why is the shutter sound so loud in the nex?

I plan to get the nex 7 and am excited about transitioning over to the system. One negative I found from the web is that the Sony has a loud shutter sound compared to other systems. Check out this video:

http://www.youtube.com/watch?v=_kLeiYJBJZU

Anyone know why the sony shutter sound is so loud? My Canon 5dII actually sounds quieter when I take it to Mirrorless mode. The 4/3 is still loud, but much quieter than the sony nex. Not sure about the Samsung - never heard it. Anyone know how loud that is? It's not a deal breaker but I'm just curious if people like to hear the clickity-clack and sony made it loud on purpose or if it's just a technical thing of the APS-C sized sensor. Wish they could have put some effort to make it quiet since I do a lot of documentary work.

It makes me wonder - everyone always talked about how Leica cameras were quiet. Are Leica cameras really quiet and if so, why are they more quiet than EVIL cameras?

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Rishio
http://www.rishio.com