When it was released in November 2008, the [article id="1599170"]"Twilight" soundtrack[/article] shot straight to the top of the Billboard albums charts, and by the end of the month, the first of the vampire franchise flicks had opened at #1 on its way to $193 million in box-office receipts. A year later, in its first full week out, the [article id="1624102"]"New Moon" disc[/article] also topped the charts, warming up fans' ears and wallets before the film started its climb toward $297 million in total ticket sales.

Now the [article id="1639068"]"Eclipse" soundtrack[/article] has dropped, and its opening-week numbers -- 144,000 albums sold, good for [article id="1641669"]Billboard's #2 slot on next week's chart[/article] -- represent the weakest debut yet for the franchise's albums. Is it time to panic? Might this be the first glimpse of the decline of "Twilight"? Hardly.

"I don't think the drop-off is anything to be freaked out about," said Keith Caulfield, senior chart manager/analyst for Billboard. "I wouldn't pin it on just one thing. You can chalk it up a bit to album sales declining in general. And it's not surprising that part three sells what it sells in its first week, because as with anything, especially continuing movie franchises or TV series franchises, the interest begins to wane a little as the excitement and the newness dissipates a bit."

Yet it's important to note that with the first two films, album sales and box-office numbers had an inverse relationship. The "Twilight" disc boasts 2.6 million in total sales and "New Moon" ultimately moved 1.1 million discs, while "New Moon" out-grossed its predecessor by $104 million. Further explaining the disparity in album sales is that, unlike the first soundtrack, the "New Moon" disc didn't boast a tune by star Robert Pattinson on its track listing (nor does the "Eclipse" album). Of course, RPattz's smoldering mug is all over the films. The point is, while there is a relationship between album and ticket sales, the two do not move in lockstep.

"A not-perfect comparison would be when people discuss the ratings of 'American Idol' to how well Lee DeWyze or Crystal Bowersox are going to do [selling albums]," Caulfield noted. "The TV show exists in a different world from the artists and their music. If 20 million people tune in to vote each week, not very many of them are actually buying anything. It's the same thing with 'Twilight.' Some people find the music perfectly pleasant in the film, but they're not going to be moved to actually purchase the album for whatever reason."

What they will be moved to do is continue to the support the film franchise -- "New Moon" swept the fan-voted MTV Movie Awards this month -- and buy oodles of theater tickets. "New Moon" is the top-selling pre-release title in the 10-year history of ticketing site Fandango, and there's no reason to expect "Eclipse" to suffer a dramatic drop-off. In fact, 58 percent of "Eclipse" pre-sale buyers tell the site they plan to see the film more than once. After the film premieres, there may even be an uptick in "Eclipse" music sales. Following the November release of "New Moon," Billboard noticed an increase in sales related to interest in the Lykke Li track, "Possibility," which was featured during a key montage in the film and made the Oscar Best Original Song shortlist in December.

"That song really resonated with people, and they wanted to get the album partially for that song," Caulfield said.

Come the June 30 premiere of "Eclipse," the soundtrack might benefit from similar, experience-based fan curiosity. " 'Twilight' has done a really great job of curating the music on the albums, because it so complements the intention of the films and the author's intent," Caulfield said. "People who are interested in 'Twilight' are especially interested in the music because it's all part of one big story."

Have you bought the "Eclipse" soundtrack? How does it compare to the first two? Share your thoughts in the comments.

We'll be live at the L.A. premiere of "The Twilight Saga: Eclipse" on Thursday, June 24. Tune in to Movies.MTV.com at 9:30 ET (8:30 Central) for our red-carpet webcast, and watch us chat with Robert, Kristen, Taylor and all your favorite stars. And don't forget to submit your burning 'Eclipse' questions!

Check out everything we've got on "The Twilight Saga: Eclipse."

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