Pistonphone calibrator
114 dB, 250 - 251.2 Hz | 42AP G.R.A.S. Sound & Vibration

Click to enlarge The G.R.A.S. Pistonphone Type 42AP is a battery-operated, precision sound source for accurate and reliable calibration of measurement microphones, sound level meters and other sound measuring equipment.

It has a built-in precision barometer and a thermometer. Via its display and RS-232 interface, the user can read the actual corrected sound pressure level, as well as the calibration temperature and ambient static pressure.

With a microphone placed in the coupler of the pistonphone, the calibration level and frequency is:

* nominally 114dB re. 20µPa at either 250Hz or 251.2Hz

The actual sound pressure level, corrected for static ambient pressure, is shown on the display of the Pistonphone. The display can also show the A-weighted sound pressure level after correcting it for using an A-weighting filter.

An individual calibration chart is delivered with each Pistonphone.

The Display can be switched to show any of the following:

* Actual corrected sound pressure level in decibels
* Actual corrected sound pressure level in decibels if measured with an A-weighting filter
* Static air pressure in hPa
* Calibration temperature in ºC
* Calibration temperature in in ºF

The frequency of the pistonphone can be programmed, via its RS-232 interface, to be either 250Hz or 251.2Hz.

The Type 42AP is an extremely stable laboratory standard sound source which can also be used for field calibrations - it retains its high accuracy even under hostile environmental conditions.

The Type 42AP complies with all the requirements of IEC Standard 60942 (2003) LS.