How do you choose a high-quality acoustic product?
It is difficult to assess the quality of an acoustic product without the proper criteria. In this article, we present the six indicators used to evaluate the quality of an acoustic product: the NRC value, the Alpha W coefficient, the sound absorption class, acoustic curves, DL_alpha, and measurement conditions.
Acoustic Test Report
To ensure the quality of an acoustic product, it is important to refer to its technical specifications, which must comply with industry standards, and to the test results conducted by a professional organization. It is advisable to request the acoustic test report to verify the product’s quality.
The noise reduction coefficient
The NRC value is a noise reduction coefficient ranging from 0 to 1, calculated in accordance with ASTM C423. It is not very reliable because it only takes into account the average across four specific frequencies (250, 500, 1000, and 2000 Hz). The graph shows that two products can have the same NRC value while exhibiting very different acoustic performance.
The average sound absorption coefficient (SAA) is a more accurate indicator than the NRC value, as it takes into account 12 specific frequencies. It is also calculated in accordance with ASTM C423.
The Alpha W (αw) coefficient measures a surface’s ability to absorb sound wave energy. It is calculated in accordance with ISO 11654 and ranges from 0 to 1. Like the NRC value, it is not very precise because it only takes into account the average of the alphas measured by frequency across the entire third-octave band.
The sound absorption class is determined in accordance with ISO 11654 and ranges from A to E. It uses letters and provides only a general indication of the product’s performance. Below an alpha coefficient of 0.10, the product is not even classified.
It is important to note that these criteria do not provide insight into the product’s actual effectiveness for a given need. However, they are reliable indicators for assessing the quality of an acoustic product.
The average sound absorption
We recommend choosing an acoustic product that comes with a standardized technical data sheet and has been tested by a professional organization to ensure high acoustic quality.
