What will be covered in this guide
In this guide I will walk you through the basics of changing CSS sounds. This will only work with CSS Game Content Fix Addon.
For this guide, I will be replacing the Deagle shot with a Heavy Door Closing sound
What you will need
* = things I will get to later in the guide
The sound file you want replaced (from CSS Content)*
The sound file you want to use instead*
Audacity (for sound cropping/converting) Official Site
Step One: Finding the sound you want to replace
This step should be fairly simple, as the files are very organized.
All sounds are located in C:\Program Files (x86)\Steam\steamapps\common\GarrysMod\garrysmod\addons\CSS_Game_Content*\sound
*note that this folder may be named something different
Since I'm looking for the Deagle shot sound, I'd go to *\sound\weapons\deagle\
The sounds here should be labelled to explain what they are. Weapon firing sounds should be <weapon name>-1.wav, so in this case it's named deagle-1.wav
If you're having trouble finding a sound, you can first navigate to the \sounds\ folder, then using the search function of the file browser.
If you still can't find a specific sound, I'll be happy to help locate it.
Once you find the file, make a copy of it and store it in a safe place (Like in a folder in Documents named "Original_GMod_Sounds") just in case you decide you want the old sounds back.
Step Two: Find the sound file you want to use instead
These can be attained in many ways. Ripping from a YouTube video, a song you have on your computer, a sound from a sound library, a sound of you screaming into a microphone, and anything in-between. Just be careful where you download, and make sure you're sources are trustworthy and always use an adblocker.
The file extension doesn't matter, but it'd help if it's already a .wav
I already have the sound file on my computer, so I wont need to download a new one.
Step Three: Cropping, Fading, Converting and Exporting
This is where we use Audacity. We will be cropping the sound down (if needed), making the sound fade out (so it fits with the other sounds better), and Converting/Exporting the file as a .wav file.
I will make another guide on how to prepare a sound for Garry's Mod at a later date. For now, however, I will only go over exporting.
To export the file, go to File>Export>Export as WAV
navigate to the sound you want to replace and click on it. The name should auto-populate. Click save and, when prompted, confirm replacing the file.
At this point audacity can be closed and, when prompted, you can select to quit without saving.
Step Four: Load into Garry's Mod
Now all that's left to do is start Garry's Mod. The sound should be replaced and ready for use!
I will be more than happy to answer any questions regarding this guide, so don't be afraid to ask! I'll answer as quick as I can!