After doing some research into the the weird bug in crash course (where some players have a weird tune played at varying point in the level and also a buggery of the voice comms volume) I've tracked it down to the sound files of two of the custom maps interfering with the new DLC. (looks like the Silent Hill and Detour Ahead)

FIX 1:

go to c:\program files\steam\steamapps\common\left 4 dead\left4dead\addons folder

Delete (or move to somewhere else if you want a backup:)

bblsdetour.vpk

Restart steam.

---- If you still get the annoying sounds problems repeat the above steps but remove the silent hill maps: silenthill.vpk

If you still get the annoying sound problems after the above, please post here...



FIX 2 (try Fix1 first if you can)

WARNING: this fix will redownload some file, it might take some time

go to your c:\program files\steam\steamapps\common\left 4 dead\left4dead\

Rename 'Sounds' folder to 'Sounds-Backup' (or another name).
Next go to the 'maps' folder and rename the 'soundcache' folder to soundcache-backup (or another name)

Then in steam, Right click for properties on L4D and force a file check - steam will redownload the sound files.


It appears some sound files in the custom maps have the same manifest resource names as the crash course DLC..

cheers,

MonkeyFiend

Unconfirmed reports that the dead city maps might also be a problem, let me know if deleting the above 2 fix it or not or whether removing 'deadcity_campaign.vpk' fixes it. thx.

is this the weird horns that come and go sporadically?? like a sort of air raid siren

i tho they were there to assist SI because it downs out thier noises allowing a sneak attack without giving away positions etc?

or is there another conflict? i dont have many custom maps

just waiting for dawn of the dead remake and yami! <3