Sound and Vibration Instrument Hire and Calibration

GRAS Sound Level Calibrators

GRAS 42AA : Pistonphone Calibrator - class 1	£ 6 a day *

Battery operated for field checks of complete systems.
Laboratory calibration of measurements microphones
114 dB at 250 Hz or 105.4 dBA.
For use with 1/2" and 1/4" microphones, includes a barometer with correction values.
Certification traceable to NPL.
GRAS 42 Manufacturer's Specifications

GRAS 51AB : Sound Intensity Calibrator	£ 8 a day *

For phase and level calibration of both 1/2" and 1/4" Sound Intensity microphone pairs. The 51AB may be used for residual intensity testing, level and the particle velocity calibration as specified in BS EN 61043.
The calibrator consists of a sound source which supplies a well defined sound pressure field simultaneously to both measurement microphones, so the resulting phase difference can be expressed as the Pressure Intensity Index.
For sound intensity and particle velocity calibration a phase shifting element is inserted between the source and the receiving part of the calibrator, resulting in a phase shift similar to that found in a free field.
GRAS 51AB Manufacturer's Specifications
Needs an external generator producing white, pink or sine waves via a BNC connector, which is included in the Nor 840 analyser.
* Our standard hire charges are based on a 4-day minimum period, details other options.