A level just isn't a level without some sort of sound in it, whether it be the sounds of computers in a computer room or a CD audio track.
Setting up equipment for noiseless recording
A perfect mixdown for your ingame sounds.
Play an MP3 in your mod's startup screen.
I explain how to prepare sounds so they loop properly in game.
Want to get those NPCs talking? Read on!
To create atmospheric soundeffects, you need to keep several basic rules in mind.
the low tech way...
Custom Sounds Tutorial
Recording and preparing sounds for use in HL. Some aspects also apply to Source.
This is where the file 'sentences.txt' in alvesounds comes up.
How to convert sounds to proper HL format using Goldwave
How to loop those ambient_generic sounds.