Sound reverberation boards are set in to 5 classes with ‘A’ being the best performace and ‘E’ being the lowest.
In the simplest possible terms, a NRC (or Noise Reduction Coefficient) is the number which rates the effectiveness of a material at absorbing sound.
What Does A Noise Reduction Coefficient Mean?
NRC Ratings can range from 0 indicating a perfectly reflective material to 1 indicating a perfectly absorptive material.
One way to look at NRC ratings is to see them as a percentage of sound that comes in contact with a sound absorption material and are not reflected back into the room.
For example, a Noise Reduction Coefficient of 0.7 would indicate that 70% of sound waves are absorbed by the material.
Technical
In the simplest possible terms, a NRC (or Noise Reduction Coefficient) is the number which rates the effectiveness of a material at absorbing sound.
What Does A Noise Reduction Coefficient Mean?
NRC Ratings can range from 0 indicating a perfectly reflective material to 1 indicating a perfectly absorptive material.
One way to look at NRC ratings is to see them as a percentage of sound that comes in contact with a sound absorption material and are not reflected back into the room.
For example, a Noise Reduction Coefficient of 0.7 would indicate that 70% of sound waves are absorbed by the material.
How is NRC Calculated?
The Noise Reduction Coefficient is calculated by averaging how absorptive a material is at four different frequencies: 250hz, 500hz, 1000hz, and 2000hz.
Because the “official” NRC is an average, two materials with the exact same NRC can perform differently in different applications. Each may work best at a different frequency.
NRC ratings are often confused with STC ratings, which are also commonly referenced in the acoustic treatment industry.
The key difference between NRC and STC is that NRC is used to rate materials that ABSORB sound, while STC is used to rate materials that BLOCK sound.
