To prepare soldiers for the cacophony of battle, researchers at Missouri University of Science and Technology have created an “immersive audio environment” for military combat training. The facility — which can produce sounds including tanks, gunfire and helicopters — is meant to help soldiers ready for combat zones.
Why is it necessary to build an audio environment for solider training?
It’s an idea for habituation of the troops for a different environment. We’re near Fort Leonard Wood, which does training for soldiers at all levels. They train a war fighter from private to colonel. They have officer training programs. We thought it would be interesting and useful for them to train in a situation where they would be using their skills — and that would be in a battle-type environment. The idea is to simulate that much in the way NASA has simulators for astronauts. If you ever read The Right Stuff, you’ll remember that some of the astronauts were actually a little bit bored when they went up in the Saturn V. I don’t think people would be bored in battle, but that’s the idea.
What does the facility look like and what equipment do you use to create battle sounds?
It’s 36 feet long, 18 feet wide and 15 feet high. It’s in a cathedral shape with a dome top. It’s basically a truss structure and hanging off the truss are 64 loudspeakers. We have four subwoofers at the bottom that go down to 20 hertz and they provide the Earth-shaking and help us with the sound of explosions going off. We have 12 large speakers that circle at about head height. Then we have satellites, which are loudspeakers 200 hertz and above. They hang in the truss in the ceiling. They go all the way down to the floor, too. You’re completely surrounded by loudspeakers.
How loud does it get inside?
We can do some serious damage if we’re not careful. If everything is going in the whole structure, we can get to 130 [decibels]. That’s quite a bit louder than a rock concert. We have to be very careful. We have to have a loudness profile to make sure that when we put test subjects in we don’t damage their hearing.
So you’re still in the test phase?
We’re finishing building it now. The next phase is to do validation testing. The plan is to use university student volunteers to do testing.
How do you envision the facility eventually being used by the military?
We’re still at the early stages, so we don’t know exactly. For instance, at Fort Leonard Wood there are leadership training courses where the soldiers are performing various tasks. We would envision them actually performing those normal tasks that they would be training for, but they would be immersed in the audio of a battle scene.
There are 3-D immersive environments that you can get, for instance, from gaming engines. You wear a headset. This time in the immersive audio environment, you don’t have to wear a headset. You can wear your normal gear. It’s made for unit-level training. We envision five to 10 people to be able to be inside the environment at a single time. They can interact as they normally would without having any special equipment, which is important because a lot of times when soldiers wear helmets that changes their perception of sound in their environment.
Are there other facilities like yours around the country?
There are, but this is designed to be portable. There is a facility at the Aberdeen Proving Ground in Maryland. The Army Research Lab has one. This is the Human Research and Engineering Directorate’s EAR facility — environment for auditory research.
Why is this work important to you? Do you have a military background?
My background is all civilian. I used to work at Bell Laboratories for many years in acoustics research. I’m interested in audio and what can be done with loudspeakers and microphones and the mathematics that go with that. My background is in adaptive filtering, speakerphones.
How did you come to do this project?
It was in conjunction with Bill Chapin of AuSIM in California. He built an environment like this for auditory research. He had written software and put together equipment for their facility. The facility is quite impressive. It’s got four or five research spaces for sound and over 450 loudspeakers to do various tasks. But their emphasis is for research and not for training. One of the important aspects of the [our facility] is we can take it down and put it up relatively quickly — in a day or so.
Is your vision that it will be transported to where it’s needed?
It could be taken from one Army training center to another, sort of like how you would move a band with all of its loudspeakers and instruments. Our truss structure can be taken apart and put back together in other places. All of the equipment is built for travel.
Image: Steven Grant