In a groundbreaking development, scientists at EPFL (École Polytechnique Fédérale de Lausanne) have harnessed the power of ionized air to create a revolutionary plasma loudspeaker that not only generates sound but also absorbs it. This innovative technology, known as the "plasmacoustic metalayer," has the potential to revolutionize noise reduction techniques. [1]

Figure 1. Plasma Valves Dark.

Figure 1 shows the plasma valves dark. Traditional loudspeakers rely on membranes to produce sound, but these membranes come with limitations, especially when it comes to absorbing sound. The EPFL scientists aimed to overcome these limitations by eliminating the heavy membrane and using ionized air instead. By ionizing a thin layer of air between parallel wires, they created a plasmacoustic metalayer that can be controlled to cancel out noise effectively. [1]

The plasmacoustic metalayer allows for efficient sound absorption across a wide frequency range, including high frequencies. Its lightweight nature and fast response time make it highly versatile and capable of canceling out rapidly changing sounds. Unlike passive noise reduction technologies, this active plasma absorber can be tuned to interact with and cancel out sound over a broad bandwidth. [1]

One of the remarkable advantages of the plasmacoustic metalayer is its compactness. The EPFL scientists demonstrated perfect sound absorption, with 100% of the incoming sound intensity being absorbed by the metalayer. This compactness makes the plasma absorber far more space-efficient than traditional solutions like absorbing walls. For example, at a low audible sound frequency of 20 Hz, where the sonic wavelength is 17 meters long, the plasma layer only needs to be 17 mm thick, while conventional solutions would require a thickness of at least 4 meters. [1]

The EPFL has joined forces with Sonexos SA, a Swiss-based audio technology company, to further develop active sound absorbers based on the plasmacoustic metalayer concept. Together, they aim to provide efficient noise reduction solutions for various applications, including automotive, consumer, commercial, and industrial sectors. [1]

This breakthrough in using ionized air to actively reduce noise holds significant potential for transforming the way we tackle noise pollution. The ethereal and lightweight nature of the plasmacoustic metalayer opens up new frontiers in noise control, particularly in situations where space and weight are crucial factors, especially at low frequencies. With ongoing research and collaboration, this technology could pave the way for quieter and more peaceful environments in numerous settings. [1]

References:

1. https://www.eurekalert.org/news-releases/990022

Cite this article:

Hana M (2023), Electrifying Silence: Harnessing Ionization to Actively Reduce Noise Pollution, AnaTechmaz, pp.446