Though it’s been more than a decade since their last (live) album, Portishead remain as invitingly somber as ever. While the band’s third studio album doesn’t stray too far from the cloudy atmospherics that have earned this trio from Bristol a diverse and devoted following, its lack of novelty — mainly due to the fact that in 2008 Third doesn’t seem quite as surprising as their debut album, Dummy, did in 1994 — shouldn’t confound expectations either. Portishead specializes in unthreatening melancholy. (Notice how the alarms on the opening track, “Silence,” sound more festive rather than ominous.) This lends their music an insular quality that’s evocative without being dreary. Much of this can be ascribed to vocalist Beth Gibbons’s frosty delivery. Gibbons can make lines as bluntly vulnerable as those that appear on “Nylon Smile” — “Looking out I wanna know someone might care / Looking out I want a reason to be there / ’cause I don’t know what I’ve done to deserve you / I don’t know what I’ll do without you” — appear eerily serene. Of course, kudos must also be given to Geoff Barrow and Adrian Utley, who are both multi-instrumentalists and producers on the album, for their remarkable ability to create musical textures that are as delicate and substantial as a tiramisu. Note that the lead single for Third, “Machine Gun,” is one of the more disappointing tracks on this album, which deserves to be listened to in its entirety. Still, listeners on the fence would do well to check out the songs “Hunter” and “Plastic” to hear the band at its best.