I have used ADS speakers for years (L570, L880, L520) and that sound is unique. Recently i have moved on to other speakers like Silverline and Focal. The bass on the ADS always sounded tight and articulate due to their sealed acoustic suspension designs so you will find a difference out there with newer ported speakers like PSB. Someone else mentioned Focal earlier as a recommendation, and i will second that because you already have a NAD amp which should be a good match. I am running Focal 806v's in a bedroom system off a NAD integrated and i think they sound excellent. Good luck in your search but don't be surprised if you stick with the 470's!
Regards,
Paul
Regards,
Paul