What musical material are you listening to? One thing that myself and many others found is that once you move up to truly accurate speakers your experiences will swing two ways. There is the joyful nirvana from listening to quality recorded music but then there is a lot of very poorly recorded music. Accurate speakers will take the poor part and present it to you accurately....poor.
This is especially prevalent in a lot of rock & pop music from the 80s onward where producers compressed their music to horribly levels to try and present the loudest possible sounding experience. It was fine back then in the day of boomboxes and then the move to really cheap earphones (Yes, I'm pointing at you Apple!) but a lot of music I used to enjoy, I now am less enthused as I can now hear the very audible results of the compression. In a nutshell, the instruments sound all blended and mashed up together instead of being distinct and clear. Your brain adjusts a bit if you listen to a whole album like this but if I'm playing random tracks, the differences between the good and bad material can be very distracting and often disappointing.
Mind you, this doesn't really necessarily equate to what you are describing as extreme sharpness, but it is something to consider.
Another is that once you play something so loud that the amp is pushed beyond it limits, you ears start to get annoyed because the clipping creates audible distortion. It can be very subtle at first. More of an uncomfortable feeling verses a true noticeable distortion. When you get that feeling like you just want to turn something down even though it might not be above your normal comfort zone for volume, it may be clipping.
Again, it doesn't really fit your scenario from your description. However, my point is that there can be a lot of factors.
There are many lists of top notch musical recordings in this board that you can use to test your speakers to rule out some badly recorded music. Check out the Stunning Recordings
thread. Also, grab your db meter again and let us know what peak volume levels you are hitting in both the movies and music.
Other than that, removing/swapping things around is the only way to truly isolate an blatant problem if the gear somewhere is at fault.