The Backstreet Boys struck a defensive stance on their 2005 comeback, titling it Never Gone as if they hadn't been dormant for about five years.

Never Gone was greeted by the requisite flurry of press and a modest amount of success, turning platinum without really generating any real hits -- enough to revive their career but falling just short of making them stars again -- so it's not entirely a surprise that in the year following its release, Kevin Richardson left the band for a solo career while Nick Carter tried his hand at reality TV, teaming up with his sibling for E!'s House of Carters, a move that gained Backstreet Boys about as much publicity as Tommy Lee Goes to College did for Mötley Crüe.

Carter wasn't about to leave BSB, though, he was just biding time until the group assembled their next album, 2007's Unbreakable.

Bearing a title equally as defiant as Never Gone, the Backstreets do sound a little bit shaken here, as they revive a modicum of their sound of 2000, all the better to balance the somewhat stodgy adult contemporary vibe of their 2005 album.

These dancier, poppier moments -- such as "Everything But Mine," which opens the album after a slight harmony intro from the boys; "One in a Million," which conjures memories of the stuttering eight-note beats of "Larger Than Life"; or "Any Other Way," which doesn't quite have the guts to go completely Futuresex in the way its thumping electro-beat suggests, so it slides into Chicago territory -- are used as window dressing for tunes that aren't as lively as "Everybody (Backstreet's Back)," but the lighter touch does help the many ballads.

Also helping Unbreakable is the focus that a handful of producers give it: most of this is produced (and often co-written) by Dan Muckala, who specializes in keeping things breezy, both on the ballads and up-tempo tunes, and the John Shanks, Emanuel Kiriakou, Billy Mann, and JC Chasez productions fit seamlessly next to each other.

So, like Never Gone, the basic sound of the album is good, but the problem is that few of the songs stick -- even less than they did last time around, which is too bad because the biggest Backstreet hits, like "I Want it That Way" and "Quit Playing Games (With My Heart)," crossed over from the teen pop genre because the songs were so strong.

Here, the Backstreet Boys don't have any songs that will lift them out of the adult contemporary world -- but the audience who has turned from teens to adults with them will likely enjoy its easy sound, as there is nothing bad here.

There's just nothing great, either.