Breakups and Breakdowns: Rihanna's new album sputters out of control at several turns, while Christina Aguilera is moving on

There are several moments on Rihanna's new album Unapologetic in which the synthesizers sound as if they simply couldn't handle all the pressure and sputter out of control. And just as importantly, it would seem there were no sober minds around to fix them.

The song ''Jump,'' for example, starts low and sweet, then builds gracefully to an enticing synth peak at the chorus. But then it jumps to a point seemingly beyond the abilities of her poor machines. The track then bounces – no, flounces – around on fuses about to blow in extended bridges that mostly recall the sounds of an old Atari game, along with a few muffled shouts. Are those the cries of her engineers, trying mightily to steer things back to music-land?

Rihanna

(Photo by Island Def Jam)

Anyone familiar with what is now popularly called EDM – electronic dance music – knows what I'm talking about. Because this particular strain of mid-tempo sound – screechy, wobbly, hostile and totally synth-derived – has been spreading like a computer virus, infecting EDM-producing synths the world over. Some call it dubstep – or more precisely, the Skrillex-popularized, hyper-masculine offshoot known as brostep, merging the sounds of house with heavy metal, of all things.

But a better name for it would be misstep: a noisy fad that I suspect people will look back on with disdain. How could something so non-musical become so popular that it even wins multiple Grammy Awards? And so popular, even the man who is probably EDM's biggest star has now fallen sway. Rihanna follows ''Jump'' with ''Right Now,'' featuring David Guetta.

But it's not just Rihanna's misstep missteps that make Unapologetic – the prolific pop princess's seventh set in as many years – a hard slog. There's even another regrettable production from Guetta. ''Phresh Out The Runway'' is as shrill and tuneless as it is stupidly titled, and the least inviting opening track to a pop album I can remember. There's also the drugged-out dirge ''Pour It Up,'' which channels Ke$ha – and no one should ever channel Ke$ha, least of all Rihanna – in its talk of seeing ''dollar signs'' and hating haters.

It should be said that Unapologetic is one of Rihanna's more consistent albums. The sound and style is slower and more bitter than anything since Rated R, though the bittersweet end flavor is easier to take than that 2009 release. The new set even ends with another dash of mid-tempo misstep. Actually, that's not quite right: ''Lost In Paradise'' isn't offensive at all, with its light dubstep seasoning, no jarring breakdown sounds or screeches – just a robot amusingly chirping ''bass snap.'' If this were how more of today's popular dubstep sounded, I could actually sing its praises. There are other songs worth praising on Unapologetic, from the flat-out beautiful ballad ''Stay,'' a touching duet with Mikky Ekko, to the tart dancehall reggae tune ''No Love Allowed'' and the pleading two-part jam ''Love Without Tragedy/Mother Mary,'' both of which, taken together, suggest she's mostly moved on from Chris Brown. Then again, Brown joins Rihanna to coo in a Michael Jackson-channeling duet here that the duo's publicly undefined relationship, which has them calling each other baby on record, is ''Nobody's Business.''

Ho-hum.

DOWNLOAD THESE: ''Stay,'' ''No Love Allowed,'' ''Lost In Paradise''

Christina Aguilera

(Photo by Cobrasnake)

IN CONTRAST TO RIHANNA, Christina Aguilera opens her seventh album as enticingly as imaginable. The quiet, building ''Lotus Intro'' conjures the eccentric electronica of Goldfrapp, and suggests Aguilera learned from her sloppy, jarring 2010 set Bionic.

To a certain extent, she has. Aguilera sounds a lot happier on Lotus, and she mostly sings about making love, not war. Lotus is loosely a breakup album, charting a path from a seemingly bitter divorce in 2011 to a time when she mostly just wants to break loose and dance.

Of course, here, as ever, Aguilera can be a lot to take – subtlety and modesty have never been her strong suits. She generally sings – and acts – as if her life depended on it. Only the shouters – and strong-willed – survive. First single ''Your Body,'' even apart from its awful love-em-and-kill-em video, is Aguilera in total overdrive. She sees to it that her voice always overpowers the sauntering, staccato beats – a mean feat. It goes far beyond her fantastically sassy 10-year-old hit ''Dirrty'' to become unattractively filthy. Even worse is ''Circles,'' on which she childishly taunts haters – and her ex – to ''spin around in circles on my middle, middle finger.'' It makes you want to ask her point blank: How's your baby boy doing, Ms. Aguilera?

Yet when she's feeling footloose and carefree, she shines. The playful dance jams ''Red Hot Kinda Love'' and ''Around The World'' may put you in mind of Back to Basics, Aguilera's bold and fun underrated gem of an album. She even bests Madonna with ''Let There Be Love,'' which sounds like a dead-ringer for ''Girl Gone Wild,'' but without any embarrassing lyrics.

Meanwhile, the marching, mid-tempo ''Cease Fire'' is demanding and forbidding, and may take you a couple listens to warm up to. But in the end, this stirring and mature track is what makes Lotus gel as a package. Aguilera chants as much as she sings on ''Cease Fire,'' and the music gives way to an angelic chorus as she calls for peace and harmony and individual resolve to end hopeless fighting and casualty. ''Calling out, white flag, I surrender,'' she chants. ''Hear me now, make it stop, we can do better…In the end, what is it worth, what is our legacy?''

Breakups don't have to be totally bitter, she's saying – or involving spins on middle fingers.

DOWNLOAD THESE: ''Red Hot Kinda Love,'' ''Cease Fire,'' ''Best of Me.''