Unfortunately have just left my apartment so can’t confirm visually checking but it should be located as follows……
/Users/{username}/Library/Application Support/Preferences/com.audirvana.Audirvana-Studio.plist
The library folder is hidden by default. Just go to your home folder then right click in the finder window and “show view options”. Midway down the view options dialog there should be a checkbox to “show library folder”. Then just go to Library and then Application Support etc as detailed above until you find the preference file.