User Data Miscellaneous Groups 

Settings -> Miscellaneous -> Sounds

This sound will play when 

Clipboard Master saves an element 
Specify a sound file here that should be played when Clipboard Master saves an entry.

A collection begins 
Specify a sound file here that should be played when Clipboard Master begins a collection.

The entry is already in the list and will not be pasted 
Specify a sound file here that should be played when an entry is not saved because it is already in the list.

The entry was not pated (e.g. large images) 
Specify a sound file here that should be played when an entry is not saved, i.e. the image is too large. You can specify the max. size of the images to saved in the settings of the clipboard.