Triggering Sounds

In UT, there are several methods used to have sounds in a map that can be triggered. (Nobody has taken the time to write about it for UT2003 yet!)

For one-shot sounds, the best method is probably the SpecialEvent actor, although it doesn't allow volume control. For looping sounds, things are a little more complicated: the problem is making the sound stop.

The methods are:

DynamicAmbientSound

DynamicAmbientSound (description needed)

TriggeredAmbientSound

TriggeredAmbientSound works, but only if bStatic under Actor (UT)/Advanced is manually set to False. There's also YoMammy's custom script on that page, which fixes all of the problems with TAS.

TriggerLight

TriggerLight can be set so a sound is heard when activated, but no light is produced. This works fine with looping sounds.

Set the following properties:

Lighting → LightBrightness to a non-zero number. This will set the maximum volume for the sound
Lighting → LightType to LT_Steady
Lighting → LightRadius to 0 – this is so the light doesn't show
Object → InitialState – Choose a triggering type. See the TriggerLight class page for the list & details

Advantages:

can be set to stop. This means a looping sound can be used.
the sound can be made to fade up or down gradually in the same way that TriggerLight can make the light fade.
the maximum volume can be set with LightBrightness

To make a looping sound play for a set time and then stop, set the TriggerLight's Object.Initial state to "TriggerToggles", and trigger a Dispatcher which in turn triggers the TriggerLight twice – see Trigger Systems for a full explanation of this technique.

SpecialEvent

A SpecialEvent actor can be used to play a sound. Drawbacks to this method:

only one-shot sounds work with this; looping sounds will play continually until the player moves out of range of the SpecialEvent.
the volume can't be specified directly; the sound will play at maximum volume unless you set the TransientSoundVolume property of the SpecialEvent to a value between 0.000 and 1.000. See Actor (UT)/Sound for more info.
If you forget to set the Object → InitialState property it will take you bloody ages to work out what you've missed.

Hidden Mover

This is a dirty trick and best seen in DM-Pressure: the hissing sound made by the pressure chamber is make by two simple cube movers that move in solid space nearby. Their mover sounds provide the noises.