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Steam Audio pathing in older Source 2 games

This guide does not explain the intricacies or detail how to use various Steam Audio entities. Rather, this guide explains how, in older Source 2 games like Half-Life: Alyx iconHalf-Life: Alyx and Steam VR iconSteam VR, Steam Audio pathing is non-functional by default and requires some extra work.

SteamVR​

Steam Audio pathing is not possible in Steam VR iconSteam VR without a lot of extra work. Namely, it doesn't have a voicegraph called hlvr.pathing or any equivalent. To get pathing to work in SteamVR, a custom voicegraph in a soundstack would need to be created, which is beyond the scope of this page.

Half-Life: Alyx​

Fortunately, Steam Audio pathing does work in Half-Life: Alyx iconHalf-Life: Alyx, and it doesn't require anything very complicated to get working. All it takes to set up a soundevent to use pathing is a few parameters. Here's an example:

	Pathing.example = 
	{
		type = "hlvr_default_3d"
		use_hrtf = 1
		enable_spatial_blend = 1
		voicegraph = "hlvr.pathing"
		sa_enabled = 1
		sa_pathing_enabled = 1
		sa_pathing_mix_level = 1
		vsnd_files = "your/sound/here.vsnd"
	}

To make sure the pathing is actually used, set snd_steamaudio_enable_pathing to 1. By default, it's off.

There are a couple of issues with pathing.

  • The further you move from the sound source, and the more complex that the pathing gets, the more it impacts your GPU frametime.
  • Sometimes, pathing can make a sound completely silent. It's not a good idea to put pathing onto every soundevent you create. In some cases, the sound is weirdly offset. In the worst case, it becomes completely silent.

  • Players - If you don't care about Steam Audio Pathing and want to save some loading time, you can add this to your autoexec.cfg or launch options: snd_steamaudio_load_pathing_data 0

  • Developers - You can save some compile time by not compiling Steam Audio pathing. Nothing in base Half-Life: Alyx iconHalf-Life: Alyx and Steam VR iconSteam VR uses it, and it's a wasted effort if you don't create any soundevents for it.