No Subtitles When Audio Device Is Not Present

Subtitles stop working when all audio devices are unplugged or disabled, meaning that even if it is not being used, an audio device must be present in order to generate subtitles. Audio sliders have no effect - subtitles will not generate regardless of in-game volume level, directional audio, or any other audio settings. Attaching/enabling one audio device caused subtitles to start generating again.