An NRC value increases, what happens to absorption?

• A. It decreases absorption
• B. It remains unchanged
• C. It is unrelated to absorption
• D. It increases sound absorption

Answer: (D)

An NRC value is a measure of how much sound energy a material absorbs, averaged over the mid-frequency range. As NRC goes up, the fraction of incident sound that the material absorbs increases (up to 1). That means more sound is absorbed and less is reflected back into the room, leading to higher overall absorption and typically lower reverberation. NRC is a broad mid-frequency average, so while it doesn’t capture every frequency perfectly, a higher NRC consistently indicates greater absorption. So increasing NRC directly corresponds to increased sound absorption.