[rescue] SGI Challenge L systems available in Denver

Mike Parson mparson at bl.org
Fri Oct 1 12:57:07 CDT 2004

On Fri, Oct 01, 2004 at 08:39:35AM -0700, Sheldon T. Hall wrote:
>  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.

First time I saw one of those I thought it was kinda weird, but it makes
sense.  Most people don't know about them, they just think it's the AC
running.  I don't know that it's a 'make people work better' thing, more
of a 'cover-up other sounds' thing, they seriously cut down on noise
travel through the building.  I can barely hear people talking in normal
voices more than ~25 feet away, over the cube walls.

Michael Parson
mparson at bl.org

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