Imagine standing in a room where the only sounds are the ones you make. Thereβs no rumble from cars in the distance, no murmurs of conversations from the hallway, no hum from the air conditioner. Even your own voice, footsteps and shifts are sharper, sans the usual reverberations that accompany them. Here, the sounds you make donβt reflect like they would in a normal room.
Welcome to ΒιΆΉΣ³»΄«Γ½βs anechoic chamber.
Located in the ΒιΆΉΣ³»΄«Γ½ Innovative Center, the 217-square-foot chamber is not big by any means β but the impact it will play in understanding and improving hearing certainly is.
βAnechoic chambers are designed to do two things: to keep outside sound outside and to absorb reflected sound inside,β says Pavel Zahorik, professor of communication sciences and disorders. βThis allows us to make acoustical measurements that are highly accurate and precise, by limiting background noise and reflected sound.β
Precision is critical in Zahorikβs research.
An expert in hearing devices and technologies, hearing science and psychoacoustics, heβs part of ΒιΆΉΣ³»΄«Γ½βs growing , which in just two years ago has attracted some of the nationβs top hearing scientists to the College of Health Professions and Sciences.
In the new chamber, Zahorik will focus on improving hearing aids and listening devices, and learning more about how the shape of our ears and heads impacts how we hear.
Fine-Tuning Tech
Hearing loss is far from rare. According to the National Institutes of Health (NIH), approximately 15% of American adults β roughly 37.5 million people β report some trouble hearing. Among adults ages 65 to 74, roughly a third have hearing loss in one or both ears.
The effects extend well beyond missed conversations. Untreated hearing loss has been linked to higher rates of depression, increased risks of falls and even a greater likelihood of developing dementia.
By stripping away stray noise, Zahorik can ensure the devices designed to restore hearing are as accurate, effective, and life-changing as possible. To do that, inside of the anechoic chamber, every inch of the walls and ceiling is covered in sound-absorbing foam wedges (that look not unlike oversized monochromatic Monopoly houses) affixed at alternating angels. The floor is a steel mesh grid suspended over a layer of the same wall-to-wall wedges, swallowing stray sound waves before they can ricochet.
Anechoic derives from the Greek words meaning βwithout echo,β and the chamber delivers just that.
It may seem like overkill, but for manufacturers developing everything from hearing aids and AirPods to car communication systems, antennas and loudspeakers, quality and consistency depend on this level of acoustic control.
In fact, the first anechoic chamber was built to improve high-altitude military communication during World War II. Today, theyβre used to test everything from telecommunications and aerodynamics to medical devices, including MRI machines and pacemakers.
The one at ΒιΆΉΣ³»΄«Γ½ brings the distinctive designation of being devoted solely to research human health.
For Your Listening Pleasure
According to the NIH, an estimated 28.8 million U.S. adults could benefit from hearing aids. Yet the way we test these devices hasnβt always matched the way we actually use them.
Traditionally, hearing aids are placed inside a testing box fitted with loudspeakers. Researchers measure output and distortion in a controlled environment. Itβs accurate β but itβs also artificial.
Ears arenβt boxes.
They have unique curves and angles and sit on heads of different shapes and sizes. Each ridge and contour subtly bends incoming sound before it reaches the eardrum, changing each individualβs response to how they hear.
Inside the anechoic chamber, Zahorik can test [hearing aid] devices the way theyβre meant to function: in ears.
Inside the anechoic chamber, Zahorik can test devices the way theyβre meant to function: in ears.
Using both mannequins and human participants, he can measure how sound behaves in real anatomical context β how it interacts acoustically with the head and ears before sound information ultimately reaches the brain.
βEveryoneβs ears and heads are shaped differently, meaning acoustics are different for different people,β he says. βUnderstanding how the brain processes that different acoustical information could be really important for improving hearing.β
Zahorikβs longtime collaboration with Sonova β a global manufacturer of hearing aids, cochlear implants and wireless communication systems β builds upon this principle. By capturing cleaner, more realistic measurements, Zahorik hopes to refine how these devices amplify sound for users in everyday environments.
Because hearing isnβt just about volume.
Itβs also about space: direction and distance.
Itβs how we know a voice is behind us, a siren is blocks away or a friend is calling from across the room.
Zahorik has been fascinated by that puzzle ever since he was an undergraduate. A course on perception introduced him to the psychology of vision, but as a music enthusiast who dabbled in production, he was more interested in sound. His professor connected him with a researcher studying virtual sound simulation, and Zahorik volunteered for a study inside an anechoic chamber.
Blindfolded, he was led into the silent room. He sat there as a speaker emitted sounds and moved around him. His task was to say where he heard the sounds.
He was accurate in identifying direction. Distance, however, was another story.
βFor the longest time, I thought I was in this huge space, and that the sounds were quite far away,β he says. βBut when they took the blindfold off, I realized the space wasnβt very big at all. It was actually smaller than the chamber we have here.β
Without sight and echoes, the room distorted his sense of scale. That was in the late 1980s, and while technology has advanced dramatically since then, some of our understanding of auditory perception has not.
βWe still donβt know, for example, exactly how our brain decodes acoustical information to represent space,β says Zahorik, a self-described sound nerd whose office setup includes state-of-the-art headphones and microphones. βWe still donβt know how it is we know sounds are coming from a particular location and distance, and how the acoustical environment can change these perceptions.β
βThink of it like creating a 3D scan β but for sound.β β Pavel Zahorik, ΒιΆΉΣ³»΄«Γ½ researcher
The new chamber will eventually help probe those questions. For now, the room has one loudspeaker, but the plan is to install a movable speaker arc that will allow researchers to measure acoustical responses from nearly any position around a listener.
βThink of it like creating a 3D scan β but for sound,β Zahorik says.
And just as 3D imaging has transformed how we see, measure and interact with the physical world, the discoveries made in the quietest place on campus will help transform how we hear β resonating far beyond the chamberβs foam-lined walls.
