When STC and SRC reveal how well noise passes by various supplies, NRC (Noise Reduction Coefficient) actions how properly supplies quit sound from reflecting (just how much sound they can absorb). The NRC is The proportion of sound that a surface absorbs (To paraphrase, hits a floor and doesn't reflect https://energyefficiency06813.blogdun.com/32567737/how-much-you-need-to-expect-you-ll-pay-for-a-good-noise-pollution