Emanation Shielding with Music

[Tyler Durden]

That may answer why they use white noise as the cover: The frame and other
components transmit enough vibration as to make a vacuum approach not very
effective.

I like the bullet proof glass piece. At least these folks are under no
illusion as to the value of their services.

-TD

> Date: Tue, 21 Oct 2008 17:31:08 -0400
> To: cypherpunks at al-qaeda.net
> From: jya at pipeline.com
> Subject: RE: Emanation Shielding with Music
>
> Thanks for the comments here. Two responses received from
> elsewhere:
>
> No. 1
>
> Comments concerning TEMPEST and Laser Mic probes of windows
> and fenestration.
>
> 1. A high security internal and external window install would typically
> consist of two layers of 0.75 inch glass with a high lead contact.
> Exterior facing walls may have ballistic glass of varying thickness,
> again with a high lead layer.
>
> 2. Music IS NOT introduced between layers in a high security
> application. However, WHITE NOISE is introduced; sourced
> from a very secure high entropy white noise generator whose
> output is constantly monitored and mathmatically analysed in
> order to detect any unacceptable departure from the expected
> levels of entropy.
>
> __________
>
> No. 2
>
> US patent 6,285,773 discloses a speaker designed specifically
> for use in double glazing.
>
> Also interesting, five US patents assigned to CPFilms Inc.
> (7,405,872, 7,295,368, 7,177,075, 6,891,667, and 6,859,310)
> contain this golden nugget:
>
> "A flexible transparent sheet made in accordance with this
> invention may also be used to minimize acoustic transmissions
> from a building by carefully applying the film to the window with
> an adhesive while making certain that no visible air bubbles are
> formed between the flexible sheet and the glazing of the window.
> The term "visible air bubbles" used herein means air bubbles
> which are visible without any magnification (i.e., visible to the
> naked eye). It has been discovered that when the transparent
> flexible sheet lies over an air bubble, the flexible sheet behaves
> like the diaphragm of a loudspeaker. This causes unwanted
> transmission of sound waves. Avoiding these bubbles minimizes
> the transmission of the sound waves through the window."
>
> __________
>
> We add that the glazing must be acoutically isolated from its
> frame. Metal frames of windows and doors are very effective
> transmitters of signal (as well as temperature), either those
> received from the glass in windows or from spaces directly.
> Frames need to be acoustically isolated and thermally
> broken. Wood frames are much better for this purpose.
>
> One of the shortcomings of relatively new use of cold-formed
> metal studs for exterior walls is that they transmit sound
> and temperature far more than masonry, so much so that
> green designers recommend that they not be used despite
> seeming cost savings.
>
> Metal studs in gypsum board walls are wonderful transmitters,
> indeed, the studs and gyp board may act as amplifiers, no
> matter the STC rating derived from other characteristics.
> Again, wood studs are preferrable, or the metal studs must
> be isolated by double layering and gasketing.
>
> Wet wood is a transmitter of signal and temperature, dry
> wood less so.
>
> There are synthetics and/or composities which can take the
> place of wood and metal studs. Not yet cheap enough to be
> used widely.
>
> Now, metal nails, screws, brackets, masonry reinforcement,
> ties, support angles and whatnot still remain a source of
> signal. High-strength adhesives and isolation devices
> improve the resistance to transmittal.
>
> The wondrous materials of the stealth machines may come
> into architecture some day, but not soon. Well, maybe the
> TLAs are using them in SCIFs, the super-versions.
>
> Bamford's latest book is chock full of nightmare technology
> and programs for invasive methods well beyond most of
> healthy paranoia about incomsec.

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