Walls; Windows - Polycom HDX series Reference Manual

Walls

Windows

with people at the far-end of any connection. In short, we must always ask
ourselves, "What does this look like and sound like to the people at the
farend?"
In order to guarantee that the final conference environment will have a solid
foundation, we begin with the construction of the walls, floors and ceilings for
videoconference spaces.
Conference room walls should be built from slab to slab. That is, there should
be no gaps from the concrete of one floor to the concrete of the next floor.
Resilient, gypsum board mountings should be used to close any gaps. The
thickness of the gypsum board should be 5/8" or more (one layer of 5/8" and
one layer of 1/2" bonded together would be ideal) on the inside of the room,
with 1/2" thick (or as required by local building codes) appropriate for the
outside of the walls. There should always be a difference in thickness between
the materials used on the inner versus the outer walls. That difference in
thickness subdues mechanical coupling (vibration) between the two layers. A
good overall wall thickness is 6". It is recommended that "offset stud"
construction be used, typically a 6" header and footer with 3.5" verticals
attached in an alternating pattern one toward the outside of the footer, the next
toward the inside and so on.
Fiberglass dense batting or mineral rock wool, 4" to 6" thick (the equivalent of
R-11 to R-13) should be placed in the wall space. The thickness of the batting
is not critical. The critical aspect is that it must be loosely placed in the wall
space, not compacted to fit. The resultant wall will have excellent acoustic
isolation from the outside world. More significant acoustic isolation can be
achieved by placing an additional barrier layer within the wall space.
Typically this barrier will be made of a dense polymer material, about 1/8"
thick, and the improvement regarding loss of sound transmitted through the
wall will be roughly a factor of 10. These materials are available from a variety
of manufacturers.
Windows usually present the equivalent of an acoustic nightmare (as well as
altering the way a camera renders colors and brightness). They not only
transmit room sound, but also allow unwanted outside noise to intrude on the
conference space. In the event that windows cannot be avoided, it becomes
essential that window treatment of some sort be used. This treatment should
match the interior look and feel of the space, while providing a high level of
sound and light block. Typically a heavyweight drape (24 ounces or more) of
heavy fullness (not less than 6" fullness on not less than 8" centers per fold) is
preferred. In all cases, the use of sheer draperies or standard vertical or
horizontal blinds should be avoided, due to their inherent inefficiency in
blocking sound and light, and the fine lines they create within the camera field
of view.
Room Design and Layout
A - 3