AC/DC ROCK OR BUST

Economy counts for a lot on an AC/DC record. As meaty as they are, they sound best when they're lean -- when there's not much fat on the bone, when they choose not to indulge in a fourth chord. Rock or Bust, the group's 15th studio album, benefits from a modest sense of scale. It's just 11 songs, the fewest number of cuts since 1995's Rick Rubin-produced Ballbreaker, but a better way to view it is that it's not even 35 minutes long, making it the shortest album AC/DC have ever released. Maybe that's a reflection of the album's difficult birth. During recording, the band revealed that founding guitarist Malcolm Young was suffering from dementia, leaving his brother Angus in full charge of the band. Angus and producer Brendan O'Brien, who helmed the group's 2008 predecessor, Black Ice, enlisted the Young brothers' nephew Stevie to fill out some parts and the band whipped the record into shape in short order (admittedly with not much help from drummer Phil Rudd, who was tardy in the studi