those are called 'germs', i think
and no, i think they aren't the campaign intro noise, nor are they muted by this addon. i think palladium346 meant the campaign intro music, which has intro jingles built into them. but that ain't it

germs, on the other hand...
they play only when;
you come out of the door.
you get a small horde coming for you.

and idk which specific germs make the sound, when you come out of the door, (because there is a lot of them), there might've been an addon somewhere that mutes those?? i don't remember, sorry

Is the campaign intro noise when you get out of a door? cause that is the issue im having, and i havent found a way to mute it

Uhhh... Gallf. Just to be sure, are you confusing the campaign intro noise with the saferoom one? Because those are different

really now? it should cover both l4d1 and l4d2.
that's interesting. what exactly did you hear?
cause i didn't hear anything when replicating what you said. i booted up dead center on the chapter 'mall', and it was dead silence. except for the saferoom music.

to quickly troubleshoot;
open console, type in

play music/stmusic/youhadbetterpray

this command should play sounds. and it will play the intro, that covers all of the l4d2 campaigns.

if you hear it, that means the addon isn't working for you (for some reason).
when i type in that command, it's complete silence.
do you have any saferoom music changing addons? because they sometimes include 'youhadbetterpray.wav' completely unchanged in there as well.
if that is the case, you can try, uhm... checking if they are the cause. disable them and see if this addon works or not afterwards.
you can try moving this addon from the local game files, specifically from 'addons/workshop' to just 'addons'

Is this only for l4d1? cause i tried this will dead center mall and i heard the intro

Probably because it's a type of music file that is cued to play once without interruptions or loops. So all it is told for the intro music is to play... and that's it.

yeah figures, and thank you. the good way to mute sounds is, indeed, to mute it and keep the length just like that. but the file size still may end up very big, when you have to mute a lot of sounds, even if it's just silence.

I figured to experiment. this may be useful to save up storage, using blank.wav

this addon doesn't screech. probably? so far hasn't.

like let's say you mute some survivor voice line, and shorten the length of it. the muted part will be muted. but at the time point, where there's supposed to be something, noise or silence, the part which you shortened; is not present. game compares length of the file and the soundcache's logged length. (I think??)
and then, can't figure out what to play if there's nothing, not even silence. so it screeches. I guess...

however, this, for reasons I don't know, still works, even if it has length shorter than should be. how? idk. maybe because blank.wav is like 1 frame long? or maybe cause it's music? but thanks

Well, first time seeing this. Haven't tested yet, but if I do hear glitched noises at some point during which an intro would have been present, I'll let you know. All I do know is that a set of working mute survivor mods said that the modder went in and muted all the survivor lines individually without changing the file length or other stuff. Just simply set the volume in editing to 0, and it works a treat.

good for you
and well thanks, I'm plentifully relieved

Also, I've been meaning to tell you that I love your custom thumbnails and preview screenshots/videos. I can tell you put a lot of effort into them.

Appreciate the extra effort.
I've been using this mod for a couple of days, and I didn't experience any screeching either. I should try the method in the near future as well. It could come in handy especially when making horde music mods, because you have to silence a lot of audio files for those, and they end up causing the mod file size to be like 194 MB or more.