Sound absorbers are soft, porous,
open-celled materials such as foam sheets or
fiberglass blankets and baffles that reduce
the reflection of sound waves. Their sound
absorption efficiency is rated by a "NRC"
number - Noice Reduction Coefficient*. The
HIGHER the NRC rating, the more EFFICIENT
the product is at absorbing noise.
*NRC is a sound absorption rating. It
measures a percentage of how much sound will
not be reflected back from where it came.
Based on a range from .05 to 1.0, where a
NRC of 1.0 means that all the sound energy
that hits that product passes through it and
does not "bounce" back to its source. A NRC
of .60 would reflect 40% of the sound back
to the source and let 60% of the noise pass
Noise Barriers combine mass, flexibility and
limpness to block noise from transmitting
from one area to another. Flexible
mass-loaded vinyl sheeting has replaced thin
lead sheets as the noise barrier of choice.
Noise Barriers are rated by a "STC" number -
Sound Transmission Classification. The
HIGHER the STC rating**, the more EFFICIENT
the product is at blocking noise.
Sound Transmission Class : Single-number
rating of airborne sound insulation of a
partition, derived by fitting a reference
rating curve to the sound transmission loss
values measured for the 16 contiguous 1/3
octave frequency bands with nominal mid-band
frequencies of 125 Hz to 4000 Hz inclusive,
by a standard method. The standard method
typically used is ASTM Standard E90. This
test is valid for single homogenous layers,
multiple layers, or complete assemblies. A
higher STC rating typically represents a
better ability to stop noise, frequency
Acoustical Composites are products that
combine both Noise Barrier & Sound Absorber
materials. Typically, they olffer the most
significant overall noice reduction.
Acoustical Composites are rated in both
"NRC"* and "STC"** numbers. Sound Seal uses
composite materials as Panels, Acoustical
pipe & duct Lagging or in Acoustical Curtain