Acoustic Material Testing

With growing focus on noise control issues, the effect of materials in construction and as insulation makes a huge difference to the acoustic experience – the use of special materials can, for example, transform a space, keep vehicles within legal exterior noise limits, or create a noise-free environment. Acoustic material testing is the process for determining the acoustic characteristics of materials in terms of absorption, reflection, impedance, admittance and transmission loss, and is becoming increasingly relevant to engineers, designers and manufacturers from a broad range of industries. 

The effect of materials in construction and as insulation makes a huge difference in the acoustic experience. In offices and classrooms, the use of special materials can transform a space and with it the activities inside. In some applications – such as aircraft engines – they are what keep the vehicle within legal exterior noise limits. In others, like wind tunnels and anechoic chambers, acoustic materials are essential components in creating a noise-free, uniform test environment.

Creating an acoustic environment

To create a specific acoustic environment, it is necessary to understand the acoustic performance of the materials used. Testing materials for their acoustic characteristics lets architects, designers and engineers understand the contributions they can make to the overall sound, in terms of absorption, reflection, impedance, admittance; including transmission loss. Repeatability and precision are the keys to effective material testing – and data must be exportable to update predictive models.

Mitigating unwanted sound

To remove unwanted noise, one needs to match an acoustic material to the specific characteristics of the sound. But selecting the right material for the job is challenging. Certain materials alter some sound components, such as high frequencies, more than others do. Also, the selected material must create the desired acoustic effect in concert with other materials in the structure. What’s more, the structure’s final shape can affect the acoustic performance of its materials, such as the nacelle liners in an aircraft engine. A precise understanding of the material’s acoustic characteristics, such as its performance at certain frequencies, is essential – both before and after structural integration.