Type 41AO


Type 41AO
The G.R.A.S. Environmental Microphone System Type 41AO is a precision microphone unit (IEC 61672) for monitoring the noise of overhead aircraft. It can withstand rain and operate over a wide range of temperatures over periods lasting from a few days to several weeks.
Available Versions
With an externally-polarized Free-field Microphone Type 40AF and Preamplifier Type 26AK. Alternatively, Preamplifier Type 26AJ, with a SysCheck* feature, is available. By applying a SysCheck signal to pin 1 of the preamplifier, the response of the system will reveal any drift in sensitivity.
Type 41AO-S
With a prepolarized Free-field Microphone Type 40AE and CCP Preamplifier Type 26CA.
In both cases the reference direction for measurements is along the axis of symmetry - (i.e. 0° angle of incidence) for measurements according to IEC 61672, typically aircraft-noise monitoring.
Simple field calibration
All that is required is unscrewing the windscreen and mounting a pistonphone/calibrator directly onto the exposed microphone.
Desiccator unit
A desiccator unit (AL0014) is available if the Type 41AO is to be placed outdoors for extended periods. It screws directly onto the base of the Type 41AO and removes moisture from the air entering the unit.
Specifications Type 41AO/41AO-S
Specifications Type 41AO/41AO-S
Sensitivity: 50 mV/Pa (nominal)
Dynamic range: 14 dBA - 146 dB re. 20µPa (41AO)
14 dBA - 135 dB re. 20µPa (41AO-S)
Frequency response: IEC 61672-1 for 0° angle of incidence
Power supply (41AO): Single; 28 V to 120 V
Dual; ±14 V (0,7 mA) to ±60 V (2.3 mA)
Power supply (41AO-S): 2 mA to 20 mA
Polarisation voltage: 200 V (41AO)
0 V (41AO-S)
Output connector: 7-pin LEMO 1B, 3 m cable included (41AO)
BNC, 3 m cable included (41AO-S)
Dimensions: casing (ext. dia.) 22 mm
length 325 mm
Weight: 320 g
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