Looking to upgrade my setup.

Hi y'all! I'm pretty much a rookie when it comes to high end audio. As a musician my ears are pretty tuned but I only recently have gained appreciation to potentials of audio systems. Currently I'm running a pair of Energy cb-20 bookshelves through an entry level Denon reciever. I also have an m and k double 12" sub. The problem I have with it is that the highs seem rather harsh and it is lacking mid bass. I'm hoping to get a system with smoother highs and more punch an the snares and kick drums. Does anyone have any recommendations as far as a new amp and speakers? I really like the sub so I'd like something that wont be drowned out by the m&k beast. Thanks!