i've noticed that, actually i think all sound from it seems quieter compared to the original iPad, could be due to the way the speaker is now, instead of being at the bottom it's on the curve.
Also, i will say i don't like how the dock cable sits, it's on the curve and looks and feels like it could easily snap when in there if you aren't careful. would have thought they would have made the dock cable specially for iPad 2 due to that
Edit - I've attached pics so you can see what i mean about the dock. also showing off the grey smart cover lol
I find the keyboard clicks much quieter too.