adjusting the playback gain will raise the volume for all output including messages, greetings, prompts etc... don't mess with the record gain (it'll mess up the AGC functionality which is what should be used here).
You can use this tool to adjust the output volumen "on the fly" and when you're happy with the volumne you have to write that value through to the registry (the help file shows you how to do that).
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.