Researchers at the EPFL Acoustic Group are pushing the boundaries of noise cancellation technology by exploring new avenues for application. While active noise canceling (ANC) has proven effective in headphones and vehicles, implementing it on a room-scale poses challenges as low-frequency sounds tend to escape cancellation. Fortunately, a promising solution has emerged in the form of plasma-based noise-canceling technology.
Traditionally, ANC relies on measuring the pressure of sound waves produced by speakers and then emitting an opposing signal to effectively neutralize the waves, thereby minimizing noise. However, extending ANC to a room-sized environment has required the use of large, cumbersome speaker arrays. In contrast, EPFL researchers have made significant progress in developing a more lightweight approach to address this noise issue.
In their quest to mitigate and eliminate noise, the EPFL embarked on a series of experiments involving ultra-thin plasma-based ionic speakers. These speakers offer a lightweight, uncomplicated, and cost-effective alternative. They operate on a principle similar to ionic propulsion systems, which utilize an electric field to ionize the surrounding air, generating positively and negatively charged particles. These particles are then accelerated and directed toward the ambient air, generating pressure waves.
One advantage of these plasma-based ionic speakers is the ability to adjust the applied voltage, enabling instant control over the volume of air being propelled. While these small, inexpensive speakers may not cater to audiophiles seeking top-tier sound quality, they do provide a solution that reduces the weight associated with traditional speaker membranes commonly used in such systems.
The utilization of plasma-based noise-canceling technology holds significant promise due to its ability to effectively cancel both high-frequency and low-frequency wavelengths. EPFL researchers have discovered that these new speakers can achieve impressive results in canceling out lower frequency sounds using a mere 17 mm (0.6 inches) piece of material. In comparison, conventional methods such as noise-reduction foams or sound-absorbing walls require a much bulkier setup, often around 4 m (13 feet) in thickness. This breakthrough opens up possibilities for creating noise-canceling environments in various settings such as rooms, airplanes, and vehicles.
While immediate implementation may not be imminent, the field of audio technology is poised to make significant advancements with the integration of plasma-based noise cancellation and MIT’s paper-thin speakers. These innovations signal exciting progress and potential in the realm of noise-cancellation technology.