A classification of assemblies (based on lab testing) in their ...

[Collmarie]

A classification of assemblies (based on lab testing) in their ability to dampen sound in airborne transmission is referred to as:
 
   NRC ratings
   STC ratings
   NC ratings
   All of above

Question 2

Uniform background sound can be achieved by:
 
   Installing a sound masking system (sometimes
  called white noise) into the plenum space of a
  building or room
   Allowing the HVAC system to continually blow air
   Manipulating the placement of materials that can redirect sound waves
   Using an audio system tuned into soft music

[joechoochoy]

Answer to Question 1

STC ratings

Answer to Question 2

Installing a sound masking system
(sometimes called white noise) into the plenum
space of a building or room

[Collmarie]

Thanks

[joechoochoy]

Welcome