Of all the concept albums done by The Who, The Who Sell Out is far and away the best. This is for two reasons: 1) the concept is razor-thin, elucidated only by a handful of bizarro segues, and 2) the music is anything but "sell-out" material, as it combines strong-boned rock and glistening mod-pop sensibilities with a healthy dose of offbeat humor. It's a weirdly perfect album that completely defied all expectations about the band. Thus, any note-for-note replication of the album had better be equally expectation-defying. Needless to say, this a cappella rendition by ex-That Dog member Petra Haden does just that, as the only instrument here is Haden's multi-tracked voice. Conceptually, it's a fresh idea, but in execution, it ultimately turns into a novelty that wears off quickly. Although Haden's voice is truly an amazing force and her incredible work in rearranging the parts is apparent, in the end the strength of the original pieces is too much for the album. If this were another album of originals and relatively unknown covers like her 1996 disc Imaginaryland, it would be a totally different story, but an album as timeless and unique as The Who Sell Out resists her efforts.