Definition of N10-value
The N 10 value is a comparative value that applies to acoustic products with sound absorbing properties.
With the N 10 value, a quick indication can be given of how many of a specific product are required to reach a sound absorption area of 10 m2 Sabine. The N 10 value is calculated from the sound absorption spectrum of the object to give a speech relevant sound absorption value.
Technically, the N 10 value is calculated from a specific product's sound absorption area at the dimensioning speech relevant octave band by formula (1), where A dim is calculated from the mean value of the product's sound absortion area in the 1/3 octave bands 400 Hz , 500 Hz and 630 Hz (belonging to the octave band 500 Hz) according to formula (2). If the sound absorption surface is lower in one of the octave bands 1, 2 or 4 kHz, the corresponding mean value for the 1/3 octave bands (included in the octave band), is used in the N 10 evaluation.
The number of decimals used in the calculation depends on how large the maximum sound absorption area is for all 1/3 octave bands. A dim is calculated with 2 decimals if the maximum absorption area is between 1 m2 and 10 m2. If the maximum sound absorption area is greater than 10 m2, 1 decimal is used. If the maximum sound absortion area is less than 1 m2, 3 decimals are used, and if it is less than 0.1 m2, 4 decimals are used.
The N 10 value is given with one decimal for N 10 < 10 and without decimals for N 10 ≥ 10.
For example, 80 pieces of a product with a N 10 value of 80, are needed to provide 10 m2 Sabine speech relevant sound absorption area, while a product with a N 10 value of 1 would only need a single one of the product. This simplifies the comparison between different sound absorbing products and helps sales representatives communicate how much sound absorption is achieved by different products.
A lower N 10 value means that the product absorbs speech more effectively, but that does not necessarily make it better in all situations. The primary purpose of N 10 is to facilitate comparisons between products of similar size, thus making price indications easier for practical installation.
