External EQ would be last thing I'd do. First, check that the setup hasn't set any silly defaults... eg. Try Dynamic EQ = ON; Dynamic Vol = OFF.
The dynamic volume was in Med setting.
There's 4 settings Light Med Heavy and Off
As I selected the lesser, down to off beginning at Heavy
the volume increased significantly with each lower Dynamic Vol setting
and became less muddy.
It was very very dull, muddy garbage as I hooked up my NAD it became
all the more apparent I was dealing with an inferior setting,
and component
when using the Denon as compared.
Actually, I wouldn't recommend external EQ full stop. It's really been rendered surplus to requirements by Audyssey MultEQ and/or the manual EQ (if you prefer) available on the X4000. However, if you just enjoy the tweaking around with it, that's your prerogative.