In the control panel sound , sound effects allows to turn on or off

Thanks.
Is there a possibility to completely delete the sound effects?

I don't know if there is. But I see there are 15 things in sound effects to control

If you want to destroy all the sound effects do this:

and type your password.
Then through nautilus go to: /usr/share/sounds/
and then cut the folder "deepin" to your home folder, to make a backup.

Having listened it to the startup sound for a bit, I can understand why people would want to stop it!  Although pleasant enough, it's too damn loud.  Another sound-related problem invloves the volume control on the Dock.  What is the point of it issuing a 'blip-blip-blip-blip' sound as you adjust the volume up or down, particularly as if there is music being played, it will be superimposed over the music!  This is just plain daft.

I agree the startup sound is too loud. I turned off the blip-blip sound under sound effects adjust volume to off

You're right, well, I'm not new to Linux, nor to Deepin, but I'm new to the version 15, I didn't know that there was such a package. Thx though!

The more you know...

you can of course customize the sound theme, using audacity or deleting files.