DEMASK partners use different recorders to measure underwater sound. Good calibration of the instruments is crucial to have comparable results from all these instruments. Therefore, a workshop was organised to share knowledge and exchange techniques. WaterProof BV, a company specialised in the development and deployment of underwater sound measurement technology, was hired by Rijkswaterstaat to organise a joint calibration workshop for the DEMASK partners. The workshop was held at TNO in The Hague in February 2025. It provided DEMASK partners with the opportunity to test and calibrate their autonomous recorders in TNO’s acoustic basin.
Purpose of the workshop
The DEMASK project frequently uses underwater sound measuring equipment. To ensure accurate and comparable data a calibration session was organized. TNO facilitated the workshop by providing a controlled test environment where participants could deploy their sensors and compare their recorded sound levels with precise reference measurements. This allowed them to check how well their equipment was performing and identify any necessary adjustments.
Calibration procedure
To achieve this, a standardised calibration method (based on IEC 60565-1) was used. TNO set up sound projectors that transmitted frequency-swept sine signals at different frequencies in the water. First, a highly accurate reference hydrophone recorded these signals to establish a baseline. Then, the participants' hydrophones were placed in the same position to capture the same sounds. By comparing the results, participants could assess and fine-tune their measurement systems for greater reliability.
Boosting accuracy through collaboration
Each participant is responsible for processing their own data as well as cross-checking at least one other dataset. WaterProof has provided an FTP site for data exchange, and results will be discussed in the future. The workshop provided valuable insights and strengthened collaboration among partners, ensuring improved accuracy in future underwater sound measurements.
Stay informed by subscribing to our newsletter or following us on LinkedIn