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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 (for some reason)
  • 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.

Having said all of that, here are a couple of tips:

  • 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.