Twitter has team up with soundcloud and itune to provide music in tweet. This was made possible after audio card feature has been enabled on their system and It will be available on iOS and Android devices
“With a single tap, the Twitter Audio Card lets you discover and listen to audio directly in your timeline on both iOS and Android devices,” Foo fighters were the first to expliot this feature by tweeting out their first song in their latest album.

"All through your listening knowledge, you can dock the Audio Card and continue listening as you keep on browsing inside the Twitter application." The audio card open up a full screen sound player in case of soundcloud's and complete it with whatever artwork that has been uploaded to soundcloud for it by the creator

Guetta tweeted a link to a new remix of his dangerous song and chance the rapper followed with new single no better blues link

“We’re just beginning to test the Audio Card and plan to make it available to more partners and creators in the future so that many more musical artists and creators will be able to share exclusive, in-the-moment audio to millions of listeners on Twitter,” wrote Slatter. Just an hour after the partnership with soundcloud, Twitter revealed also the partnership with apple that its using the card for it itune store.

http://www.josphatinfo.com/2014/10/intweet-audio-on-twitter-with-soundcloud-and-itune.html