Acoustic ratings

STC and NRC: about acoustic panel ratings

Few days ago Acoustic Panels Art visitor asked our experts to clarify specific ratings: NRC and STC. What they really mean and how acoustic panels are rated. First of all, let us explain what are NRC and STC.

Noise Reduction Coefficient or NRC rating

NRC rating by Acoustic Labs
Acoustic Panels have excellent NRC ratings: 0.91 (min) and up to 0.98 (soundproofing panels with imprint).

Noise Reduction Coefficient or NRC rating is most commonly used to rate general acoustical properties of acoustic ceiling tiles, baffles, banners, office screens, and acoustic wall panels. It is occasionally used to rate floor coverings.

An NRC of 0.0 indicates the object does not attenuate mid-frequency sounds, but rather reflects sound energy. This is more conceptual than physically achievable: even very thick concrete walls will attenuate sound and may have an NRC of 0.05. Conversely, an NRC of 1.0 indicates that the material provides an acoustic surface area (in units sabin) that is equivalent to its physical, two-dimensional surface area. This rating is common of thicker, porous sound absorptive materials such as 2″-thick fabric-wrapped fiberglass panel. Materials can achieve NRC values greater than 1.00.

The noise reduction coefficient is the arithmetic average, rounded to the nearest multiple of 0.05, of the absorption coefficients for a specific material and mounting condition determined at the octave band center frequencies of 250, 500, 1000 and 2000 Hz.

Our sound absorbing acoustic panels with or without prints are rated NRC 0.91 or 91% noise reduction.

If you look for best possible noise reduction, you should check our soundproofing acoustic panels. These have NRC 0.98 (98% noise reduction). These panels absorb indoor and block outdoor noises!

Sound Transmission Class or STC rating

Sound Transmission Reports by Acoustic Labs
Sound Transmission Reports (STC rating) by Acoustic Labs

Sound Transmission Class or STC is an integer rating of how well a building partition attenuates airborne sound. In the US, it is widely used to rate interior partitions, ceilings, floors, doors, windows and exterior wall configurations. The higher the value, the better a structure is at reducing airborne sound. For example, STC rating of 60 indicates good soundproofing – most sounds will not disturb neighboring residents.

Our soundproofing acoustic panels are rated STC 31.

Acoustic Lab Test Results: NRC and STC

You can find then download complete lab tests results here (NRC) and here (STC).

Our online chat is available 7 days a week. Please feel free to ask any questions about noise reduction, sound absorption ratings, soundproofing and acoustic solutions for home, office, church or professional recording studio. We’ll be happy to assist you!