The study of sound generation and noise has become extremely important in recent years as the general public has become increasingly sound conscious. Coupled with increasing legislative pressure for quieter, more efficient vehicles, the need for automotive manufacturers to make adjustments to the acoustics of their products is higher than ever.
In acoustics analysis, a free-field measurement room offers an economic and, more importantly, space-saving solution. These facilities provide an environment free of structurally transmitted noise and vibration. There are typically two types of free- field room design that are used. Absorption is usually either in the form of anechoic wedges or a flat panel system. In either case, the absorptive material used is tuned to match or improve the desired cut-off frequency of the chamber. Anechoic wedges maximize the surface area, which provides very high performance over a wide frequency range; flat panels can be finely tuned for certain frequencies, including low-frequency applications.
The Moduline acoustic construction panel system available from IAC has been specially developed for acoustic testing facilities and is suitable for use with either flat absorption panels or anechoic wedges. The most important factor to consider when designing a free-field anechoic facility is the relationship between the volume of space in the room and the size of the test subject. Typically, the larger the room, the higher the absorption required in order to maintain a usable free-field measurement area. In addition to high-quality sound absorption, correctly specified measurement locations are essential at the design stage to ensure the accuracy of maximum allowable differences between the measured and theoretical levels set, according to the ISO 3745 standard. IAC Acoustics has 70 years’ experience in the design, manufacture and installation of both styles of facility and can provide technical advice on the best choice for individual requirements.