Disable sound on the shell maps.

OpenRA.Mods.Common/Traits/World/MusicPlaylist.cs

@@ -32,6 +32,9 @@ namespace OpenRA.Mods.Common.Traits
 			"It cannot be paused, but can be overridden by selecting a new track.")]
 		public readonly string BackgroundMusic = null;
 
+		[Desc("Disable all world sounds (combat etc).")]
+		public readonly bool DisableWorldSounds = false;
+
 		public object Create(ActorInitializer init) { return new MusicPlaylist(init.World, this); }
 	}
 
@@ -55,6 +58,9 @@ namespace OpenRA.Mods.Common.Traits
 			this.info = info;
 			this.world = world;
 
+			if (info.DisableWorldSounds)
+				Game.Sound.DisableWorldSounds = true;
+
 			IsMusicInstalled = world.Map.Rules.InstalledMusic.Any();
 			if (!IsMusicInstalled)
 				return;
@@ -220,6 +226,8 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			if (currentSong != null)
 				Game.Sound.StopMusic();
+
+			Game.Sound.DisableWorldSounds = false;
 		}
 	}
 }