no you dont have to listen to music at high levels to hear the difference. your speakers are fine, although i would suspect most people wouldnt know that those are polk. rt55 are good fronts, which is what you are mostly using for music. maybe you dont have the 950 setup ideally. i dont have a 950 so i couldnt help you in that direction. but there are lots of settings, crossovers, etc. that impact the way a system sounds. a lot of times it is hard to tell the difference in the way something sounds. if you like the music, you usually would say it all sounds good.... to tell the differences you have to kind of separate yourself from the music and critique it against what youve heard elsewhere.