Permanently remove map background sounds

[Jicyphex]

My map is based on Korhal Textures, it was something else before but I replaced the theme to Korhal (Map> Map Textures). So far so good but I keep hearing those sounds in the background (traffic, cars etc.) that you hear in the Tychus-Odin mission.
How can I permanently remove those sounds without interfering with my model/actor sounds? Do I really have to look for every single sound that is linked to this map in the sound editor?
I hope there is just a trigger for that.
Thanks in advance.

 

[Dr Super Good]

Change the "Ambience" field for the "Terrain Types" catalog entry "Korahl (Urban)".

 

[Jicyphex]

Not sure what you mean, at least I couldn't find it in my first 2 minutes of endless searching buuuut..
"Sound - Mute Ambient channel for (All players)"
worked just fine.

 

[Dr Super Good]

Under data editor... No need for triggers.

Catalog -> Terrain Types
Entry -> Korahl (Urban)
Field -> Ambience

Change that to a different ambient to change the sound. Setting it blank should cause no ambience to play.