Acoustic Testing for the Development and Verification of Acoustic Products
Acoustic testing plays a critical role in the development, verification, and performance evaluation of acoustic products. Accurate acoustic testing ensures that products deliver the required sound absorption, sound insulation, diffusion, and noise control performance for specific architectural and commercial applications.
By measuring key acoustic performance indicators such as sound absorption coefficients, transmission loss, reverberation control, and sound isolation ratings, acoustic engineers can determine how effectively a product improves the acoustic quality of a space. These results help architects, designers, engineers, and project consultants select the correct acoustic treatment solutions for each environment.
Different environments require different acoustic performance characteristics. For example, an open plan office may require highly sound-absorbing acoustic panels to reduce reverberation, control ambient noise, and improve speech intelligibility. In contrast, a theatre or performance venue may require carefully engineered acoustic diffusion and reverberation management to create a richer and more balanced acoustic experience.
Accurate acoustic testing data is essential for architects and acoustic consultants when designing high performance environments. This information assists in predicting sound behaviour within a space and enables the optimisation of room layouts, surface materials, and acoustic treatments to achieve targeted acoustic outcomes.
At Acoustic Worx, years of research, acoustic analysis, and product testing have resulted in the development of a world class range of custom acoustic products engineered specifically for the built environment.
Our acoustic solutions are precision designed to:
Maximise sound absorption performance
Improve absorption bandwidth across key frequencies
Enhance speech intelligibility and acoustic comfort
Reduce unwanted reverberation and noise
Deliver cost-effective acoustic treatment solutions
Meet the demands of modern architectural spaces
Acoustic Worx combines acoustic engineering expertise with innovative product development to provide high performance acoustic panels, ceiling systems, wall treatments, and custom acoustic solutions for commercial, educational, hospitality, religious, and performance environments throughout South Africa and Africa.
SANS Standards for Acoustic Testing
Development & Verification of Acoustic Performance for the Automotive Industry
Acoustic testing plays a vital role in the automotive industry, where manufacturers continually strive to reduce NVH (Noise, Vibration and Harshness) levels in motor vehicles. The acoustic performance of vehicle components directly influences the overall driving experience, vehicle refinement, passenger comfort, and perceived product quality.
Low interior noise levels contribute to a quieter, smoother, and more enjoyable driving environment an important factor in modern vehicle design and consumer purchasing decisions. As automotive manufacturers compete in both local and international markets, vehicle components developed and manufactured in South Africa must meet stringent acoustic performance standards to remain globally competitive.
The rapid development of electric vehicles (EVs) has also shifted the focus of automotive acoustic engineering. While electric vehicles significantly reduce traditional combustion engine noise, other noise sources such as tyre noise, wind noise, road noise, drivetrain noise, and structural vibrations become far more noticeable within the cabin environment.
This evolving acoustic landscape has increased the demand for advanced automotive acoustic materials and precision engineered noise control solutions capable of improving interior comfort while maintaining lightweight and cost effective vehicle design.
At Acoustic Worx, acoustic testing and material development are used to evaluate and optimise the acoustic performance of automotive components and sound control materials for a wide range of NVH applications.
The acoustic behaviour of a material is influenced by several important physical and acoustic properties, including:
Porosity
Tortuosity
Airflow resistivity
Material density
Thickness and weight
Thermal and viscous characteristic lengths
Sound absorption characteristics
Vibration damping properties
Understanding and accurately measuring these parameters allows for the development of high performance acoustic materials engineered to reduce unwanted noise, control vibration, and improve vehicle cabin acoustics.
Acoustic Worx combines acoustic engineering expertise, testing capabilities, and advanced material analysis to support the development and verification of acoustic products for the automotive and transport industries, delivering innovative NVH solutions designed for modern vehicle environments.
Acoustic Testing – Impedance Tube Testing
Absorption Testing in accordance with ISO 10534-2
Transmission and Insertion Loss Testing in accordance with ASTM E2611-17
Impedance Tube Testing is widely used for measuring acoustic performance as a function of frequency in the development stage of product design. The results show normal incidence (sound incident on a surface at 90 degrees). The frequency range of testing is a function of the tube length, tube inner diameter and microphone diaphragm diameter.
Tests are performed at predetermined locations with very accurate distances between microphones and distance to the sample face. A discrete Fourier transform derives the transfer function, the reflection coefficient and the absorption coefficient. In the case of insertion or transmission losses, the number of microphone measurement locations increase and measurements are performed with two different terminations.
Acoustic Worx developed tube sets are precision engineered for accuracy and includes in house software to measure and process the results.
Acoustic Testing – SILT Cabin
Sound Insertion Loss Testing (SILT) is measured based on SAE J1400 (Society of Automotive Engineers).
Acoustic Worx Silt test station is made up of two chambers, one of which is an excitation chamber and the other a receiver chamber. The SILT Cabin determines the accumulated decrease in sound pressure of waveform energy as it passes thru a barrier. Transmission Loss and Insertion loss measurements are used extensively in the motor industry for product developed / design to control noise. This test process can also measure acoustic performance of materials used in buildings such as doors, glazing, window seals, drywalling, ceiling tiles etc.
Acoustic Testing – Alpha Cabin
Random Incidence (all angles) absorption testing is defined in ISO 354 and ASTM C423
An Alpha cabin is a 1:3 scaled version of a full Reverberant Chamber. All walls are angled and additional internal diffusion creates a dense sound field. Parts are measured on the chamber floor in regular “A” mounting or on standoffs for “E” mounting.
Alpha Cabin testing is used extensively by material manufacturers and automotive manufacturers to determine the acoustic absorption performance of materials and moulded parts. Materials often comprise of a number of different layers, solid, elastic, porous, impervious and resistive thin layers with most of the elements varying in thickness. Parts are shaped and have various mechanical and mounting constraints.
Acoustic Worx Alpha Cabin is used extensively for acoustic performance testing and product development.
Acoustic Testing – Air Flow Resistivity Meter
Air Flow Resistance shows, in an indirect way, the structural properties of a material and its ability to perform as an adiabatic absorber. This is useful for 2 purposes:
- In relating the acoustic properties of a material to its structure and method of manufacture
- Quality control to ensure uniform acoustic performance in production.
AFR is a function of air flow pressure differential, sample size and sample thickness.
This type of test apparatus can measure
- Air Flow Resistance in Pa.s/m3
- Specific AirFlow Resistance in Pa.s/m
- Air Flow Resistivity in Pa.s/m2
- Linear Air Flow Velocity in m/s
Understanding these parameters of open-cell porous materials is vital in developing an effective acoustic product for noise, reflection and reverberation control. Acoustic Worx has developed a highly accurate Air Flow Resistivity Meter for product development but also to ensure we maintain the best possible acoustic results for our clients.
