Acoustic solutions adapted for sound comfort.


Acoustic solutions tailored to sound comfort.


You help to better understand the constraints related to acoustics and support you in choosing an acoustic solution adapted to your daily uses, for a global approach to sound comfort.

How can we offer the best possible acoustic textile solution?

  • Thanks to the understanding of the acoustic behaviour of our different fabrics (refer to pdf acoustic tests)
  • Thanks to a knowledge of the acoustic mechanisms in our expertise, the curtain: watch the tutorial.
  • Experiences on real cases.
  • Close partnerships with customers  experts in acoustic

The fabric like any other material, has specific acoustic behaviours which will vary in accordance to its implementation and to its surroundings.

So it is important to select its fabric, not only by itself but also by taking into account the different constraints of its surroundings, of its users and of course the acoustic comfort that we expect to reach.

For instance, a classroom will not be acoustically treated in the same way as a theater, a cinema room or a brewery restaurant.

It is so relevant not to select the fabric only on the basis of its alpha w or NRC coefficient.

These coefficients are an average of several acoustic absorption results measured on a large frequency band (from the lowest audible sounds to the highest ones). All of these measured in a normalized configuration which is consequently ,most of the time, different from the real case.

So an acoustic solution has to be defined on the basis of precise specifications for which Sotexpro can support you by offering a pesronnalized following through its experts network.

Real cases done with a partner

Definition of the absorption coefficient

Acoustic performance is assessed using two coefficients, αw and NRC, which measure a material’s sound-absorbing ability. In both cases, they are measured on a scale from 0 to 1, where 0 refers to no absorption and 1 means total absorption.


  • The αw coefficient is calculated in accordance with the ISO 11654 standard, and corresponds to the average alpha coefficients measured by frequency across the One-Third Octave band.
  • The NRC, or noise reduction coefficient, is the average absorption coefficient measured at four frequencies (250, 500, 1000 and 2000 Hz) in accordance with the ASTM C423 standard.

Product absorption classes :

The acoustic absorption class is determined based on the value of the αw coefficient.
There are five absorption categories for products, ranging from A to E:

In concrete terms

  • If the absorption coefficient is equal to 0, then the material does not absorb any noise, instead reflecting it in its entirety (resulting in resonance and discomfort).
  • If the absorption coefficient is equal to 1, then the material absorbs all of the noise, resulting in improved acoustic comfort.

In short: the closer the coefficient is to 1, the more absorbent the material.

Absorption classes Absorption coefficient
A 0.90 / 0.95 / 1
B 0.80 / 0.85
C 0.60 / 0.65 / 0.70/ 0.75
D 0.30 / 0.35 / 0.40/ 0.45 / 0.50 / 0.55
E 0.15 / 0.20 / 0.25
Unclassified 0.00 / 0.05 / 0.10

Do you have a project?

Our sales staff can provide you with support and in-depth expertise on standards for specific types of establishment (schools, hotels, retirement homes, healthcare, etc.).

Technical features of our fabrics