Interesting observations. How are you streaming 192K files?
I've been playing around with my iPad and audio streaming. Using the Vaunix hub in the middle to allow the iPad to work with it, I had it almost streaming 192k. The AP1 showed 192k but the music was distorted. Going back to 96k files, they sound better streamed through the iPad than direct from my MacBook Air. Not sure if the "better" is actually better or not, but the binaural Amber Rubath album sounds gentler and more delicate from the iPad, but more forward and aggressive with the MacBook Air. It's quite maddening. Would be great if the AP1 worked with 192k from the iPad though!
I'm streaming them using the iTunes Sharing feature. Would be fantastic if I can get this working. Apple has likely done a silent update of this feature to allow this, but the AP1 doesn't like the output.