What entity/trigger I need to activate music?

[Savage Spartan]

Hey how do I start music playing in the backround when like a sequence comes up. Like a battle scene with zombies and music starts playing in backround just like during intense fights in HL 2? What trigger/entity I need/how please expalin thanks!

 

[Unarmed]

ambient_generic.

Create one of those, choose the sound you want and set the "is not looped", "play everywhere" & "start silen" flags and you're good to go. Just fire an output from anywhere you like to the generic with the PlaySound input.