Remarkable New Sound Research Facility added at Boys Town National Research Hospital
Monday, January 20, 2020
The first thing you notice when entering the new anechoic chamber at Boys Town National Research Hospital is how big the chamber is. The large white cube stands over 18 feet high and occupies roughly 400 square feet of floor space. The anechoic chamber is the newest addition to our sound research facilities and is also the most advanced facility of its kind in the region.
The chamber is isolated from outside noise and vibrations by thick walls and sound-deadening insulation. The walls, floor, and ceiling inside the chamber are also completely covered by triangular shaped structures called anechoic wedges that are 19 inches tall. The shape, size and arrangement of the wedges are designed to control all but the lowest frequency sound reflections inside the booth. (Figure 1). Finally, a floating, mesh floor suspends occupants above the same wedges in the floor of the structure. These features make the inside of the chamber very quiet with virtually none of the reflected environmental sounds that we hear without thinking about every day. It’s an interesting location to talk to G. Christopher (Chris) Stecker, PhD, the director of the Spatial Hearing Lab, about the new facility.
Inside, the chamber is configured with a 96-channel speaker system to enable a range of sound simulations and experiments. Dr. Stecker explains that “the array is used for research on hearing and localization of sounds in 3-dimensional spaces. For example, the system can simulate classroom sound environments that helps researchers understand how children develop the ability to focus on one person who is speaking without being confused or distracted by other speakers or noises. This research is relevant for things like refining hearing aid and cochlear implant technology so that they convey the best possible spatial and voice information. Interestingly, the same equipment can also be used to demonstrate for others how a noisy world sounds through a hearing aid or cochlear implant."
Figure 1.
Anechoic wedges, 19 inches measured from base to apex of the triangle, cover the walls floor and ceiling to eliminate all but the lowest frequency sound reflections inside the chamber.
In another type of experiment, tiny microphones can be placed on the ear to measure the influence of head position and ear anatomy on our perception of sound location with assistance from the large speaker array. One use of this capability according to Dr. Stecker is testing by companies developing virtual reality applications. “In order to create convincing virtual environments, it is necessary to know how sound coming from different locations is affected by the ear anatomy so sound cues can be simulated by headphones placed physically on the ear.”
The described experiments are only some examples of what is possible in the anechoic chamber. We expect that other labs and other research institutions will want to answer a wide range of sound related questions in this space. Support services for the anechoic chamber will also be available through our technology core services. Those interested in conducting research using the anechoic chamber can contact Dr. Chris Stecker in the Spatial Hearing Lab at Boys Town Hospital.
We are grateful to the National Institutes of Health (NIH), and the Great Plains Institutional Development Award for Clinical and Translational Research (IDeA-CTR) for the financial support that helped make the chamber a reality. The Great Plains IDeA-CTR is an NIH-funded program to increase training, collaboration, development of core facilities, and resources for clinical and translational research at in our region.
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