Hear that? That’s the sound of Christina Aguilera trying to resurrect a career that we weren't even aware was broken.

In the four years since her last studio album,  “Back to Basic,” it’s clear that Aguilera has listened to every bottled blonde that’s hit the charts lately, plus carefully watched what gals like M.I.A., Ke$ha and Britney are doing and tried to figure out where she fits in.Almost every move on “Bionic” feels calculated and the result is an album that’s often as exhausting to listen to as it must have been to make.

Aguilera is trying to reinvent herself as a hip, of-the-moment artist when, quite frankly, no reinvention was necessary and, furthermore, she’s stripped away so much of what made her special to begin with. There are dozens of artists who can enlist top producers like Tricky Stewart, Claude Kelly and Polow da Don, and plenty who can work with the likes of M.I.A., Santigold, Le Tigre and Peaches; but there aren’t many who have the pipe prowess of Aguilera. Listening to her unleash her powerful instrument on parts of  the fierce “Prima Donna” makes you long for the days when she just sang and showed the world her vocal strength instead of worrying about copycatting other artists.  Luckily, that Aguilera returns on several cuts.

Opening track “Bionic” is a futuristic, electronic, echo-laden invitation to jet off to the new millennium with interesting beats.  Think Janet Jackson’s “Rhythm Nation,” but not nearly as captivating.  Same goes for first single, “Not Myself Tonight,” which died a pretty fast death after the initial curiosity subsided. Like much of the album, “Not Myself” seems like a tired come on with her “give it to me/don’t stop” moans and sighs.  Catchy beats save “Woohoo” featuring Nicki Minaj, which is seemingly an ode to receiving oral sex, but then Minaj drops in Interscope label head Jimmy Iovine and Warner Bros. chairman Tom Whalley’s names to snap you back to reality. Huh? On so many of these songs, Aguilera is so relentlessly desperate for us to see her as something other than a new mommy (or at least the hottest MILF to ever commit to vinyl) that instead of turning us on, it’s a tedious turn off. “Desnudate” is a fun dance track with its cries to “Get naked for me” that sounds a little like something her fellow, former Mousketeer Justin Timberlake would have recorded, complete with Donna Summer-like “Love to Love You/Bad Girls” whistles and sighs. She keeps the explicit sex theme going strong on the Barry White/Robin Thicke love jam “Sex For Breakfast,” but I don’t know if we need to hear anyone sing: “Stay inside me baby…” no matter how luxurious the groove. Halfway in, you just want her to finish already.  If she needs to wrestle up a little extra money, she could license most of the tracks for porn films.

The cuts that work best are the wildly fun, bouncy “Elastic Love” and the clap-along, schoolyard chant of “I Hate Boys.” The M.I.A.-written “Elastic Love” is an electro-synth, peppy track that compares her love to a rubber ball even though “with paper clips, they couldn’t even hold us together,” while “I Hate Boys” is pure pop infectious silliness. Same with the Le Tigre-produced “My Girls” featuring Peaches. Here, Aguilera veers into Pink territory:  they may be headed to where the boys are, but boys are definitely secondary to hanging with your buddies.

There are 18 tracks to choose from and if the electronic tracks don’t work for you much of the second half is filled with beautiful ballads that showcase the Aguilera that most of us have come to know and, if not love, respect for her awesome talent.

Aguilera has found a true collaborator in Australian artist Sia, who has five songs on “Bionic.” Most of them are gorgeous ballads, such as the beautiful, piano-driven sweeping ballad “I Am,” about Aguilera’s son, or the angelic-sounding “You Lost Me,” about a love that can never be recaptured. Former collaborator Linda Perry, the producer/songwriter behind such hits as Aguilera’s “Beautiful,” contributes the inspirational “Lift Me Up.”

There’s something here for everyone. Aguilera is certainly giving her fans quantity here, but she may have been better served by paring down to the top 10 tracks here.  And Christina: your voice is better than anyone who’s nipping at your heels.  Next time, remember that when you head into the studio.

Your thoughts?