Final Report, 7 February 2005
Final report (NPL Report DQL-AC003) has been completed and circulated to participants. Further copies are available on request from
National Physical Laboratory
Acoustical Metrology Group
The principle objective of this project is to compare calibrations of bone-conduction measurement systems by national standards laboratories. Measurements will be made on an IEC 373 mechanical coupler and a type of bone vibrator commonly used within Europe at the eight common audiometric test frequencies between 250 Hz and 4 kHz.
The project will consist of two parts. The first part will be organised radially with NPL acting as the central laboratory, each participating laboratory will calibrate and use its own mechanical coupler system to make measurements on bone vibrators provided by NPL. The second part of the project will involve a subset of the partners measuring the mechanical impedance and force sensitivity of a mechanical coupler provided by NPL. These measurements will be made in a round-robin format.
The work will test the consistency of standards for bone-conduction audiometry within the EC and identify the cause of any anomalies and may identify ways of improving the design or method of use of the standard instruments employed.
NPL proposes to act as co-ordinator.