Welcome to 麻豆原创鈥檚聽 anechoic chamber.

Located in the 麻豆原创 Innovative Center, the 217-square-foot chamber is not big by any means 鈥� but the impact it will play in understanding and improving hearing certainly is.

鈥淎nechoic chambers are designed to do two things: to keep outside sound outside and to absorb reflected sound inside,鈥� says Pavel Zahorik, professor of communication sciences and disorders. 鈥淭his allows us to make acoustical measurements that are highly accurate and precise, by limiting background noise and reflected sound.鈥�

Precision is critical in Zahorik鈥檚 research.

An expert in hearing devices and technologies, hearing science and psychoacoustics, he鈥檚 part of 麻豆原创鈥檚 growing , which in just two years ago has attracted some of the nation鈥檚 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 鈥� roughly 37.5 million people 鈥� 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 鈥渨ithout echo,鈥� 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, they鈥檙e used to test everything from telecommunications and aerodynamics to medical devices, including MRI machines and pacemakers.

The one at 麻豆原创 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 hasn鈥檛 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. It鈥檚 accurate 鈥� but it鈥檚 also artificial.

Ears aren鈥檛 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 individual鈥檚 response to how they hear.

Inside the anechoic chamber, Zahorik can test [hearing aid] devices the way they鈥檙e meant to function: in ears.

Inside the anechoic chamber, Zahorik can test devices the way they鈥檙e meant to function: in ears.

Using both mannequins and human participants, he can measure how sound behaves in real anatomical context 鈥� how it interacts acoustically with the head and ears before sound information ultimately reaches the brain.

鈥淓veryone鈥檚 ears and heads are shaped differently, meaning acoustics are different for different people,鈥� he says. 鈥淯nderstanding how the brain processes that different acoustical information could be really important for improving hearing.鈥�

Zahorik鈥檚 longtime collaboration with Sonova 鈥� a global manufacturer of hearing aids, cochlear implants and wireless communication systems 鈥� 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 isn鈥檛 just about volume.

It鈥檚 also about space: direction and distance.

It鈥檚 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.

鈥淔or the longest time, I thought I was in this huge space, and that the sounds were quite far away,鈥� he says. 鈥淏ut when they took the blindfold off, I realized the space wasn鈥檛 very big at all. It was actually smaller than the chamber we have here.鈥�

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.

鈥淲e still don鈥檛 know, for example, exactly how our brain decodes acoustical information to represent space,鈥� says Zahorik, a self-described sound nerd whose office setup includes state-of-the-art headphones and microphones. 鈥淲e still don鈥檛 know how it is we know sounds are coming from a particular location and distance, and how the acoustical environment can change these perceptions.鈥�

鈥淭hink of it like creating a 3D scan 鈥� but for sound.鈥� 鈥� Pavel Zahorik, 麻豆原创 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.

鈥淭hink of it like creating a 3D scan 鈥� but for sound,鈥澛燴ahorik 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 鈥� resonating far beyond the chamber鈥檚 foam-lined walls.

To better understand Assistant Professor Hamzeh Ghasemzadeh and his work, he goes back to a childhood memory of broken toys. Within hours of receiving little robotic figures or remote-control cars, he鈥檇 dissembled what had once been a carefully crafted package of technology. To him, sitting among the remnants of a new gift meant he was sitting in a circle of fun.

鈥淢y favorite game was to take the toys apart to see how they work and then try to put them back together,鈥� Ghasemzadeh says. 鈥淢y parents saw my curiosity as a great thing.鈥�

“This is why I came to 麻豆原创. I鈥檝e been able to jump right in and address mysteries that haven鈥檛 received much attention.”

That same curiosity now drives his research at , where he seeks to take apart discomforted voices, figuratively, so he can develop strategies to make each one whole again. Ghasemzadeh, who joined 麻豆原创 in late Summer 2025 and will teach in the school鈥檚 newly launched , has already secured one research project funded by the U.S. National Institutes of Health and is developing another.

鈥淭his is why I came to 麻豆原创,鈥� he says. 鈥淚鈥檝e been able to jump right in and address mysteries that haven鈥檛 received much attention until now.鈥�

A Common Problem Without Clear Answers

The first such mystery sounds quite straightforward: vocal fatigue, a common vocal complaint. Beneath the surface, however, it鈥檚 deceptive. Solutions have mostly evaded scientists, leaving vocal fatigue as an ongoing problem for many people who rely on their voices, like coaches, public speakers, singers and teachers. Many of Ghasemzadeh鈥檚 colleagues experience the very throat discomfort that he鈥檚 deconstructing during the funded project just underway.

“We want to collect … multi-modal data and use machine learning models to analyze [vocal fatigue] and develop recommendations for each person.”

鈥淪ome instructors get vocal fatigue quickly, some get it slowly and some don鈥檛 get it at all,鈥� he says. 鈥淭here鈥檚 a genetic component, but there are also behavioral components. How do they use their voice? How often do they use it? What about the environment where they鈥檙e using it? What about personality? We want to collect such comprehensive multi-modal data and use machine learning models to analyze it and develop recommendations for each person.鈥�

The recommendations might include pacing voice usage, projecting the voice efficiently and allowing the voice to recover. Ghasemzadeh envisions this model being predictive and 鈥� this is the part he stresses most 鈥� personalized.

鈥淭he approach to general medicine started with an assumption that while we鈥檙e different on the outside, we are very similar inside. Patients with similar ailments took the same medications and [the] same dosages. But we now know that people don鈥檛 always respond to pills the same way. If we can quantify how we鈥檙e different inside, we can create a computational model to predict responses to medications and optimize treatment plans.鈥�

To integrate artificial intelligence (AI) into vocal fatigue solutions, subjects in Ghasemzadeh鈥檚 study will wear sensors that track how and where they use their voices. He鈥檒l prompt them to perform specific vocal tasks and monitor their phonatory function throughout the day. The AI model will analyze these patterns in real time to identify early signs of vocal strain and predict when fatigue is likely to occur.

“We are different. Every prescribed solution should be different, too.”

Participants will also visit his lab at the in Central Florida Research Park, where specialists will collect imaging, aerodynamic and acoustic data. The highly equipped facility brings together America鈥檚 leading hearing and voice scientists to develop new technologies and clinical tools for people with hearing loss or voice disorders.

With all of that in hand, including the technology, Ghasemzadeh and his team hope to unwind the mystery of vocal fatigue 鈥� one person at a time.

鈥淭hat鈥檚 the idea I want to put forward with every project,鈥� he says. 鈥淲e are different. Every prescribed solution should be different, too.鈥�

From Engineering to Human Connection

Many would think a toy-reassembling boy is destined to become an engineer. That鈥檚 what Ghasemzadeh thought, too. He earned bachelor鈥檚 and master鈥檚 degrees in electrical engineering and began his career with a focus on telecommunications and signal processing.

鈥淭here was something important missing,鈥� he says. 鈥淗uman connection.鈥�

“Speech became my research interest because … it sets us apart as a species and as individuals.”

He crossed paths with a close friend who mentioned his own research in a field Ghasemzadeh was vaguely familiar with: communication sciences and disorders. The conversation sparked Ghasemzadeh’s enthusiasm for applying his expertise in areas such as signal processing to personally help others.

鈥淪peech became my research interest because it鈥檚 the signal we predominantly use to communicate,鈥� he says. 鈥淚t sets us apart as a species and as individuals.鈥�

For example, it鈥檚 quite easy to identify Ghasemzadeh without even seeing him. He sounds young yet intelligent enough to have dual doctoral degrees. There鈥檚 an inflection of humility in his voice. The curiosity is always there, too. In fact, his peers have noticed, from his work, what his parents noticed among his broken toys: his curiosity leading to great things. Shortly after arriving at 麻豆原创, the American Speech-Language-Hearing Association chose Ghasemzadeh for its Early Career Contributions in Research Award.

鈥淚t鈥檚 also a reminder that I鈥檓 early in my career,鈥� he says, 鈥渁nd the sky is the limit.鈥�

At the center of his work as a principal investigator is a belief that progress doesn鈥檛 happen alone, but through teamwork.

鈥淵ou have to surround yourself with different skillsets, all of us willing to take things apart that have never been taken apart, with everyone focused on one goal,鈥� Ghasemzadeh says. 鈥淲hen you win, I win and everyone wins.鈥�

Research reported in this publication was supported by the National Institute on Deafness and Other Communication Disorders of the National Institutes of Health under award number R00DC021235. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

The irony is obvious. Awan is a speech scientist. Through research, he helps speech pathologists improve clinical services for people with speech disorders. His momentary vocal discomfort creates an opening to discuss 鈥� and simplify 鈥� his most recent groundbreaking work.

鈥淏eing hoarse isn鈥檛 necessarily a problem unless it persists for more than two weeks,鈥� Awan says. 鈥淲hen it disrupts daily life beyond an irritation, medical referral and potential speech pathology services come into play. The goal of my research is to help speech pathologists more easily determine the 鈥榳hy鈥� regarding voice disorders.鈥�

With his current research, Awan and his team can literally hear the future of speech pathology. They can see the future, too. In fact, Awan can hold it in the palm of his hand. For more than 30 years, the research professor in 麻豆原创鈥檚 School of Communication Sciences and Disorders has focused his lifelong interest in acoustics and his expertise in voice evaluation to find the root causes of communication disorders that affect as many as one in ten people in the U.S. One of the unsolved problems in voice-disorder assessments enticed him out of retirement so he could pursue a simple solution, this time with a $3.12 million dollar grant funded by the National Institute on Deafness and Other Communication Disorders and a team of six interdisciplinary researchers from three universities.

Today, Awan and his team believe they have an answer: a whistle. Not a cumbersome costly machine, but a vortex whistle small enough to fit into a shirt pocket. In its final form, it will be biodegradable, disposable, and affordable. It will have no moving parts and doesn鈥檛 need to be powered. Awan envisions the whistles being as readily available as a bag of dental-floss picks. Accompanying software that captures and analyzes the vortex whistle tone completes the system.

He also sees them changing lives, soon.

鈥淥ur version of the vortex whistle addresses a widely known deficit that speech pathologists deal with in terms of accurately assessing voice-disordered patients,鈥� Awan says.

To uncomplicate the picture, he compares the evaluation of voice to the evaluation of vision. 鈥淚magine if your optometrist said, 鈥榃e really should do one other test to make sure we鈥檙e on the right track with your prescription 鈥� but we don鈥檛 have the equipment because it鈥檚 too expensive.鈥� That鈥檚 the scenario what we want to change in speech pathology.鈥�

Voice production, Awan says, combines the physical laryngeal component (the 鈥渧oice box鈥�) with respiratory airflow. To properly assess and treat patients with voice disorders, four key areas need to be measured:

1. Perceptual analysis. 鈥淭he therapist listens to the patient, describes the voice and categorizes it. This requires training but no additional instrumentation.鈥�
2. Visual analysis. 鈥淚mages of vocal folds, often referred to as 鈥榲ocal cords鈥�, are obtained by a laryngologist or an associated professional under the supervision of a laryngologist).鈥�
3. Acoustic analysis. 鈥淭he acoustic signal is recorded and analyzed for measurements related to a potential voice difference and the severity of the problem. Almost all speech/voice clinicians have access to a computer, microphone and analysis software capable of doing this type of measurement.鈥�

And that leads to number four, the critical link that鈥檚 usually missing.

鈥淎erodynamics,鈥� Awan says. 鈥淲hen you produce voice, the vocal folds vibrate because of air coming up from the lungs. The voice is dependent on the respiratory system鈥檚 capacity and ability to generate air flow and pressure. If there鈥檚 a deficit in producing or controlling respiratory forces, the voice is often affected. There could be an underlying neurological problem, or a medical issue like asthma or COPD that may require medical treatment or voice therapy. Until now, the respiratory element in speech has been overlooked because there鈥檚 been no low-cost, accurate, available method to measure aerodynamics. This vortex whistle, with easy-to-use software, will make it possible in a day-to-day clear-cut fashion.鈥�

Awan talks about how this project came about.

鈥淭his all started at a voice disorder conference,鈥� he says. 鈥淧eople were discussing the fact there were no low-cost tools to measure aerodynamics as it relates to voice. In my mind, I knew there must be something out there that could be reimagined.鈥�

Awan, the speech scientist who once thought following his graduate work in the U.S. that he might return to his childhood home in London, Ontario, Canada, to pursue a career in music, used his knowledge in acoustics to consider a few ideas. A flute? A referee鈥檚 whistle?

鈥淣either of them produces a sound specifically related to the amount of air flow going into them,鈥� Awan says. 鈥淭hen I became aware of the vortex whistle. It has no moving parts. Air enters the cylinder, which forces the air to spiral and exert pressure against the walls of the cylinder before exiting. This creates a signal that has a pitch and frequency that are directly proportional to the amount of air flowing into the whistle. That鈥檚 the principle.鈥�

The frequency of the vortex whistle sound wave can then be converted to measurements of airflow and volume.

The vortex whistle鈥檚 potential is why Awan took up his friend and colleague, 麻豆原创 Professor David Eddins, on an offer to unretire, form a team, and work toward applying the science. The NIDCD-funded grant has accelerated the progress. At Purdue, his son, Jordan Awan, leads data analysis while aerodynamics engineer Jun Chen works on modifications of the whistle for specific tasks. At Emory University, Amanda Gillespie conducts studies with voice disordered human subjects. And at 麻豆原创, Awan, Eddins and Assistant Professor Victoria McKenna have access to lab space built to spec in the Communication Technologies Research Center in the 麻豆原创 Innovative Center 鈥� sound-treated booths, an anechoic chamber and a reception area for subjects participating in tests. In the same building are a speech and hearing clinic and capabilities for 3D printing and simulation.

鈥淔or the vortex whistle to be ready for use, its construction has to be very precise,鈥� Awan says. 鈥淚t also requires software development to accurately capture and analyze a somewhat difficult soundwave. We鈥檙e getting close.鈥�

The Journal of Voice has already published the study from Awan鈥檚 team as an award-winning cover story. Since then, various versions of the whistle have been computer-modeled and 3D printed. The modifications are being tested in the first of three large-scale human subject studies. The second study, in 2025, will look at subjects from 5 to 90 years old to see how well the vortex whistle works to document potential changes in measurements of respiratory volume and airflow during voice production across the lifespan. And the final study will utilize the vortex whistle as a treatment-outcome measure before and after medical procedures for vocal-fold paralysis.

From there, the application could be far-reaching.

鈥淢y hope with the vortex whistle,鈥� Awan says, 鈥渋s that we start with speech and voice-disordered patients, and then identify its usefulness in other areas of medicine and associated areas such as exercise science and sports physiology. By making it affordable and accessible, there鈥檚 no limit to how many people can ultimately benefit from it.鈥�