Hearing loss is a major problem around the world, especially in loud work environments and at events like concerts.
Foam earplugs and bulky ear protectors can help, but they have drawbacks.
Foam earplugs, for instance, often make music sound muffled and bass-heavy, while large ear protectors can feel uncomfortable and prevent users from hearing what’s going on around them.
As a result, many people remove their ear protection, risking permanent hearing damage.
To address this, scientists at SINTEF, a Norwegian research organization, partnered with Minuendo, a company specializing in hearing protection, to develop a new type of earplug.
Their creation combines the best features of both passive and active ear protectors.
These innovative earplugs are small and comfortable, allowing users to control the volume without distorting sound quality, thanks to advanced piezoelectric microtechnology.
Traditional ear protectors are either passive (like foam earplugs) or active (like noise-canceling headphones).
Passive earplugs work by blocking noise without electronics, while active protectors use microphones and speakers to filter sound.
Although active hearing protection is more advanced, it can be bulky, uncomfortable, and expensive. Passive protectors, on the other hand, lack the ability to adjust sound levels.
The new hybrid earplugs designed by SINTEF and Minuendo overcome these limitations. At the core of these earplugs is a tiny chip made using piezoelectric microelectromechanical systems, or piezoMEMS.
This piezoMEMS technology enables the earplugs to adjust volume levels without sound distortion. In simple terms, the earplug has tiny slits that can open and close, either letting sound through naturally or reducing its volume.
The earplugs allow the user to control the volume by adjusting these slits electronically, ranging from no reduction (0 dB) to a significant drop (40 dB).
At a higher voltage of 30 volts, the slits open to let sound through at full volume, while at lower voltages, they close to reduce sound. This volume control feature lets users enjoy clear sound at a safe, comfortable level without the muffling effect of traditional earplugs.
Not only does this earplug offer volume control, but it also works as a microphone and speaker. This is possible due to the piezoelectric material, which can convert sound vibrations into electrical signals and vice versa. This dual function could allow users to monitor external noise and adjust their earplug settings accordingly. This means the earplugs could adapt to different noise levels automatically, providing both hearing protection and sound clarity as needed.
The piezoMEMS technology in these earplugs is also incredibly energy-efficient, using only a few hundred nanowatts of power.
This low power consumption means smaller batteries and lighter earplugs, which could also make them more affordable in the future. The current prototype is about one-ninth the size of a coin, and researchers believe future models could shrink even more, making these earplugs even more compact and accessible.
These new earplugs represent a leap forward in hearing protection, blending safety, comfort, and sound quality in a single device. With the potential for mass production and a design that reduces power needs, these smart earplugs could become an affordable and essential tool for anyone exposed to loud environments, whether in a workplace, at concerts, or even at home.
