Soundscripts

Source Engine

Source 2

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Soundscripts contain sound entries or game sounds that are used to wrap Source-specific playback instructions around WAV or MP3 files. A sound entry or game sound can define the meaning of a sound to NPCs, its pitch and volume, how far away it can be heard from (attenuation), and can be used to randomize which precise sound file is played. Operator stacks (in all games since ) can be used to define even more complex behaviors.

Soundscripts are loaded on the server only from:

• scripts/game_sounds_manifest.txt
• maps/<mapname>_level_sounds.txt (not in )

All filepaths within a soundscript are relative to the game or mod's sound/ folder.

playgamesound <entry> is a console command that one can "browse" and play the available sound entries of a game with.

Example

entry.name
{
    channel    CHAN_AUTO
    volume     VOL_NORM
    pitch      PITCH_NORM
    soundlevel SNDLVL_NORM
    wave       common/null.wav
}

If a value has a space or tab character within it, it must be wrapped in "quote marks".

Commands

Wave / Rndwave

Filename of the sound to play. All file paths can be preceeded with one or two sound characters, see below.

wave common/blah1.wav

You can also have the engine pick from a list of random files. A given sound won't repeat until all of the others have played. Note that the random choice is decided by the server, not the client.

rndwave
{
    wave common/blah1.wav
    wave common/blah2.wav
    wave common/blah3.wav
}

Note:The sound file MUST be in a folder within the sound\ folder. So sound\folder\sound.wav will work, while sound\sound.wav will not.

Volume

A number between 0 and 1, where 1 is the sound's original volume. VOL_NORM will insert your mod's default volume, which will probably be 1.

To have a random numeric value chosen every time the sound plays, type a lower bound and a higher bound, separated by a comma. Example: volume 0.4,0.6.

Pitch

Any number between 0 and 255, where 100 is the sound's original pitch and 255 is very high.

• PITCH_LOW = 95
• PITCH_NORM = 100
• PITCH_HIGH = 120

To have a random numeric value chosen every time the sound plays, type a lower bound and a higher bound, separated by a comma. Example: pitch 90,110.

Channel

Channels are used to categorize sounds in a way that NPCs, and game logic in general, can understand.

Confirm:There is a limit of 256 channels total: 224 Static, 32 Dynamic that can play at any given time.

Exceeding this will result in a channel allocation error, preventing sounds from playing.

Value for channel	Description
CHAN_AUTO	Default, generic channel.
CHAN_WEAPON	Player and NPC weapons.
CHAN_VOICE	Voiceover dialogue. Used for regular voice lines, etc. Note:If sound with this channel is emit by an entity that has the "mouth" attachment, the sound comes from it.
CHAN_VOICE2	Additional voice channel. Used in for the announcer.
CHAN_ITEM	Generic physics impact sounds, health/suit chargers, +use sounds.
CHAN_BODY	Clothing, ragdoll impacts, footsteps, knocking/pounding/punching etc.
CHAN_STREAM	Sounds that can be delayed by an async load, i.e. aren't responses to particular events. Confirm:This won't make the sound actually stream; use the * path prefix for that, see below.
CHAN_REPLACE	Used when playing sounds through console commands.
CHAN_STATIC	A constant/background sound that doesn't require any reaction.
CHAN_VOICE_BASE	Network voice data (online voice communications)
CHAN_USER_BASE+<number>	Custom channels can be defined here. Allocates a channel for the desired sound entry.

Channels can also be specified by a number, corresponding to the enum in the engine. For example -1 will be CHAN_REPLACE.

Soundlevel

The sound's attenuation; how fast it drops away. The engine starts running into trouble below 60dB.

The following list contains all default sound levels, their attenuation value, real world examples, and in-game examples. All values and real world examples were taken from src\public\soundflags.h.

It is possible to pass a literal number value ("150" as opposed to "SNDLVL_150") and freely choose any number between 0 and 255. Games tested:

Value for soundlevel	Attenuation Value	Real World	In Game
SNDLVL_NONE	0	Everywhere	: Music disconnected from environment (Ex: checkpoint music, credit music, mob music)
SNDLVL_20dB		Rustling leaves
SNDLVL_25dB		Whispering
SNDLVL_30dB		Library, dishwasher
SNDLVL_35dB
SNDLVL_40dB		Moderate rainfall
SNDLVL_45dB		Refrigerator
SNDLVL_50dB	3.9	Average home, heavy rainfall
SNDLVL_55dB	3.0		: Digital alarm clock in C8M1_Apartment.
SNDLVL_60dB SNDLVL_IDLE	2.0	Normal conversation, clothes dryer
SNDLVL_65dB	1.5	Washing machine, dishwasher
SNDLVL_STATIC	1.25
SNDLVL_70dB	1.0	Car, vacuum cleaner, mixer, electric sewing machine	: Moustachio whack smash and pop-up, tv static, whacked piano
SNDLVL_75dB SNDLVL_NORM	0.8	Busy traffic	: Various doors, swarm of flies, Lilpeanut audible, bullet impact on wood.
SNDLVL_80dB	0.7	Mini-bike, alarm clock, noisy restaurant, office tabulator, outboard motor, passing snowmobile, police siren	: Jukebox, music spitter spit pile as source.
SNDLVL_TALKING			Valve's chosen dialogue attenuation
SNDLVL_85dB	0.6	Average factory, electric shaver	: Moustachio strength attract, big fire after airliner crash in C11M5_runway
SNDLVL_90dB	0.5	Screaming child, passing motorcycle, convertible ride on freeway, hair dryer	: Moustachio strength attract, gas can bursting
SNDLVL_95dB			: Mounted Machine Gun
SNDLVL_100dB	0.4	Subway train, diesel truck, woodworking shop, pneumatic drill, boiler shop, jackhammer	: Music coop player in danger AKA tags (ledge hanging, pinned down by SI), Elevators.
SNDLVL_105dB		Helicopter, power mower
SNDLVL_110dB		Snowmobile (drivers seat), inboard motorboat, sandblasting, chainsaw	: Boomer alert close, Van in C11M4_Terminal.
SNDLVL_120dB		Car horn, propeller aircraft, concert	: Boomer alert, Indoor fire in C1M1_Hotel, Fireworks in C2M5_Concert, Rain in "Hard Rain" campaign.
SNDLVL_125dB			: Boomer alert far
SNDLVL_130dB		Air raid siren, fireworks	: Carousel music during crescendo event, C5M2_park perimeter alarm.
SNDLVL_GUNFIRE	0.27	Threshold of pain, gunshot, jet engine
SNDLVL_140dB	0.2	Airplane taking off, jackhammer	: Flock of crows, Lowering bridge in C5m5_Bridge, APC engine.
SNDLVL_145dB			: Wandering witch music ("lost little witch")
SNDLVL_150dB	0.2	Smithing hammer	: Concert music, parade music, zombie choir, Boat Horn
SNDLVL_180dB		Rocket launching

Operator stacks

Main article:  Soundscripts/Operator Stacks

Portal 2 engine branch introduced Operator Stacks, which are a system used to add complex behavior to sounds, extending soundscripts. Outside Portal 2, they are supported in:

The keyvalues soundentry_version 2 and operator_stacks are characteristic. Example:

VFX.LightFlickerEnd 
{
	channel		CHAN_AUTO
	soundlevel	SNDLVL_105db
	volume		1.0
	rndwave
	{
		wave	"vfx/light_flicker/light_flicker_end_01.wav"
		wave	"vfx/light_flicker/light_flicker_end_02.wav"
		wave	"vfx/light_flicker/light_flicker_end_03.wav"
		wave	"vfx/light_flicker/light_flicker_end_04.wav"
	}

	soundentry_version 2

	operator_stacks
	{
		start_stack // applied when the sound begins
		{
			import_stack 	"P2_exclusion_time_blocker_start" // defined in scripts/sound_operator_stacks.txt

			// We are now extending/configuring "P2_exclusion_time_blocker_start"
			// which contains an operator with the exact name "block_entries" whose values we will now override:

			block_entries // prevents another sound from playing
			{
				input_duration	0.25					// seconds to block for
				match_entry		"World.LightFlickerEnd"	// the sound entry to block
				match_entity	false					// only on the same entity that this sound is playing from?
			}
		}
	}
}

Sound characters

The first two characters of a sound's filename are scanned for the following:

Symbol	Name	Game/branch	Purpose / Notes
*	CHAR_STREAM	all	Streams from the disc, get flushed soon after. Use for one-off dialogue files or music.
#	CHAR_DRYMIX	all	Bypasses DSP, becomes affected by the user's music volume setting (snd_musicvolume). The latter part also requires the sound to be non directional (soundlevel of 0). Note:(in all games since ) Operator stacks can achieve this, too, making this character not necessary, see Soundscripts/Operator Stacks#Music. Warning:Using this character on a sound entry utilizing an operator stack with an update_stack where the volume is zeroed out, whether by the update_stack or by the sound entry itself (volume 0.0), will cause an update_stack loop. Not only does this have negative performance implications, the sound will consume an audio channel until the loop is interrupted or the sound is stopped. [Confirm]
@	CHAR_OMNI	all	Non-directional sound; plays "everywhere", similar to SNDLVL_NONE, except it fades with distance from its source based on its soundlevel.
>	CHAR_DOPPLER	all	Doppler encoded stereo: left for heading towards the listener and right for heading away.
<	CHAR_DIRECTIONAL	all	Stereo with direction: left channel for front facing, right channel for rear facing. Mixed based on listener's direction. Todo: Relationship with CHAR_DIRSTEREO in Counter-Strike: Global Offensive?
^	CHAR_DISTVARIANT	all	Transition distance is hard-coded, see below.
)	CHAR_SPATIALSTEREO	all	Spatializes both channels, allowing them to be placed at specific locations within the world; see below. Note:Sometimes ( must be used instead, see below.
}	CHAR_FAST_PITCH	all	Forces low quality, non-interpolated pitch shift.
$	CHAR_CRITICAL	Up to	Forces sound to be cached at a fixed point in memory. Note:Only affects Original Xbox, which streams all audio regardless of * unless marked as critical. (removed since )
!	CHAR_SENTENCE	Since	An NPC sentence.
?	CHAR_USERVOX	all	Voice chat data. You shouldn't ever need to use this.
&	CHAR_HRTF_FORCE		Indicates wav should use HRTF spatialization for all entities (including owners).
~	CHAR_HRTF		Indicates wav should use HRTF spatialization for non-owners.
`	CHAR_HRTF_BLEND		Indicates wav should use HRTF spatialization for non-owners, blended with stereo for sounds sufficiently close.
+	CHAR_RADIO		Indicates a 'radio' sound -- should be played without spatialization.
$	CHAR_SUBTITLED		Indicates the subtitles are forced.
%	CHAR_MUSIC		Indicates main menu music.
(	CHAR_DIRSTEREO		Indicates directional stereo wav (like doppler).

For example:

• )weapons/m4a1/m4_shoot.wav
• *@npc/vo/announcer/specialoffer.wav

Spatial stereo

Adding ) in front of a stereo sound name in the soundscript such as )weapons/m4a1/m4_shoot.wav tells the sound engine that it is a spatialized sound; this allows the sound to emit from a specific location within the world. When not used, stereo sounds play in a fixed 2-channel orientation and cannot be panned to simulate a location. Single-channel files do not require ) before the filename and will be spatialized automatically.

Soundscapes

Soundscapes have special needs. Stereo wave files used in PlayRandom require that ( is placed before the filename. PlayLooping still uses ) but ( will spatialize the two channels separately for an alternate effect; ( sounds more environmental, but the exact nature of this behavior is unknown. Generic soundscripts can sometimes use ( to gain the same stereo spatialization that occurs in PlayLooping.

Confirm:Is this ( stereo-spatialization behavior present in all engine branches? Some preliminary testing reveals it may be absent from Garry's Mod.

Example

wave ")ambient/stereo_alarm.wav" // Typical usage in a standard soundscript But in soundscapes: playrandom { time 33,68 volume .6,1 pitch 90,105 position 0 rndwave { wave "ambient/mono_siren.wav" // Mono files are always spatialized properly wave ")ambient/stereo_alarm.wav" // WRONG; sound will not be spatialized wave "(ambient/stereo_siren.wav" // Correct; sound will be spatialized normally } } PlayLooping { volume .6 pitch 100 position 0 wave ")ambient/stereo_siren.wav" // standard spatialization; both channels originate at same location //wave "(ambient/stereo_siren.wav" // stereo spatialization; one of the channels is spatialized alternatively }

Distance variance

Adding ^ in front of a sound name, such as ^weapons/explode3.wav tells the sound engine that it is a distance based sound. The left channel of the sound file is the 'near' sound that will play when the sound originates close to you, and the right channel is the 'far' sound that will play when the sound originates far from you. If the ^ mark is not used in the soundscript, the sound is treated as stereo with no directionality or distance. This is a different feature than the soundlevel property to control attenuation. This distant variant feature allows you to play two different sounds (but using only one file) and crossfading between the two depending on how far away the sound originates.

The fade distances are hardcoded to begin at 240 world units and end at 1320 world units, and cannot be changed in custom maps or mods.

See also

• ambient_generic
• Soundscape
• Left 4 Dead Soundscripts
• Podcast 17 Mike Morasky Interview - Discussion about audio production and insight into the evolution of the sound system. Archived from the original.

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• src\public\soundflags.h
• src\public\soundchars.h
• scripts\game_sounds_header.txt
• scripts\game_sounds.txt