You might encounter this situation if you are using a USB headset that has its own soundcard. This is because USB headset is not supported in C985 and RECentral yet. Please follow the steps below:
Step 1. Open your Control Panel > Sound
Step 2. Set your sound-card as default device in Playback tab.
*please note that you have to set the soundcard's speaker as default for Stereo Mix,do not use your graphic card's HDMI audio (your soundcard's stereo mix will get no audio).
Step 3. Change your tab to Recording, then set your Stereo Mix as default device, and click the Stereo Mix's Properties.
** If you don't have the “Stereo Mix” in your tabs, please make sure you have installed all the drivers for your soundcard, or you can right-click to tick the “show disable devices” & “show disconnected devices”)
Step 4. Change the tab to Listen in properties, and enable the “Listen to this device", then select the “Playback through this device” to your USB audio device, click OK.
After finishing the above steps, you should be able to hear your audio from soundcard and usb device.
Please also note:
a. Connect your soundcard to C985 with 3.5mm audio cable.
b. Select "Audio in" for your audio source in RECentral.
c. If your USB device supports stereo mix, you can try to set your USB device as main, and playback your USB's stereo mix to soundcard.