A
sound baffle is a construction or device which
reduces the strength (level) of
airborne
sound. Sound baffles are a fundamental tool of
noise mitigation, the practice of
minimizing
noise pollution or
reverberation. An important type of
sound baffle is the
noise barrier
constructed along
highways to reduce sound
levels at properties in the vicinity. Sound baffles are also
applied to walls and ceilings in building interiors to
absorb sound energy and thus lessen
reverberation.
Highway noise barriers
The technology for accurate prediction of the effects of noise
barrier design using a
computer model
to analyze
roadway noise has been
available since the early 1970s.
The earliest published scientific design
of a noise barrier may have occurred in Santa Clara
County
, California
in 1970 for a section of the Foothill Expressway in Los Altos,
California
. The county used a computer model to predict
the effects of sound propagation from
roadways, with variables consisting of
vehicle speed, ratio of trucks
to automobiles, road surface type, roadway
geometrics, micro-
meteorology and the design of proposed
soundwalls.
Interior sound baffle design
Since the early 1900s scientists have been aware of the utility of
certain types of interior coatings or baffles to improve the
acoustics of
concert halls,
theaters,
conference
rooms and other spaces where the quality of sound is important.
By the mid 1950s
Bolt, Beranek
and Newman and a few other U.S. research organizations were
developing technology to address the design challenges. This design
field draws on several disciplines including
acoustical science, computer modeling,
architecture and
materials science. Sound baffles are also
used in
speaker cabinets to absorb
energy from the pressure created by the
speakers thus reducing cabinet
resonance.
In 1973, Pearl P.
Randolph, a school
bus driver in Virginia
, won a new
school bus in a national contest held by Wayne Corporation for the suggestion that
sound baffles be installed in the ceiling of school buses. In 1981, they were first
made mandatory by the
state of
California.
Vehicle exhaust sound baffles
Baffles are also found in the exhaust pipes of vehicles,
particularly motorcycles.
See also
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