wrote:
i heard of this ultrasonic device that makes people sick and barf.
anyone know about this?

Other way. You're thinking of infrasound. Most folks have some frequency
usually in the 7-10 Hz range that will cause their abdominal cavity to
resonate. Very weird feeling.

Although there have been some sounds in the audible range that might make
one sick as well... Flora Foster-Jenkins comes to mind....
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."