We bring acoustic properties to your products by designing the microscopic morphology of your materials or by applying innovative concepts like multi-scale, property gradients...

Our Consulting, Research or Education services can be applied to various fields of industries like Buillding, Transport and Material manufacturing.

Consulting

• design of end user system for sound and vibration control,
• numerical prediction of material/system performance,
• dedicated software for vibro-acoustic prediction,
• laboratory measurements,
• in situ diagnosis.

You may have an overview of our technical know-how by visiting APMR, "the Acoustical Porous Material Recipes on the web".

Research

We develop models and set-ups to increase our knowledge of newly manufactured acoustical porous materials. Themes we are currently working on include

• a model for acoustical composite materials
• a model for closed-cell materials
• acoustic, elastic and damping characterization methods
• computational techniques to predict the behavior of porous materials in air flows.

Most of our reseach works are available in peer-reviewed scientific journals. Check our references for details.

Education

We provide specific and on-demand educational programs related to our fields of competences:

• sound absorption or insulation measurements and predictions,
• measurement techniques for the acoustical or elastical characterization of porous media.

 

Facilities

Matelys - Acoustique & Vibrations and ENTPE together develop and use facilities for their research and development studies. Facilities comprise test rooms, standing wave tubes and various transducers.

 

Rooms

Matelys - AcV has access to 3 rooms for sound absorption or transmission measurements. Two of these rooms are reverberant. They can be coupled together for transmission loss measurements. The last room is a semi-anechoic chamber, which can be coupled with one of the two reveberant rooms for insertion loss measurements.
These rooms are too small for certification tests. They are used for development tests only.

	Reverberant rooms First reverberant room (3.50 x 7.00 x 2.50 cubic meters). Left picture: a double glass window is under transmission loss measurements.
	Semi-anechoic room Semi-anechoic room (2.00 x 3.65 x 2.00 cubic meters). Left picture: an automotive component is under insertion loss measurements.

 

Standing wave tubes

Five standing wave tubes (also known as impedance or Kundt tubes) are available depending on the material and on the frequency range of interest:

Tube	section/diameter	Frequency range
ENTPE large tube	600 x 600 mm2	50 - 500
Bruel & Kjaer large tube	100 mm	50 - 1 600
ENTPE medium tube	46 mm	100 - 4 200
ENTPE small tube	29 mm	100 - 6 800
Bruel & Kjaer small tube	29 mm	500 - 6 400

 

	ENTPE Large tube Design and manufacturing: ENTPE. Concrete Kundt tube with a square cross section of 600 mm x 600 mm. Length of the tube: 5.5 m. This tube is used for sound absorption measurements of large samples like absorbing wedges of anechoic rooms, ceiling perforated panels...
	ENTPE small and medium tubes Design and manufacturing: ENTPE. These tubes allow estimation of the dynamic density and bulk modulus of acoustic materials with only three acoustic pressure measurements.
	Bruel & Kjaer tubes Design and manufacturing: Bruel & Kjaer. Tube 4106T with a transmission loss kit.

 

Transducers

Matelys-AcV also disposes of a set of complete transducer to realize specific experimental studies in the fields of acoustics and vibrations:

• loudspeakers
• microphones (1/4 inch, 1/2 inch)
• electrodynamic shakers
• accelerometers
• impedance heads
• a laser vibrometer

 

Left picture: example of a modified Oberst beam experimental set-up for the elastic characterization of porous media. For this set-up, the laser vibrometer, a dynamic shaker and a impedance head are used.