Here's how to turn off the browser notification sounds from #Mastodon.
Go to your Notifications tab, then click the settings button to access the notifications settings. Be sure to scroll down to see all the notification options available.
Honestly, this was tricky find for me. Especially since there's a totally different "Notifications" set of options in "Preferences". That seems like a more intuitive spot to include the notification settings & how #notifications display. #feditips