Swiss research institute Empa, in collaboration with materials manufacturer de Cavis, has introduced a breakthrough in acoustic materials: ultra-thin sound-absorbing panels made from mineral foams. These new panels are up to four times thinner than conventional options, making them ideal for space-constrained architectural settings without compromising performance.

Slim Design, Strong Performance

Traditional acoustic materials, such as rock wool or melamine foam, rely on thick layers to dampen low-frequency sounds. This often limits their use, especially in outdoor areas or narrow spaces. In contrast, Empa’s new absorbers—made from cement or gypsum-based foams—require just 5.5 centimeters of thickness to absorb typical traffic noise, ranging between 500 and 1000 Hertz.

Moreover, these mineral foams are weather-resistant, fireproof, and recyclable. They are easy to cut and install, making them a practical choice for both new builds and retrofit applications.

How the Technology Works

The panels consist of multiple porous layers with varying thickness and perforation. Each layer forces air and sound waves to travel a longer, winding path. This structure tricks the sound into behaving as if it’s moving through a much thicker material.

According to Empa researcher Bart Van Damme, the secret lies in combining large pores with thin pore walls. This design enhances absorption while keeping the panel lightweight and compact. Additionally, computer models help simulate air flow through the pores, allowing designers to adjust pore size and layering to target specific frequency ranges.

Tested in Real Urban Settings

In a pilot project with the City of Zurich, researchers installed 72 panels covering 12 square meters in a residential driveway. The results were promising. Sound levels dropped by up to 4 decibels, particularly noticeable when cars entered or exited the area. While performance at higher frequencies was slightly lower than that of rock wool, the mineral foams proved more effective at lower frequencies, where traditional materials often struggle.

Sustainable and Design-Friendly

These absorbers are not only functional but also aesthetically versatile. Because they’re made of the same materials as wall finishes, they integrate smoothly into interior spaces like stairwells, offices, cafeterias, and sports halls. They offer a clean, seamless look while improving acoustic comfort.

Looking ahead, Empa aims to scale production by partnering with industry. Although some manual work is still involved, the potential for wider adoption is significant—especially in locations where space, fire safety, and design are all important factors.

Source & photos: Empa