Absorption materials are used to control
sound within a space. Acoustically absorptive materials are typically rated with
number. Some materials may also be rated with a CAC
number (usually ceiling tiles) and yet others may be rated in Sabines.
panels can be used to control harsh reflections, reduce
reverberation time, or eliminate echo. Absorption panels can also be used
to reduce the propagation of sound in otherwise open areas (i.e., down a long
TREATING THE REVERBERANT SPACE
Controlling a reverberant
sound field with sound absorbing materials is often the most practical method
of noise control for institutional, industrial, exposition and correctional facilities.
Experiments in psycho acoustics and speech intelligibility have shown that long
reverberation times make the understanding of speech difficult or impossible.
Also as the reverberation time is shortened, the background noise level is reduced
as speech intelligibility improves. Improvement in communications has long been
recognized as an important feature for most public, commercial and industrial
spaces. A good acoustical environment in school classrooms and child care centers
is now also recognized as a critical factor in the development of early language
skills in very young children.
In many cases, the use of sound absorbing
panels optimized for sound absorption in the speech frequencies, can provide a
satisfactory reverberation time (T60 = 0.4 seconds for example) while preserving
the necessary signal to noise ratio without the need for amplification.
absorption panels come in many shapes, sizes, and materials. Below are some examples: