimed and low-selling product. Here’s where things got interesting, because the members of Apocalyptica actually realized they were living on borrowed time, accepted the daunting challenge to evolve or perish, and went on to compose most of the material found on subsequent albums Cult (2000), Reflections (2003), and Apocalyptica (2005), while incorporating new elements like drums, bass, amplification for their cellos, and even guest vocalists. All that — plus embarking on a regular touring regimen that converted enraptured audiences worldwide — made it possible for that one-time “novelty” band to deserve a two-disc retrospective, like Amplified: A Decade of Reinventing the Cello, which traces the above-described sonic and creative evolution with an imperfect but well-balanced survey of cuts from each of those albums and phases. Looking through them: the verdict on which Metallica covers were chosen (four of them in all, including “Enter Sandman” and “Master of Puppets”) are of course quite arbitrary, depending on the listener’s personal favorites, and it’s a pity that the wrong Sepultura cover was used — that being the better known “Refuse/Resist” over the more complex “Inquisition Symphony,” which was stupendously well-suited to a classical reading. But the selection of later day, self-penned tracks fares quite well, representing a comprehensive cross-section of their dynamic, creative, and emotive range: from the metal-steeped aggression of “Harmageddon” and “Betrayal/Forgiveness,” to the rock and industrial-inspired aspects of “Somewhere Around Nothing” and “Heat” to the often balladic and controlled classical discipline of “Farewell” and “Kaamos.” And in order to enhance the retrospective’s collectability, disc one closes with a previously unreleased cover of Slayer’s “Angel of Death,” while disc two collects no less than five rare, unreleased, or alternate versions (out of a total of eight) showcasing the aforementioned guest vocalists, including Sepultura and Soulfly legend Max Cavalera and German rock icon Nina Hagen, whose schizophrenic contribution to “Seemann” (part screech, part opera) is every bit as queer as one could have hoped for. In the end, the only thing stopping Amplified from feeling like a definitive Apocalyptica anthology is the fact that the band is still actively releasing records (and evolving: diving headlong into guest vocal performances on 2007′s Worlds Collide). Certain listeners (especially straight-up classical music fans) may prefer to focus exclusively on one aspect or another of their sound, but for those seeking a broad overview by way of introduction, Amplified is about as good as it gets. – Eduardo Rivadavia