How Does Noise Control Differ from Sound Absorption?
So the noise control discussed above concerns keeping our spaces free from the noise pollution of surrounding spaces. The other important topic in acoustics involves clearly hearing the sound you’re supposed to hear in a space. An auditorium, or even a large meeting room, should allow everyone in the room to clearly hear the speaker’s voice. Rooms that are too reverberant, that echo too much, distort the speaker’s voice and make the speech difficult to understand. Walls, ceilings and floors can all absorb sound or reflect sound. Therefore, sound absorption becomes an important measure in construction. The Noise Reduction Coefficient (NRC) act as the standard measure. An NRC of 0 indicates perfect reflect of sound and an NRC of 1 shows perfect absorption of sound. Some common measures for NRC are: • Concrete or painted masonry = .05 • Carpet = .25 • Heavy carpet on pad = .50 • Suspended acoustical ceilings = .50 to .75 • Fiberglass board 2″ thick = 1.00 Some other NRC values for buildin
