This article will cover the various formats and ways audio is used in GoldSrc, from Vanilla to Sven Co-op. This is a collabrative work between The303 & Zode, also credit to the Mad Jonesy's Sven guide.

Part 1: Basic Sound and formats

Main format: Mono WAV only, 11025Hz or 22050Hz
For mouth-moving NPC audio: 8-bit unsigned PCM
For sound effects: 16-bit signed PCM

Music format: MP3, 44100Hz (Note: WON editions only support CD-audio)

Shon — 06/23/2022 5:44 PM Record stereo track at 22hz. Do edits > Limiter l5 r5 -03(precieved loudness), noise reduction, and agrresive (base) eq for best quality. Mix down to mono..

Looping Sounds and Cue Points

Sounds that loop need a embed in the WAV file called a "Cue Point" which tells the game to loop the sound instead of making it play just once. This can be done with several different programs:

Audacity

1) Open your audio file then go to Tracks > Mix Stereo Sown to Mono This will convert to mono if your audio is not.

2) Go to the bottom left corner to Project Rate. Change to either 22050 or 11025 depending on what you need. You need to add a cue point/label to the sound file at the start. Apparently Audacity can do it and they're called "labels" where a lot of people use Goldwave which calls them cue points.

GoldWave

1 (OLD VERSION) Open your audio file then go to Process > Convert To Mono > Mix All Channels. This will convert to mono if your audio is not. (NEW VERSION: this is done at the save as... stage)

2) Go to Effect > Resample. Change to either 22050 or 11025 depending on what you need.

3)If your audio is for looping sounds, then you need to make a marker at the beginning. Tool>Cue Points... or "Cues" icon

4) Save as... and then press the attributes button and set to 16-bit PCM signed for normal sounds and If you need NPC jaw-flap audio set to 8-bit PCM unsigned

WavoSaur

1) Open your audio file then go to Process > Convert To Mono > Mix All Channels. This will convert to mono if your audio is not.

2) Go to Process > Resample. Change to either 22050 or 11025 depending on what you need. If you need NPC jaw-flap audio you will need to go to Process > Resample and set to 8-bit

3)If your audio is for looping sounds, then you need to make a marker at the beginning. Use markers instead: Be sure your playhead is moved to the left all the way and then go to Tools > Markers > Create Marker

Part 2: Sentences

Placeholder text

Part 3: Part 3: Materials

Placeholder text

Part 4: CD Audio

trigger_cdaudio

Half-Life Music MP3 Tracklist

Value 	Mp3 file to play
1 	
2 	Half-Life01.mp3
3 	Prospero01.mp3
4 	Half-Life12.mp3
5 	Half-Life07.mp3
6 	Half-Life10.mp3
7 	Suspense01.mp3
8 	Suspense03.mp3
9 	Half-Life09.mp3
10 	Half-Life02.mp3
11 	Half-Life13.mp3
12 	Half-Life04.mp3
13 	Half-Life15.mp3
14 	Half-Life14.mp3
15 	Half-Life16.mp3
16 	Suspense02.mp3
17 	Half-Life03.mp3
18 	Half-Life08.mp3
19 	Prospero02.mp3
20 	Half-Life05.mp3
21 	Prospero04.mp3
22 	Half-Life11.mp3
23 	Half-Life06.mp3
24 	Prospero03.mp3
25 	Half-Life17.mp3
26 	Prospero05.mp3
27 	Suspense05.mp3
28 	Suspense07.mp3
29 	gamestartup.mp3 (also automatically plays upon launching the game)
30

Part 5: Models

Sounds can be played through NPC models, Weapon Viewmodels, and as well as be spoken using the jaw-flap procedural animation. The way this works is whenever an animation sequence is played and there is a sound even animation specified it will play back the sound.

Note: NPCs game code will precache specified named audio files. New wavs added may not be precached and will not play unless done so in game code. A hacky workaround for this is make an ambient_generic with this sound. Mods like Sven-Coop automatically precache any model sound specified

Model Events for Sound playback

Event	Event description	Extra parameters
1004	Play .wav file	.Wav file path
1005	Play sentence file	Sentence file path
1008	Play named .wav file through voice channel	.Wav file path
1009	Play random sentence group (25 % chance)
	Monster specific events
2001	Monster drops light body
2002	Monster drops heavy body
2010	Monster plays swing or swish sound
	Clientside events for viewmodels
5004	Emit a sound	Wav file path

This list is part of the larger model QC guide. Also reccomended reading is the model guide.

An example of making a sequence that plays a sound through the scientist voice channel (causing mouth animation) using event 1008 on frame 1 of the sequence (wav path is relative to sound folder in base game dir):
$sequence "checktie" "checktie" fps 12 { event 1008 1 "scientist/weartie.wav" }

Part 6: Sven Coop FMOD

Sven Co-op FMOD Supports:
AT9, AIFF, ASF, ASX, CELT, DLS, FLAC, FSB, IT, M3U, MID, MOD, MP2, MP3, OGG, PLS, S3M, VAG, WAV, WAX, WMA, XM

Reccomended to stick with the big 3 formats which is WAV, MP3 and OGG Vorbis. More info on FMOD in the official documentation here.

For 3D model play FMOD via Animation Eventuse event 5004 soundpath. But unlike regular sound entity you have to sure to precache via custom_precache map entity.

Common Sven-Coop Events

Event	Event description	Extra parameters
2003	Plays footstep sound matching the material type set for the map textures (concrete, tile, dirt, metal, etc)
5004	Custom sound format using FMOD system (AIFF, ASF, DLS, FLAC, IT, M3U, MID, MOD, MP2, MP3, OGG, S3M, VAG, WAV, WMA, XM)	custom sound path
5005	Use a custom sprite with paramaters defined via txt file	txt file path (path looks in "events" folder). Example txt file and usage found in "muzzle_example.txt" in the events folder.