The low-frequency hum thrown off by cooling fans and compressors is the one noise acoustic foam cannot touch. As frequencies drop, conventional treatments grow bulkier and begin to starve airflow. A startup in Lausanne wants to soak up that sound with a thin layer of plasma instead.
Sonexos has drawn CHF 5M, roughly €5.4M, in pre-Series A equity. Valquest Partners led, with Robert Bosch Venture Capital and industry angels chipping in, and Valquest founder Fadi Noureddine takes a board seat.
What the patent covers is the Plasmacoustic Metalayer: a thin, software-driven plasma field that absorbs noise right where it hits a wall or duct. Nothing inside it moves and it adds barely any weight. In the firm’s own tests, prototype units notched reductions reaching 20 dB for ventilation systems and 16 dB for domestic appliances.
From prototypes to a 2028 production line
The cash pays for the move from engineered prototypes to qualified industrial products, with first series production penciled in for early 2028. Sonexos runs paid integration programs with appliance and HVAC manufacturers worldwide and says its most advanced work is nearing appliance-level design-in.
The technology is licensed out of EPFL. Chief executive Mark Donaldson brings three decades in active noise control, including time at SoundChip, later bought by DSP Group. STMicroelectronics is backing low-power electronics through its startup program, and a collaboration with Roj, a Vandewiele subsidiary, gives the firm a manufacturing route for European OEM programs.
AI infrastructure supplies the tailwind. Larger data halls run fans continuously, and noise caps can block round-the-clock operation. Sonexos is developing a radial silencer that wraps around a fan discharge without impeding airflow, with Italian fan maker SIT as its first certified partner and a working demonstrator due at CES 2027.
