I came across a wonderful TED talk by Julian Treasure about the influence of poor sound design on our built environments and how it affects our health, our social interactions and our overall production and wealth.
I find it very interesting that our focus on making healthier spaces via LEED and other programs is missing (apparently) a crucial piece of design for occupants' health and well-being. The impacts Treasure demonstrates in his video are astonishing and he uses recorded sound to great effect in demonstrating the problems facing these built environments and the associated costs (both in loss of productivity and costs to remedy).
A great video and, as with all TED talks, very brief. Please do take a minute to watch.
Update: the video is not appearing on the blog for me, so if you can't see it, here's the link: http://www.ted.com/talks/julian_treasure_why_architects_need_to_use_their_ears.html