Here are my findings: Many profiles seem.. rather thin and flat, even with my KRK RP8 monitor speakers at full blast + subwoofer. I can play music through the same speakers and it is loud as get out. Kemper through the same soundcard via spdif is just not very dynamic and loud.
So I discovered that if i adjust the 'Cabinet' Volume way up until my Master (output) led is orange tickling red, my SPDIF sounds much fuller and dynamic.
Now I do remember CK stating this is just an extra volume control and has no special effect on tone but with my system it seems to help a lot without generating clipping. I don't really understand this but back in the 'day', right after the Kemper came out, people recommended cranking the Cabinet volume to get better tone.
What say the forum?