acoustics
PROJECT
Addressing Noise Issues Poor acoustics in existing spaces have a variety of solutions. Baffles provide double-sided absorption, but with a smaller overall system depth than clouds.
A
well-informed architect or interior designer
source has stopped emitting a sound. It is expressed in
Acoustically absorbent materials, such as high-density
involved in new construction has an infinite
seconds. RT can be calculated mathematically based on
fiberglass clouds, baffles, and direct-to-deck ceiling and
variety of products available to create an
the volume of the room and the square footage of sound-
wall panels are extremely effective at reducing reverbera-
acoustically optimized space from the ground up. Un-
absorbing surfaces within it, or it can be measured with a
tion time.
fortunately, not every new space is built according to
sound-level meter.
When speech privacy is a specific concern, such as in
acoustically enlightened principles, leaving thousands
Background noise is the noise level in a space mea-
an open-office setting, acoustic masking can be added
of offices, classrooms, restaurants, and other spaces with
sured when the specific noise being studied is absent. Ma-
alongside absorbent installations. This involves introduc-
poor acoustics and sound control, giving occupants and
jor sources of background noise are HVAC noises, out-
ing finely tuned volume and frequency signatures that fall
owners a headache.
door noises, reflected speech sounds (echo), and noise
within the acoustical range of human speech. It doesn’t
It can be difficult to fundamentally change the way a
from adjacent spaces. Background noise is usually ex-
eliminate speech sounds, but rather it reduces the physical
built space behaves acoustically. HVAC systems aren’t eas-
pressed as dBA, a measure that reflects the response of the
zone of speech intelligibility by blending in with them.
ily replaced or rerouted. Trendy finish materials won’t be
human ear, which is less sensitive to low and high
abandoned, even if they turn a café into an echo chamber.
frequencies.
The addition of a wall-to-wall suspended ceiling is rarely
Calculating the precise amount of sound absorption in a space using the sound-absorption coefficient for each material multiplied by the surface area of that material,
practical. However, there are steps that can be taken to
REVERBERATION VS. ABSORPTION
then finding the sum of all absorptive materials in the
address noise issues in existing spaces with limited disrup-
Sound reflects readily off of hard surfaces, as relatively
space, is more math than anyone but professional acousti-
tion to the occupants and the operating budget.
little energy carried in the sound wave is absorbed into
cians care to do on the subject. Fortunately, there are
A number of tests can be performed to determine
the surface material. As reflection builds throughout a
some general rules of thumb that can be followed to deter-
whether a space meets the requirements of acoustic com-
room, a web of competing sound waves gradually decays
mine how much sound absorption is needed in a given
fort. These can be performed by professional acousticians,
as it is absorbed, bit by bit, into the exposed surfaces in
space, based on the form the acoustic material takes. Each
but technical support teams for acoustic ceiling and wall
the space.
form has its advantages, depending on the design con-
Reverberation is an increasing problem due in part to
manufacturers also have the appropriate expertise and
some current interior-design trends. Hard-surface floors,
equipment to test a facility. The two most practical measurements are reverberation time and background noise. Reverberation time (RT) is time required for an average sound in a room to decrease by 60 decibels, once the 36
COMMERCI A L A RCHI T EC T URE
JUNE 2018
cerns and structural realities of the space requiring remediation.
the move away from fabric-covered cubicles, glass walls and partitions, open plenums, and exposed structures all
DIRECT-TO-DECK PANELS
add to the reflective surfaces, increasing reverberation
Direct-to-deck acoustic panels, which can be glued or
times.
screwed directly to the ceiling structure without wires or
commercialarchitecturemagazine.com
