(Solving) Sound failure after connecting laptop to smart TV by HDMI connector

I have problem about sound when I  connect my  HP laptop to a smart TV monitor. No sound I got, but display is OK. Some Youtubes show audiences how to solve this problem, for example you have to set playback option, changing sound device. It makes me confused. Since sound panel of Windows 7 is different from Windows 10…

It is very simple to solve this problem.

For windows 7, go to control panel -> sound->Manage audio devices.
– select speaker
For windows 10:
Right click the sound icon at the bottom bar:


Another screen is then  popped up:


Select Playback, then we have another screen shown up:


SELECT SPEAKER/Headphone, click OK.
That is it !