The N10 value is a comparison value that is assigned to acoustic solutions with absorptive properties.
With the N10 value, a quick indication can be given on how many of a certain product that are necessary to reach an absorption surface of 10 m2Sabine. The N10 value is calculated from the object’s sound absorption spectrum to give a speech-relevant absorption value.
Technically, the N10 value is calculated from a specific product's absorption surface at 500 Hz through the formula
where A500 is the product's absorption surface in the 500 Hz octave band. If the absorption surface is lower in any of the higher octave bands, that value is used in the N10 evaluation. The N10 value is given with one decimal for N10 < 10 and without decimals for N10 ≥ 10.
For example, a product with a N10 value of 80 needs 80 pieces to give 10 m2S absorption surface, while a product with an N10 value of 1 would only need a single item. This simplifies the comparison between different absorptive products, and helps sellers in the communication of how much sound absorption is achieved by different products.
A lower N10 value means that the product absorbs speech sounds more efficient, but it doesn’t necessarily make it better. The primary aim of the N10 value is to facilitate comparisons between similarly sized products, and thus to make price indications easier for a practical installation.