GRAS 40HL 1/2'' LEMO Low-noise Microphone System

Freq range: 10 Hz to 16 kHz
Dyn range: 6.5 dB(A) to 110 dB
Sensitivity: 850 mV/Pa

Technology

Typical applications and use

  • Measurements at very low sound pressurelevels
  • Measurements on hard-disk drives, computerproducts, anechoic rooms, quiet rooms, etc
  • Sound-power measurements at low levels

Design

The 40HL comprises a special high-sensitive 1/2" free-field measurement microphone and an integrated 1/2" low-noise preamplifier. In combination, they connect to most high-quality input modules with LEMO 1B connector.

Preamplifier

The preamplifier, a true 1/2" low-noise amplifIer with LEMO 1B connector, has a built-in compensation filter for free-field microphones.

Microphone

The 1/2" microphone is an externally-polarized free field microphone with a specially reduced inherent noise floor in order to achieve a high dynamic range and wide frequency range. Its diaphragm is specially tuned to yield high sensitivity coupled with low internal noise.

Operating Type 40HL

For holding the microphone, you can order tripods and for level calibration of you need a pistonphone and Calibration Adapter attenuating the pistonphone signal to 94 dB re. 20 µPa. See the tab Ordering info.

Specifications

Frequency range (±1 dB)
Hz
12.5 to 10k
Frequency range (±2 dB)
Hz
10 to 16 k
Frequency range (±3 dB)
Hz
6 to 20k
Dynamic range lower limit (microphone thermal noise)
dB(A)
6.5
Dynamic range upper limit
dB
110
Set sensitivity @ 250 Hz (±2 dB)
mV/Pa
850
Polarization voltage
V
200 V / Traditional
Microphone venting
Rear
IEC 61094-4 Compliance
WS2F
Output impedance
Ω
47
Temperature range, operation
°C / °F
–20 to 60 / -4 to 140
Temperature range, storage
°C / °F
-40 to 85 / -40 to 185
Temperature coefficient @250 Hz
dB/°C / dB/°F
-0,007 / -0,004
Static pressure coefficient @250 Hz
dB/kPa
-0.01
Humidity range non condensing
% RH
0 to 95
Humidity coefficient @250 Hz
dB/% RH
0,001
Influence of axial vibration @1 m/s²
dB re 20 µPa
63
Connector type
7-pin LEMO (FGG.1B.307)
CE/RoHS compliant/WEEE registered
Yes / Yes / Yes
Specification Conditions

Typical frequency response

Typical noise floor shown in 1/3-octave bands - linear and A-weighted

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

Ordering info

 

Optional items

GRAS AA0008

3 m LEMO-to-LEMO cable

GRAS AA0009

10 m LEMO-to-LEMO cable

GRAS AA0020-CL

Customized length LEMO 7-pin - LEMO 7-pin Cable

GRAS 12AD

1-Channel Power Module

GRAS 12AR

2-Channel Power Module

GRAS 12AA

2-Channel LEMO Power Module with gain, filters and Syscheck generator

GRAS 12AK

1-Channel Power Module with gain, filters and SysCheck generator

GRAS 12AQ

2-Channel Universal Power Module with signal conditioning and PC interface

GRAS AL0006

Tripod

GRAS RA0093

Adjustable, high quality, stainless steel tripod adapter

GRAS AM0069

Windscreen for 1/2" Microphones

GRAS 42AP

Intelligent Pistonphone, Class 0

GRAS 42AA

Pistonphone, Class 1

GRAS RA0090

94 dB Pistonphone Coupler

The cables also function as connection cables (to connect 40HL to a power module).

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

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