[rescue] SGI Challenge L systems available in Denver

[Sheldon T. Hall]

 Thomas Gallaway says ...

> Some girl I know  told me that big highrises are pressurised
> (what makes
> sense). But also she told me they where producing some kind of low
> frequency ambient sound in the building to make people work
> better? Is
> this true?

Modern highrise buildings have all sorts of interesting stuff.

Sometimes the buildings are slightly pressurized to keep them cleaner and to
prevent infiltration of uncontrolled outside air.  The stairwells have
_massive_ automatic pressurization systems as a smoke-control measure in
case of fire.

It's not "low frequency" sound, but "low amplitude."  It's common to have
loudspeakers above the drop ceiling broadcasting white noise at a low volume
level, to cover up the other noise in the building.

Then there's the water system ...

-Shel