It didn't do anything to me. Of course, one needs an .ogg decoder to play it and I don't have one.
[link|http://hypertextbook.com/physics/waves/sound/|The Nature of Sound]. Pidgeons can detect sound at 0.1 Hz. Elephants "talk" at 14 - 35 Hz.
I don't think 20 Hz sound requires "extreme caution" at reasonable sound pressure levels. Most consumer speakers won't be able to produce 20 Hz anyway. :-/
My $0.02.
Cheers,
Scott.