DownSights writes “As is tradition, the new Firebase Z map contains a musical easter egg as well. There are three cassette tapes scattered around the map. Upon collecting all three tapes, the music starts playing similar to how it was for Die Maschine.
In this guide, we show you all three locations of the tapes. You can find two tapes at the spawn location and one more at the firebase. Note that you must have turned on the power before doing this easter egg. Feel free to check out our power and pack-a-punch guide for Firebase Z.”
Source: N4G PC How To Do The Song Easter Egg On Firebase Z (All Cassette Locations)