Sound sequence

A sound sequence is as the name implies a series of sounds that are played sequentially. The most common sound sequences are used for sector movement, such as doors opening or platform lowering: these typically have a sequence made of a "start" sound played once, followed by a "moving" sound played on a loop until the sector stops moving the a "stop" sound is played once.

However, sound sequences can be used for other purposes. Heretic uses sound sequences for its ambient sounds, and they can be scripted with ACS functions such as SoundSequence and its variants. The console command playsequence can be used to test sound sequences.

To override a sector's default sound sequences, use the UDMF soundsequence property with the sound sequence name, a sound sequence thing with the relevant sequence index, or the Sector_ChangeSound special with the sequence index. For polyobjects, use the sound parameter in Polyobj_StartLine or Polyobj_ExplicitLine.

Note that a sector has only one sound sequence. If a sector behaves both as a door and a platform, it will use the same sound sequence name (in UDMF) or index (with sound sequence thing) for both its door movements and its platform movements. Sector_ChangeSound can be used to attempt to work around this limitation, setting a door sound before running a door special and a platform sound before running a platform special.