When you make a voice or video call, you will need to ensure that the correct audio device is selected. The system will automatically choose one as default so it's only important to follow these steps if you have more than one.
Click the gear icon; the Options dialog box will open
In the left column, click Audio Device.
Use the drop-down list to select your preferred device.
Adjust the volume and test your device. Then click OK.
Note: If you do not hear anything when testing your speakers, make sure that your system volume is turned on.