September 1, 2010 - Meggitt Sensing Systems announced the Endevco model EM42AA pistonphone, a battery operated handheld precision acoustic calibrator, designed to serve as a highly stable sound source for accurate and reliable calibrations of measurement microphones, sound level meters and other acoustic equipment.Designed to be directly compatible with both Endevco and other industry 1/8-inch, ¼-inch and ½-inch measurement microphones, the Endevco model EM42AA pistonphone offers a sound pressure calibration level of 114 dB re. 20 μPa, at a frequency of 250 Hz ±0.5%. To use the pistonphone, simply fit the microphone into the coupler and switch on, enabling the device to produce a constant sound pressure level on the microphone diaphragm.
The Endevco model EM42AA is most routinely used for calibrating ½-inch microphones and can be delivered with a 1-inch microphone calibration coupler, if preferred. Adapters are also included for calibrating ¼-inch and 1/8-inch microphones. Each pistonphone is factory calibrated with an accuracy of ±0.08 dB re. 20 μPa and supplied with an individual calibration certificate stating exact value and test conditions.
To further ensure reliable performance, the Endevco model EM42AA has a dual-color LED above the ON/OFF switch to indicate both battery condition and operational stability. When the pistonphone is operating properly, the LED shows green, indicating that cam speed is correctly locked at 250 Hz. If the LED displays as red during pistonphone operation, speed is incorrect, most likely because of low batteries.Because of its high stability and ability to retain precision accuracy, even under hostile environmental conditions, the Endevco model EM42AA can be used as either a laboratory standard sound source, or as field calibrator for end-to-end system checks of complete acoustic measurement systems.
