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Research at CRITIAS

For more than a decade, the ÉTS-EERS Industrial Research Chair in In-Ear Technologies (CRITIAS) has focused on developing technologies for the human ear, “intelligent” hearing protection and communication in noise, ranging from the integration of in-ear brain-computer interfaces to on-board hearing diagnosis, and including fundamental studies related to neuro-sensory stimulation and micro-energy harvesting, working in collaboration with experts in their respective fields.

Areas of research

The Chair’s research activities are primarily focused on five areas:

Hearing protection:

  • Passive hearing protection
  • Adjustment testing
  • Sound reproduction
  • In-ear dosimetry
  • Digital audio filtering
  • Active noise control
  • Oto-acoustic emissions

Communication in noise:

  • Hearing devices
  • Speech capture


  • Measurement of biosignals
  • Measurement of ambient and medical conditions
  • Dynamic measurements
  • Physiological sensors
  • Deformation of the ear canal
  • Electrophysiology


  • Electrical stimulation
  • Light stimulation
  • Mechanical stimulation
  • Thermal stimulation
  • Magnetic stimulation

Energy harvesting

  • Micro-energy harvesting

Benefits of the Chair’s activities

  • Development of the knowledge and technologies required for the creation of a bionic earpiece that can become a true brain-computer interface. The earpiece will integrate all of the functionalities necessary to accomplish the following into a unique system:
    • Protect the wearer against harmful noises while enhancing the perception of speech and useful signals;
    • Allow for in-ear communication: Sending and receiving within the same ear;
    • Allow for the measurement of physiological signals within an occluded ear, along with the measurement of brain waves through electroencephalography (EEG).
  • Integration of technologies developed by the Chair into the EERS SonoFit® solution (earmold that instantly adjusts to the wearer’s ear).
  • Development of innovative hearing products for the general public and the industrial, military and medical markets.
  • The fit-testing technology produced by the initial collaboration between Sonomax and ÉTS has now been commercialized worldwide by 3M, an American multinational company, and is enjoying ongoing technological and commercial success. This individual fit-testing technology was recognized in 2008 by US federal agencies as an “Emerging Trend” in the NIOSH-NHCA-OSHA Alliance Best Practice Bulletin, and 3M has regularly won awards over the years, including the prestigious Occupational Health & Safety New Product of the Year Award in 2015 for their rebranded “EARfit” fit-testing system. The fit-testing approach to hearing protectors dramatically modified hearing conservation practices in North America over recent years, and is now part of most hearing-loss prevention programs around the world, protecting tens of million workers on a daily basis.