Depends on if you are in the web client or desktop client.
In the Web Client, you can specify volume for each media type under preferences.

In the Desktop Client, you have the above as well as the pop and sounds settings in Notifications:

Also, check that the agents without sound are not set for Auto-Answer.
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Robert Wakefield-Carl
Avtex Solutions, LLC
Contact Center Innovation Architect
robertwc@avtex.comhttps://www.Avtex.comhttps://RobertWC.Blogspot.com------------------------------