What NRC Actually Measures
NRC, or Noise Reduction Coefficient, is the average sound absorption across four frequencies (250, 500, 1000, 2000 Hz), expressed from 0 (fully reflective) to 1 (fully absorbed). A PET acoustic panel typically scores 0.75-0.95, meaning it swallows most reflected speech and echoes.
How Panels Are Tested
Labs use ASTM C423 (for absorption) and report the results as NRC. A panel mounted with an air gap scores higher than the same panel flat against a wall. This is why our wood slat panels list tested values with the recommended 12mm gap.
NRC vs SAA
SAA (Sound Absorption Average) is the newer ASTM metric covering 12 frequencies. It is stricter and harder to game. When a supplier only shows NRC, ask for SAA if the project is spec-driven (offices, studios, schools).
Choosing by Room
- Home office: NRC 0.7+ on two opposite walls
- Recording booth: NRC 0.85+ on all surfaces
- Open restaurant: NRC 0.6+ on ceiling + upper walls
Don't Confuse NRC with STC
STC (Sound Transmission Class) measures how much sound passes through a wall - blocking, not absorbing. An NRC 0.9 panel can still let a neighbour hear you if the wall itself is thin. Treat both layers for real privacy.
Need certified values for tender documents? Our 工厂 supplies ASTM-tested reports with every OEM batch.