Garry's Mod has released an update that re-enables the command voice_inputfromfile, meaning HLSS will work in this game once again.

Added a tutorial on how to setup HLSS for Hidden Source.

Added a tutorial on how to setup HLSS for Kreedz Climbing.

There is an easy, temporary workaround to get HLSS working with Garry's Mod again. I imagine it will be fixed soon though. Thanks to the person who emailed me with this information. You can find this workaround in my post here.

The developers of Garry's Mod decided to disable the voice_inputfromfile command, breaking HLSS completely for that game. Discussion about this can be found on the forums.

Added a tutorial on how to setup HLSS for Obsidian Conflict.