4
LI0171 – 18 February 2015
Introduction
The G.R.A.S. 41AC-4 Outdoor Microphone for Community & Airport Noise is a precision micro-
phone set (IEC 61672-1) for monitoring community noise and the noise of overhead aircraft.
It can be used for monitoring of noise with 90 degrees of incidence, typically community noise.
With the proper correction data, it can be used for 0 degrees of incidence, typically noise from
overhead aircraft. A USB flash drive with correction data is part of the delivery.
It is waterproof, rated at IP-55, and can operate unattended over a wide range of weather condi-
tions and temperatures for a very long period, i.e. a year or longer.
It uses a G.R.A.S. 40AE-S2 1/2” Prepolarized Free-field Microphone, High Sensitivity and a
G.R.A.S. 26AK 1/2’’ Standard Preamplifier with LEMO Connector. It is designed for use with a
Sound Level Meter with LEMO connector and power supply, and 0 V polarization voltage.
Important.
The 40AE-S2 microphone and its protective grid have been modified for the 41AC-4.
Therefore, microphone and grid cannot be replaced by standard items.
Delivered Items
1/2" Prepolarized Free-Field Microphone, High Sensitivity
40AE-S2
1/2’’ Standard Preamplifier with Integrated LEMO Connector
26AK
O-ring for preamplifier
OR2038
USB flash drive with correction data for 0° (resolution: 1/12 octave)
Wind Screen
AM0378
Release Tube (for LEMO connector)
GR1794
Top cone
-
Upper housing
-
Lower housing
-
1” pole mount adapter
RA0286
Tripod Adapter
GR1096
Tripod thread adapter
SK0017
