GRAS 67AX ø400 mm CCP Ground Array Microphone Kit

Freq range: 3.15 Hz to 20 kHz
Dyn range: 22 dB(A) to 150 dB
Sensitivity: 12.5 mV/Pa

Technology

Typical applications and use

  • Ground array measurements
  • General noise measurements
  • Ideal for the aerospace industry

Design

The 67AX is a ground array microphone kit designed for the aerospace industry, i.e. for measurement of noise from overhead aircraft.

The microphone set is designed to sit asymmetrically in the mounting to attain a more uniform frequency response for measurements.

The GRAS 47AX microphone is a IEC 61094 1/2'' CCP Flush-mount Microphone Set with a dynamic range from 22 dB to 150 dB and a frequency range from 3.15 Hz to 20 kHz. Its height of only 8 mm (to the diaphragm) is the ideal match for the design of the 67AX. The built-in preamplifier is a low noise constant current power (CCP) type, with a built-in TEDS circuit for automatic transducer identification.

Specifications

Frequency range (±1 dB)
Hz
5 to 12.5 k
Frequency range (±2 dB)
Hz
3.15 to 20 k
Dynamic range lower limit (microphone thermal noise)
dB(A)
22
Dynamic range upper limit
dB
150
Dynamic range upper limit with GRAS CCP preamplifier
dB
149
Set sensitivity @ 250 Hz (±2 dB)
mV/Pa
12.5
Microphone venting
Rear
Output impedance
Ω
<50
Temperature range, operation
°C / °F
-30 to 70 / -22 to 158
Temperature range, storage
°C / °F
-40 to 85 / -40 to 185
Static pressure coefficient @250 Hz
dB/kPa
-0.008
Humidity range non condensing
% RH
1 to 100
Humidity coefficient @250 Hz
dB/% RH
< 0.1
Influence of axial vibration @1 m/s²
dB re 20 µPa
66
TEDS UTID (IEEE 1451.4)
27 v. 1.0
Connector type
BNC
CE/RoHS compliant/WEEE registered
Yes/Yes/Yes
Weight
g / oz
15 / 0.529
Specification Conditions

Placement of the microphone in the plate with the windscreen on top. The cutaway of section A to A shows how the microphone fits into the plate.

GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.

Ordering info

Included items

GRAS 47AX-S1 1/2'' CCP Flush-mounted Microphone Set
GRAS GR1425 Ground plate Ø400 mm
GRAS AM0375 Windscreen for 67AX
GRAS AA0097 3 m Microdot Angled - BNC cable

Optional accessories

GRAS 42AP Intelligent Pistonphone, Class 0
GRAS RA0216 Pistonphone field-verification adapter
GRAS RA0221 Pistonphone calibration adapter

GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.

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