Edit: Forget the next paragraph sorted. How do I find the OcUK server? I tried the commands and I noticed either Frenchtart or OcUK come scrolling up but no idea how I would join that server still.
"INSTALLATION:
1. Install L4D2 Add-on Support if you haven't got it already (Steam -> tools)
2. Extract the files into your left 4 dead 2 folder*
(Steam\SteamApps\common\left 4 dead 2\)
3. To enable the custom soundtrack type: "snd_rebuildaudiocache" in your ingame console
(takes a while to load, sometimes you must quit through console after loading is complete)
4. Play!"
I used the "snd_rebuildaudiocache" command and left it for a minute or two with the sound looping, and figured it crashed the game. I ctrl-alt-delete and end the l4d2.exe then I tried a single player campaign map and there was no sound. I have tried the command again to give it more time but the progress bar is at 0% and I've tabbed out to type this.
I might have to find the "audiocache" and delete it so steam redownloads it. How long does the command take usually? I've got a quad core 3.8Ghz cpu.
Edit:
Just checked the console and it says:
progress 10000/11267 (88 %)
progress 10100/11267 (89 %)
progress 10200/11267 (90 %)
progress 10300/11267 (91 %)
progress 10400/11267 (92 %)
progress 10500/11267 (93 %)
progress 10600/11267 (94 %)
progress 10700/11267 (94 %)
progress 10800/11267 (95 %)
progress 10900/11267 (96 %)
progress 11000/11267 (97 %)
progress 11100/11267 (98 %)
progress 11200/11267 (99 %)
Touched 11267 cached files
Elapsed time: 104.52 seconds
However its still on the loading screen with progress bar at 0%.
Edit: Nevermind sound is back!