How do you get the hidden music in Call of Duty Black Ops

In zombies, there are three items... In five, its 3 red telephones, Kino Der Toten has 3 parts of a rock (it faintly glows), and in Ascension, its three teddybears with sickles... In order to use them, hold the X key (on the xbox)... when you collect all three, then a song will start playing