Primary Pressure Calibration of Laboratory Standard Microphones
For customers who require their measurement grade microphones to be calibrated to the highest possible accuracy, the NPL Acoustics group offers calibration by the internationally agreed reciprocity method. This service provides pressure sensitivity calibration for laboratory standard microphones (IEC type LS1 and LS2 microphones), which can be calibrated to the same measurement precision as NPL's own microphones that are used to establish the primary standard. This service is UKAS accredited.
NPL's bespoke primary standard reciprocity calibration facility covers a frequency range of 63 Hz to 10 kHz for IEC type LS1 microphones and from 63 Hz to 20 kHz for IEC type LS2 microphones, with a best measurement uncertainty of 0.03 dB. Phase response and low frequency calibration are also in development and should be available shortly.
Measurements are traceable to reference electrical quantities such as volts and ohms, and to length, mass and time derived elsewhere at NPL. An NPL Certificate of Calibration will be issued giving the pressure sensitivity in one-third octave bands, enabling traceability to UK national standards to be demonstrated. Re-calibration at yearly intervals is recommended to maintain this traceability. All testing at the National Physical Laboratory is underpinned by the requirements of ISO 9000, in which calibration and traceability feature prominently.
A Complete Service
The specification and calibration of measurement microphones is covered in IEC Standard 61094. NPL plays an active role in the development of this series of standards and offers a complete range of calibration services to satisfy the needs of product testing, research and development and manufacturing. For a full list of calibration services offered for measurement microphones, as well as details of other sound-in-air related services, see the Acoustics In Air Measurement Services page, or make an enquiry using the details below.
Contact
Customer Services tel: +44 20 8943 8631
E-mail: acoustics_enquiries@npl.co.uk