Home theatre and Musical Experience

Current system driven by Denon avr 2800 and does anadequate job for ht but only mediocre for music. Have been planning to add a power amp for the mains driven by the pre outs from the denon. Hoping to find the sound. Current system is muddy on music until I go to higher spl's. Want the dynamics and airiness that I am missing at lower spl's. Looking for what you would hear at a nice jazz club where the musical presence is there without the volume. Auditioned B&w naut805 and found the same thing so have turned to possible amp upgrade. Am I on the right track? Anyone gone through this upgrade and had success? Any amp suggestions? Feel sure this will lead to future upgrades just want to start where I will hear and feel a difference and go from there.
Thanks
Steve