Napstar is a wrong example because who ones the copywright is obvious. The artist paid a fee for the songs or wrote the songs themselves.
The Xmas disk from Technote also. If they paid royalties to the owners of the rights of the Xmas songs for using them, then there is a copyright.

But when they or sombody else even one of the members of this site make a e.g. a sounddisk only by changing some parameters of the keyboard than there is no copywright. Only you could pay a kind of fee for there efforts to do this. Because all the things to get to that sound are free accessable for everyone who have that kind of keyboard.
Even by making a style. As said before. A foxtrot is a foxtrot. And look at the naming of some styles in the KN6000. "Ribon"
"Carpenter" which have some massures and the feeling of that particular song or group.

rgds
Wim