During the last 10 years, different techniques have been developed to measure the material parameters of poro-elastic materials. Measuring tortuosity and characteristic lengths using the ultrasonic technique have become a procedure that is available in several laboratories now. Until recently, data of the elastic properties of poro-elastic materials were obtained using quasi-static techniques that only provide data at low frequencies. Since a lot of damping and sound absorbing materials are visco-elastic, the elastic coefficients may depend strongly on frequency and temperature. In this talk, we will give an overview of the different techniques available for the characterisation of sound absorbing materials.