NOISE AND STRATEGIES FOR NOISE REDUCTION

reflected, transmitted, absorbed

How Sound Behaves within a Space

NOISE REDUCTION

refers to the perceived

difference in sound levels between two

enclosed spaces.

SOUND ABSORPTION

In a normally constructed room without

acoustical treatment, sound waves

strike the wall, ceiling, and floor surfaces,

which then transmit a small portion of the

sound to adjacent spaces. The surfaces

absorb another small amount of the

sound, but most of it is reflected back

into the room.

carpet

is the only floor finish that absorbs

sound.

Transmission loss

is a measure of

the performance of a building material

or construction assembly in

preventing the transmission of

airborne sound.

mass, separation into layers, absorption

Three factors enhance the TL rating of a

construction assembly:

mass

In general, the heavier and more

dense a body, the greater is its resistance to

sound transmission.

Separation into layers

Introducing air

spaces into the construction assembly disrupts

the path through which sound may be

transmitted from one space to another.

Absorption

Absorptive materials help to

dissipate sound in a room.

sound transmission class (STC) rating

is a single number that provides an

estimate of the performance of a partition in certain common sound insulation

situations.

white noise

is

sometimes deliberately introduced into a

space to mask or obliterate unwanted

sound.