Reworking songs into acoustic form isn’t a new approach for Justin Bieber.

As manager Scooter Braun reminds us in the new issue of Billboard (in an interview conducted before last week’s Philips Arena concert), even “Baby,” Bieber’s mega-hit with Ludacris, was released online as an acoustic track before making its way to radio as a glossy pop bauble.So now, following the pattern of 2010’s “My World 2.0” album that was then trailed by “My Worlds Acoustic,” comes “Believe Acoustic,” the stripped version of his “Believe” album released last summer.

What is best about these acoustic offerings is that in undressed form, you get a true sense of a song. Can it sustain itself without stacks of keyboards to distractingly bleep and bloop over imperfections?  

The verdict: “Boyfriend,” no. “As Long As You Love Me” and “Be Alright,” yes. (The latter actually soars as a tender piano-based prayer – sort of a “You’ve Got a Friend” for the 12-year-old set.)

And even though there are spots with some mild echo effects and double-tracked vocals, most of “Believe Acoustic” showcases what we rarely see of Bieber in concert – his sweet voice.

On “As Long As You Love Me,” a racing acoustic guitar infuses the song with urgency, a smart balance to the “la la la”’s Bieber sings in his upper register (though he’s not quite 19, his voice continues to mature), while “All Around the World” is a faithful recreation of its electronic counterpart.

But aside from the usual devotion to all things Bieber, what will have fans salivating the most with this release is the inclusion of three new songs, all of which supposedly have some connection to his on-off-maybe-nope-off-again relationship with Selena Gomez.

“I Would,” stacked with strings and a shuffle drumbeat isn’t exactly acoustic, but it’s the most fully realized of the trio so we’ll let it slide.

On “Yellow Raincoat,” Bieber sings in a voice low and melancholy, “All the fame and the money and the girl will drive you crazy,” a purported reference to Gomez, who apparently once wore a yellow raincoat – a la Curious George? – on a theme park outing.

“Nothing Like Us” is a more obvious cry-me-a-river-over-a-broken-heart ballad, with its tinkling piano and lyrics such as “nothing can make me feel like you do…you know there is no one I can relate to.”

While it’s easy to cynically dismiss Bieber’s diary entries as a ploy to elicit sympathy from his millions of female devotees, the kid sounds genuinely sad when singing about his puppy love gone wrong.

Maybe “Believe Acoustic” doesn’t break any new ground musically, but at least it allowed Bieber a platform to share his wobbly – and quite relatable – emotions.