Iggy Pop may be the “grandfather of punk,” but he’s still an angry young man and, on Soldier, his latest opus, he sounds angrier than ever. He also sounds more idiosyncratic and less accessible than he has in several years, which means that the unconverted should think carefully before betting on this set. The humor that continues to permeate Iggy’s aggressive stance will make it palatable to some, but others will undoubtedly question whether his less-than-lilting grunts and groans even constitute music. As for the lyrics, here’s a typical verse: “My girlfriend Betsy, she’s just 14 / There’s nothing better for me to do / I’m living on dog food . . . “