Metallica is a magnet for performers dedicated to covering the band's music in a manner 180 degrees removed from its noisy, aggressive origins. Consider Fade to Bluegrass: The Bluegrass Tribute to Metallica and Rockabye Baby!: Lullaby Renditions of Metallica, two discs so dopey and ear-wrecking that they're capable of making Metallica guitarists Kirk Hammett and James Hetfield hang up their six-strings in shame. In contrast, the axmen might actually find some appeal in Harptallica, which performs today. The central conceit harpists Ashley Toman and Patricia Kline gently caress rather than bludgeon Metallica's melodies is pure gimmickry. And yet the classically oriented arrangements applied to numbers such as "The Unforgiven" are comparatively thoughtful, allowing Toman and Kline to delve into the compositions' inherent drama. It's still a stunt, but one delivered with plenty of pluck.