National Physical Laboratory

Underwater Acoustics Transducer Services

In underwater acoustics, accurate measurements are the key to successful product development and high-quality test services. The worldwide adoption of ISO 9000 means that users will increasingly demand that measurements have traceability to internationally- recognised standards. Let NPL's calibration services provide you with that essential traceability.

NPL's Underwater Acoustics Services set the Standard

NPL operates unique underwater acoustics facilities. Using one or more of the open-tank facility, air-pistonphone, Acoustic Pressure Vessel or Wraysbury open-water facility, we will be able to provide a complete characterisation of your transducers and sonar systems under a variety of conditions.

Description Frequency Range
Free-field hydrophone sensitivity
UKAS accredited
Traceable to primary free-field reciprocity calibrations (1 kHz to 500 kHz) or optical interferometry (500 kHz to 20 MHz) 1 kHz to 20 MHz
Pressure sensitivity of hydrophones (low-frequency)
UKAS accredited
Calibration using an air pistonphone and reference NPL microphone 25 Hz to 400 Hz
Calibration and testing of underwater acoustic transducers at simulated ocean conditions Measurements performed in the NPL Acoustic Pressure Vessel at water temperatures ranging from 2 °C to 35 °C and hydrostatic pressures ranging from 0.1 MPa to 7 MPa From a few kilohertz to 500 kHz
Directional response measurement
UKAS accredited
Directional response in vertical and horizontal planes over 360° using precision positioning system From 1 kHz upward
Impedance measurement Electrical impedance/admittance measurements of transducers DC to 20 MHz
Free field calibration of transducers and hydrophones
UKAS accredited 1 kHz to 350 kHz
Calibration of underwater acoustic transducers and at the Wraysbury open-water facility 250 Hz to 350 kHz
Sonar system characterisation Full system characterisation for sonars, including transmit and receive sensitivity, electrical impedance, directional response, etc. 250 Hz to 350 kHz


Customised Measurements

NPL provides customised acoustic measurements to satisfy a range of requirements in research and development, manufacturing, and calibration and testing, for example:

  • Characterisation of high-frequency sonars, including nearfield measurements by hydrophone scanning or optical vibrometry
  • Testing of experimental transducers during the early stages of development
  • In the medical field, compliance testing to medical device output standards

Contact us to discuss your specific measurement requirements.

Further Information / Contacts:

Last Updated: 16 Mar 2015
Created: 6 Jun 2007


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