Trip-hop flop?

Eleven years in the making, “Third” is a gloomy departure.

In the strip clubs of your mind, what does the soundtrack sound like? If said club is chic and downtown, its patrons and dancers bathed in a ruby-red syrupy light, wouldn’t Portishead be an ideal backdrop? Whereas the group’s previous albums “Dummy” and “Portishead” were so perfect for pole-dancing that they were probably recorded with some ultra-cool glamazon strippers in mind, their newest record, “Third,” is their attempt to clear out the clientele and shut that party down.

The British trio of trip-hoppers change pace from the sweet, airy atmospheric beats of their past and instead focus on the shades of gray. “Third” sounds like a big, heavy cloud of toxic waste determined to stomp out all the pretty yellow flowers in a garden.

If you absolutely loved “Dummy,” with its sexy slinkiness that perfectly complemented singer Beth Gibbon’s candy-coated chameleon vocals, “Third” will be a shock. It drips with a heaviness Portishead has always flirted with in their work but never fully developed.

The songs, minus “Deep Water” which could be a Paul McCartney ukulele ditty, possess a blackness that can be unsettling. It’s not quite the jazz-tinged trip-hop of “Dummy” or “Portishead,” and it doesn’t create as pleasing a backdrop as those older siblings, especially if you’re considering using “Third” as background music at your dinner party or contemplating its merits as striptease material. It sounds like the Velvet Underground at their most avant-garde (think “All Tomorrow’s Parties” and “The Black Angel’s Death Song”), with Gibbons the Nico to her bandmates’ experimental musicians.

On “Threads,” Gibbons laments, “I’m always so unsure” over a cymbal-heavy din; and “We Carry On” begins with a 30-second tornado drill drone before dissolving into a swirling storm of accompaniment. Though Portishead has never been a shiny happy band singing about trees and sunshine, the material of “Third” warrants a Prozac or two to combat its murky blues.

The members of Portishead have taken their sweet time (11 years) to craft “Third,” and even if the album doesn’t appeal to you it’s obvious that it is something its creators feel passionately about. Each and every song is as intricate as its predecessors, with exceptional care given to the quirky instrumentation that supports the ethereal Gibbons from underneath her light-as-air vocals.

“Third” is the most logical next-step in the Portishead album equation. It picks up where “Portishead” left off in 1997.

Although “Third” isn’t going to be very popular with the ladies of Déjà Vu or DreamGirls (because nobody likes a glum stripper), it is, if nothing else, perfectly suited to the band’s aesthetic. Was it worth the wait? Perhaps not the 11 years, but the time in creation was certainly well-spent.