How We Test Sound Absorbers
Sound Absorption and Soundproofing: What's the Difference
Sound is like water. It doesn't have a shape or form, but molds itself to its surroundings. And like water, sound can be absorbed by some materials and contained by others. Click here to learn more sound basics.
Soundproofing products trap the sound. They contain the sound within a space, making it impossible for the sound to move to other parts of the building. They also stop unwanted sound from entering the room. Click here to learn more soundproofing basics.
Sound absorption products, on the other hand, soak up sound. They absorb sound waves and prevent them from bouncing off the walls. They improve the quality of the sound within a room. Click here to learn more sound absorption basics.
What's NRC?
To be able to compare the performance of different sound absorption products, we rate them by how much sound they can soak up. This rating is called NRC, which stands for Noise Reduction Coefficient.
Generally, the higher the NRC rating, the better the product is at absorbing sounds.
How is NRC determined?
The NRC rating is determined by testing the sound absorption material using a speaker and a microphone.
A fully enclosed room is set up with a speaker on one end and a microphone on the other. The speaker emits a specific sound at 250 Hertz, 500 Hertz, 1000 Hertz, and 2000 Hertz. These frequencies (pitches) represent the range of the human voice.
The microphone captures readings used to determine the level of sound in the room without a sound absorption product, like Echo Absorber™ Acoustic Panel.
After the baseline readings are gathered, the Echo Absorber™ Acoustic Panel is placed on the floor between the speaker and the microphone. The sound level is measured again.
At 250Hz the Echo Absorber™ Acoustic Panel reduced the amount of sound in the room by 22%. It receives a score of .22 at 250Hz.
Once all frequencies have been tested, they are averaged and rounded to the nearest .05. Here are the measurements for the Echo Absorber™ Acoustic Panel:
| Frequency | 250Hz | 500Hz | 1000Hz | 2000Hz | Total |
|---|---|---|---|---|---|
| Reduction | .22 | .62 | .85 | .90 | 2.59 / 4 = .65 |
Echo Absorber™ Acoustic Panel has an NRC (noise reduction coefficient) of .65. Meaning, on average, it absorbs about 65% of the sound it encounters.
Low frequency sounds are created by home theaters, recording studios, and gun ranges. If you have a low frequency application, call us at 1-866-949-9COW to find the right product.
NRC Depends on the Install
It's important to note the NRC rating is based on testing a product that has been installed in a specific way. To achieve the same results, your product needs to have been installed using the same construction method. If your product has not been installed properly, it will not be as effective (have as high of an NRC rating).
Before you purchase any sound absorption product, be sure to check the NRC reports to determine if your construction method will achieve the results you want.