My hinges for my new 2013 13"mba are very loose when open past a 90 degree angle. I found a youtube video of a guy with a similar problem. http://www.youtube.com/watch?v=N3vEfZznH18 My speakers also rattle my keyboard at certain frequencies. It is really noticeable on high volumes, especially on netflix, and lower quality audio. If you play "Hero" in the sound settings at max volume it is very noticeable. Does anyone else notice these problems or do I have a defective model? Later today I am going to exchange it for a new one, and I don't want another one with the same problems if it exist in all of them.