I am not sure whether you are hearing the same sound quality as I do using my NAD. I usually listen to music without the sub. I find it is not required as my M80's put out more bass then I need all on their own. My kids listen to the sub more often, because they listen to more of the dance/pop type of music, but the sub is not really required, until I start watching movies.

M80 VP150 4-QS8 EP600 Monitor Audio S8 NAD T 773 Anthem MCA3 II Hitachi 57" projection