She comes up a bit light

Are we witnessing the death of a dynasty?

The way things have been going, the new album by Janet Jackson that arrives in stores today could be one of the final acts of a royal line that’s presided at the center of pop music for four decades.

Now the Jackson 5 is long gone, Michael Jackson is way gone and the legacy that produced “ABC,” “Rock With You,” “Billie Jean” and “Rhythm Nation” has dwindled to this, the suddenly sputtering career of little sister Janet.

The title of her new collection, “20 Y.O.,” alludes to the 1986 release of “Control,” her first “grown-up” album, the one that made her a legitimate successor to brother Michael as the Jackson clan’s hit-maker and media star.

In the first of the several spoken interludes that lend the album a casual, homey feel, Jackson does some summing up: “I’ve talked about racism, spousal abuse, empowering women, children.... I’ve covered a lot in my 20 years.”

Now she sets a more modest agenda. “I want to keep it light. I don’t want to be serious. I want to have fun.”

If you’re thinking “fun” means you-know-what, you’re right. “20 Y.O.” primarily has sex on its mind, in terms just slightly toned down from the heavy-breathing level of its predecessor, 2004’s “Damita Jo.”

In the opening set of songs alone, Jackson promises to do it all, says you’ll have to work for it, compliments you on a job well done, tells you how to do it and assumes the identity of a model in a men’s magazine. And she manages to do this without sounding especially raunchy.

But if she keeps it light in terms of artistic goals, especially compared with the ambition of such ‘90s albums as “Rhythm Nation 1814” and “The Velvet Rope,” Jackson takes measures not to sound quite as light as she did on the wispy “Damita Jo,” which marked a precipitous drop in sales for the singer, falling short of the million mark.

This time she persuaded her boyfriend, Jermaine Dupri, to join her longtime collaborators Jimmy Jam and Terry Lewis, and Jackson herself, in the crowded “produced by” credit line. Dupri, whose hip-hop/R&B; touch has benefited such artists as Mariah Carey and Usher, brings Jackson into the world of the hip-hop/R&B; hybrid that’s his specialty.

He pairs her with Nelly on the ballad “Call on Me” and with Khia on the opening “So Excited.” He crafts an electro-funk setting for “This Body.”

Though this brings Jackson into the contemporary dialogue, it’s not the cutting-edge, concoction that, say, Timbaland cooked up with her Super Bowl duet partner and wardrobe-malfunction enabler Justin Timberlake.

Dupri exits the album halfway through, leaving the final five songs almost entirely to Jam-Lewis-Jackson. She seems hopelessly drawn to their old-school settings of strings, real pianos and quiet-storm drama.

It’s an odd mix, and it probably means that the kind of comeback that Dupri helped engineer for Carey isn’t in the cards. But the harder edge and her plans to tour suggest that she wants to be back in the game.

So hold the eulogies, for now anyway. It might be a while yet before we live in a world without Jacksons.

Janet Jackson

“20 Y.O.” (Virgin)

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Aiken’s mixed-up remake repertoire

Faced with the follow-up to Clay Aiken’s 2003 debut, it’s hard not to think of Bob Newhart’s classic comedy routine in which he listens on the phone as Abner Doubleday explains his absurdly complicated new game, baseball.

“Is this a rib?” Newhart finally asks through mounting laughter, figuring that the call must be prank by the guys in the office.

The makeup of “A Thousand Different Ways” sounds like the result of a contest among music fans to devise the most ridiculously awful repertoire possible, if the pint-size singer with the mighty pipes decided to remake some love songs from the ‘70s, ‘80s and ‘90s.

How about Richard Marx? Obvious, but perfect. Foreigner! That’s downright evil. Celine Dion? Bryan Adams? Check and check. How about Bon Jovi -- but instead of a hit, get this -- have Jon write a new song. With Desmond Child!

Well, no one is likely to buy this by accident, so it won’t do much harm, and it does have some hits from Dolly Parton, Elton John, Badfinger and Harry Nilsson, so maybe someone will be inspired to look up the originals to see how they sounded before Aiken mowed them down.

Clay Aiken

“A Thousand Different Ways” (RCA)

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Albums are rated on a scale of one star (poor), two stars (fair), three stars (good) and four stars (excellent). The albums are already released unless otherwise noted.