In the early days, hearing aids were basic amplifiers with limited features and poor sound quality, often causing issues like whistling or clicks. However, demand led to significant investment in research and development.
Currently, over 430 million people worldwide need hearing rehabilitation, with the number expected to rise to over 700 million by 2050. Additionally, over 1 billion young adults are at risk of hearing loss due to unsafe listening habits, especially in noisy recreational settings like nightclubs and concerts.
WSAudiology (WSA), a leading manufacturer of hearing aids, strives to improve sound quality through small, tech-rich devices. WSA’s Chief R&D Officer, Stefan Menzl, says, "We try to make our hearing aids as small as possible. Some of them are completely invisible. We try to hide them behind the ear or in the ear, so people don’t see them." Their Signia Active Pro is designed to look like an earbud rather than a hearing aid, aiming to reduce the stigma associated with hearing loss. WSA leverages state-of-the-art technologies and laboratories to meet the diverse needs of hearing aid users in a highly competitive global market.
Building products that interact with invisible forces
Hearing is the process of transforming sound vibrations into nerve impulses, which the brain interprets as sound, selecting the right signals and suppressing interference. Hearing impairment affects both this transformation and the brain’s ability to suppress unwanted sounds.
This creates design challenges for hearing aid manufacturers. “We try to make louder what needs to be louder, but not amplify sounds that don’t need to be loud,” says Stefan Menzl, WSA’s Chief R&D Officer, illustrating the complexity of hearing in noisy environments like restaurants.
Designers also have to account for electromagnetic interference, like the old mobile phone and car radio noise. “That’s one of the beauties of the simulation work we do,” Menzl explains. “We know whether a device works before we’ve completed the design, which is crucial for us.”
WSA uses SIMULIA’s CST Studio Suite to digitally test designs, saving time and money. “If you try everything in the real world, it will take forever,” Menzl says. Simulation allows them to test various shapes of circuit boards, hearing aids, and microphone inlets before physical testing, leading to faster development.
Hearing aids also use wireless technology, including Bluetooth, to stream audio directly from devices. “The only way you can really predict how an antenna works is by simulation,” says WSA Head of Wireless Systems Thomas Fischer. “Hearing aid antennas are cutting-edge technology—close to the ear and within a tiny device.”
SIMULIA’s tools allow testing for various scenarios, including PCB and electromagnetic simulations, and even drop testing. “You can drop it from the ear to a hard concrete floor,” says Menzl. Only after digital testing and design modifications does a product move to physical lab testing.
To achieve high-quality sound, Fischer adds, “We simulate our IC design to know how it works before we get the first chip.” These simulations help identify and avoid issues in future designs, with each cycle improving their workflow.
"Simulation enables us to push ahead. I love simulation because it enables faster development, more precise development, and lets us stretch to the limits of physics. It's really cool."
Minimize physical testing and speed up product development with Simulia
During development, hearing aid performance is tested both digitally and physically, with key metrics like amplification, frequency response, distortion, noise, and antenna performance. WSA conducts extensive physical testing in their labs, including drop tests, acoustics, and high-speed cameras. “We can create a restaurant situation in a controlled way to listen to different settings of the hearing aid,” says Stefan Menzl, WSA’s Chief R&D Officer. They also test products in various temperatures and humidity levels, with their environment labs able to go from –20°C to 40°C in under a minute.
Menzl recalls the early days when much of the testing was done physically. “Many, many iterations were done to make things work, especially the electronics,” he says. With SIMULIA’s simulation tools, WSA can now speed up design and testing, making devices smaller, more reliable, and longer-lasting.
“Simulation enables us to push ahead,” Menzl adds. “I love simulation because it enables faster, more precise development and lets us stretch to the limits of physics. It’s really cool.”
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