Enlarge Image Beaulieu, Madeleine (SEA-WSW)

Sprint is bringing on a new DJ.

The nation's fourth-largest wireless carrier is adding Napster, formerly Rhapsody, as a music-streaming partner. The move follows Sprint's partnership with rival service Spotify in April 2014.

It doesn't offer Sprint customers a special deal or preload Napster's app on their phones, but it combines billing onto the phone owner's mobile plan.

The alliance is most meaningful for Napster, more so than for Sprint or Spotify. Napster, which is far behind Spotify in number of subscribers, gains greater access to Sprint's 60 million customers. For Sprint, the partnership may mean some beneficial tweaks in terms, but the deal doesn't break new ground. Music partnerships along these lines are standard for carriers today, leaving rival services to elbow each other out whenever a big contract comes up for grabs.

In the last two years, Spotify has relied on its unique free-listening option as a powerful tool to recruit new members, rather than the carrier partnerships that propelled its early years of growth. Napster has taken up the mantle of pursuing partnerships to grow.

Spotify said in September that it has 40 million paying subscribers, versus Rhapsody's 3.5 million as of last December.

Under the new Napster deal, Sprint phone owners will get a month-long free trial of all-you-can-eat, on-demand tunes -- the same deal available to anyone signing up to Napster for the first time -- before being charged the regular rate of $9.99 a month through Sprint's bills. The app won't come preloaded with Sprint phones, but Napster and Sprint market themselves together and Sprint sales reps will teach customers about the Napster option.

Plus, Sprint prepaid brands BoostMobile and Virgin Mobile added Napster to their data-free list. Customers using Napster can stream unlimited music without it counting against their high-speed data limits.

Also Thursday, Napster announced three other partnerships. Headphone maker Even is making a high-quality-audio test for Napster's iOS app. Listening through any headphones, members hear a series of tones and sounds to figure out optimal listening levels for their particular ears and headsets. In Germany, airline technology company Lufthansa Systems and Napster will offer music and audiobooks to passengers, and retailer Aldi will continue working with Napster.

Correction at 8:25 a.m. PT: Sprint is continuing to work with Spotify. An earlier version of the story said Sprint was dropping that music service.