Jamman,
Many of the styles are very busy in variations 3 and 4. I have not yet learned how to adjust the global EQ settings of the keyboard so what follows might not be the entire story. What I am noticing is a a lot of the styles are "Bass" heavy and the programming uses a lot of "ensemble" tones which are sounding very "muddy". My setup is simple - a single Bose L1 Compact using both outputs from the BK-9 into the Bose. Like I said, I have not yet learned how to balance the sounds or deal with the global EQ settings which might make a big difference.

Deane