Hypersonic Effect of High Frequency Components beyond the range of human hearing

this is to answer Yannick's question about why we should be worried about High Frequency partials if they are beyond the range of human hearing. I didn't give
an adequate explanation so I did a quick lit survey:

http://jn.physiology.org/cgi/content/short/83/6/3548

Check this out...particularly looking at how high frequency components have been known to affect brain electrical activity and blood flow...perceived yet not heard...same
with infrasonic frequencies.

cls