The sound of all games has stopped playing

[hando]

I apologize for strange sentences first because my native language is not English.
After changing some settings, the game sound was not output at all.
BGM in the menu is played without any problem. (BGM of various games is selfish)
What could be the cause of the loss of sound only during game play?
Thank you.

[alexkidd]

What "some settings" have you changed?

[hando]

どの「設定」を変更しましたか？

I don't remember all the changed settings.
However, I did the HDMI connection setup exactly as it was on this forum.
I also made some changes to Retroarch's settings, but didn't touch the audio part.

[hando]

I reflashed the image.
As a result, the sound is restored as before.