I like to play l4d2 with the music turned off.
This means I never hear the normal horde is starting sound
for horde events that trigger as you are moving through the map.
I know sourcemod scripting and can play a sound,
but don't know how to detect when a horde is starting.
This isn't a main horde event like when you start a final.
I am looking for the horde events that trigger as you are moving through the map.