Make sure that Windows is sending audio to the HTC-VIVE-C audio device.

1. Press the Windows key
2. Type: sound
3. Select Sound in the Control Panel
4. Under the Playback tab, right-click the HTC-VIVE-C audio device and select Set as Default Device
5. If sound still isn't sent to the Vive, disable other enabled audio devices

If this fails, go back into the Playback tab and try setting the Speakers USB audio device as the Default Device. Sending audio via USB may add extra latency to sound playback. We recommend using the HTC-VIVE-C HDMI audio device when possible.

1. Click on the "volume icon in the task tray
2. Locate the HTC-VIVE-C (or USB Speakers) volume
3. Set volume to 50%

1. Click on volume icon in the task tray
2. Under HTC-VIVE-C (or USB Speakers) volume slider, click Mixer
3. Locate the application's volume slider and set to at least 50%

Click the X to close SteamVR, then launch it from Tools in your Steam library.