ABOX: Anechoic Boxes

Wireless sensor networks equipped with microphones are low-cost solutions for real-time data acquisition, offering numerous applications such as environmental monitoring, surveillance, bioacoustics, among others. Usually software and hardware implementation are used to evaluate their configuration behavior, followed by in-situ tests. This study proposes a new validation-step using anechoic boxes, allowing emulation in laboratory environment to obtain first impressions, reducing costs and optimizing labor.

The concept involves creating an electro-acoustic chain, where the information to be processed passes through an open-field environment. Two different solutions are presented: the first, made using modular pieces making it easier to build; the second and improved model, applying room acoustics theory. Both boxes were built using materials and components that can be easily found. Using the correct theory and tools, we achieved the fabrication of a portable anechoic environment for emulating wide frequency range soundscapes. Although objectives were achieved, there are future possibilities of improvements, e.g. developing a fast-reliable adaptation system for the entire electro-acoustic chain. Also, there's the opportunity of a study of the polar response of measuring points, allowing the usage of microphone array nodes. Small anechoic volumes also provide opportunities for the development of methods to characterize anechoic environments.