Infrasound is the low frequency rumble created by large, intense noise sources such as aircraft engines, wind tunnels and industrial processing systems. It is often felt more than heard causing an uncomfortable feeling in the chest. We use a variety of techniques to diagnose and treat infrasound problems in test facilities:

• subscale model tests to evaluate the effect of different flow control devices
• site surveys
• analytical calculations

Site Surveys: Field measurements show a wide variation in noise level. Measurements at individual sites vary by a considerable amount even after the data is scaled to a common reference engine size and measurement distance. This is due to the quality of the acoustic design and the location of adjacent buildings.

Analytical calculations evaluate the effect of buildings adjacent to a low frequency noise source