Sonexos Raises CHF 5M Pre-Series A to Industrialize Plasma Noise Control

Swiss startup Sonexos SA has raised CHF 5 million (approx. $6.1M / €5.4M) in Pre-Series A funding to push its solid-state noise-control technology from engineered prototypes to qualified industrial products. Valquest Partners led the round, with participation from Robert Bosch Venture Capital GmbH (Bosch Ventures), industry angels, and private investors.

The Lausanne-based company builds what it calls the Plasmacoustic Metalayer — a patented, software-controlled layer of plasma packaged into sealed, inert-gas-filled Plasmapanel modules and driven by Plasmadrive electronics. The platform absorbs sound at a surface without bulky passive treatments or moving parts. That's the core pitch: replace mechanical silence with software-tuned plasma.

Who runs Sonexos?

Founder and CEO Mark Donaldson leads the company, alongside CTO Dr. Stanislav Sergeev and COO Andrea Onetti. The team targets low-frequency noise — the hardest kind to damp — generated by fans, compressors, and motors.

Its customers are global OEMs across three markets: domestic appliances, HVAC equipment, and AI data-center cooling. The last one matters commercially. AI data centers run dense racks of high-power chips, and cooling fans at scale produce exactly the low-frequency noise Sonexos says its technology can absorb without passive silencers that eat airflow and space.

What will the CHF 5M fund?

The company laid out a concrete allocation for the new money:

• The transition from engineered prototypes to qualified industrial products
• Funding for customer integration, reliability testing, qualification, and regulatory compliance
• Expansion of its engineering and applications teams in Switzerland and internationally
• Broadening international protection of its intellectual property

The regulatory-compliance line signals what's ahead: Sonexos must prove its Plasmapanel modules can survive industrial qualification cycles before OEMs design them into shipping products. Customer integration funding suggests early OEM partners are already testing the modules in real hardware.

The IP item cuts both ways. The Plasmacoustic Metalayer is patented, and Sonexos plans to broaden that protection internationally — a defensive move as it moves from lab-grade prototypes toward products its OEM customers will embed in appliances and cooling systems sold worldwide.

Why does Bosch Ventures' involvement matter?

Robert Bosch Venture Capital's participation puts a strategic corporate investor behind the technology. Bosch sits inside the exact industrial ecosystem Sonexos sells into — motors, appliances, and thermal systems — making the firm a potential channel as much as a shareholder.

The involvement of Valquest Partners, a Swiss private equity house, plus unnamed industry angels, also suggests the round drew backers who know industrial hardware timelines. Moving plasma-based acoustics from prototype to qualified product isn't a software-speed exercise.

What's next?

Sonexos hasn't disclosed a valuation or a timeline for Series A. What the CHF 5M buys is the industrialization step: qualification, compliance, team growth, and international patents. If the Plasmapanel modules pass reliability testing and win design slots at appliance and data-center-cooling OEMs, the company will arrive at its next raise with customer validation — the metric hardware investors price most.

The date of the announcement: 26/10/2026, per FinSMEs.