With the upgrade of computer hardware, the interface of the external monitor on the notebook is not only a kind of VGA.
You may also be able to connect to an external display device by using the HDMI line shown below.
Then we will find that through this interface to connect to the external display, when playing video audio without the sound.
This is because the HDMI line can transfer both images and sound, so the system will be use the external monitor playback sound by default, and just external devices (such as monitors, projectors) is not with the sound playback function, so we could not hear the sound.
So we’re going to use the following steps to set the default playback device to the computer’s speakers:
1.Right-click on the speaker icon and select “Playback Devices”
2.Right-click on “Speaker/handset”–“set as Default Device”
When the settings are complete, the work of playing the sound will be returned to the speaker on the computer.