The postmortem album can be a crass affair, but Duets: The Final Chapter manages to redeem the ghoulish conceit. The 73-minute disc features excavated Notorious B.I.B. rhymes digitally inserted into new songs by a who’s who of current hip-hop, including Eminem, Jay-Z, Missy Elliott, and Nas. When the Biggie snippets are strong and focused, the tunes are worthy additions to his too-brief canon?the fiery, prophetic ”Beef” (with Mobb Deep) and the grim, suicidal ”Hold Ya Head” (featuring a Bob Marley sample) are gripping examples of Big Poppa’s nihilistic streak. In the end, Duets works on two fronts: as a brisk-moving all-star mixtape and sad reminder of a towering talent.