Outdoor Microphone System - Page 7
G.R.A.S. Sound & Vibration
2.
Main Components
The following is a brief description of the main components of the Outdoor Microphone System
(see also Fig. 2.1).
All external metal parts are made of stainless steel.
Windscreen and windscreen holder with anti-bird spikes.
Electrostatic actuator housing mounted on top of the condenser microphone.
Condenser microphone and preamplifier mounted on top of the casing. The microphone
and electrostatic-actuator assembly are galvanically isolated from the system casing.
The top of the casing has an inspection window for viewing the state of the dehumidifier
when the cover screw is removed.
The cylindrical casing contains the assembly of electronics and desiccator bags for absorb
-
ing moisture.
The electronics include:
A switch-mode power supply for generating:
a)
200 V for microphone polarisation
b)
120 V for the microphone preamplifier
And:
c)
an A-weighting network
d)
a circuit jumper for applying a gain of ± 20 dB to the microphone signal
A pole adaptor with a standard ISO 228/1 G 1½-in thread. Also used for the tripod adaptor
(Fig. 2.2).
The Outdoor Microphone System can be mounted on the tripod adaptor using the pole
adaptor. The cable and plug are readily led through the tripod adaptor. The tripod adaptor
is not meant for permanent outdoor installations, but for test setups in labs and short-term
outdoor surveys.
The connector is a 6-pole LEMO FFA.2S.306, which locks into a socket at the bottom of
the Outdoor Microphone System. It cannot be pulled out by its cable. It can be removed
only by pulling outwards on the knurled outer sleeve.
