A user asked how to adjust the overall audio volume of a sample set in Hauptwerk.
Before proceeding, you should know that in general the sample set creator sets the default audio level of a sample set so that when tutti is used and fat chords played, it does not clip (Wiki explanation of the phenomenon) the audio stream. When the organ is large, this may result in single stops sometimes too quiet.
The best solution is to use an external amplifier to amplify the volume of the result to the desired level.
However, if you never use tutti (or similar loud registrations), you can increase the volume of the sample set in Hauptwerk. How?
Go to menu, View --> Large floating control panels --> Audio, MIDI and performance
Then, on the panel, adjust the "Audio" to any desired level. The default level is -10dB, you can try -8 dB, or -6 dB, or anything you like.
However, remember, that with some fat chords and loud registration, you can get audio clipping! That is the audio meter going to the red zone. It is good to avoid this happening, because the sound gets distorted, and in the worst scenario, the clipped sound can damage the tweeter of your speakers. The default value -10 dB is the safe level.