NRC in acoustics stands for Noise Reduction Coefficient and most accurately describes

• A. The color of sound-absorbing materials.
• B. The maximum sound transmission through a barrier.
• C. The durability of a material.
• D. The absorptive performance of a material at mid to high frequencies.

Answer: (D)

NRC, or Noise Reduction Coefficient, measures how much sound energy a material absorbs rather than reflects, averaged over mid-to-high frequencies. It’s calculated from absorption coefficients at four standard frequencies and results in a value between 0 and 1, making it a practical gauge of how well interior finishes work to damp noise in typical speech and noise environments. This focuses on absorptive performance at those mid-to-high frequencies, not on the material’s color, nor on how much sound passes through a barrier (that’s a different metric like STC or Transmission Loss), and it doesn’t describe durability. So the best description is the absorptive performance of a material at mid to high frequencies.