GRAS 40HH 1/2'' Lownoise Microphone System

Freq range: 10 Hz to 16 kHz
Dyn range: 6.5 dB(A) to 113 dB
Sensitivity: 800 mV/Pa

Technology

Typical applications and use

  • Very Low Sound pressure measurements
  • Low noise product measurements
  • Sound power measurements at low sound pressure levels
  • Measurements on hard-disk drives, computerproducts, quiet rooms etc.

The 40HH comprises:

The preamplifier and microphone are an individually matched combination. To complete the system, a special single or 10-channel power module is required and is available, i.e. GRAS 12HF for single-channel measurements or GRAS 12HM for multi-channel measurements.

The chosen power module provides all necessary voltages for powering the preamplifier(s) as well as polarizing the microphone(s).

Preamplifier

The GRAS 26HH Preamplifier has a built-in overload indicator (which is repeated on the chosen power supply) and a frequency correction facility for both pressure-microphone operation as well as free field microphone operation.

Microphone

The GRAS 40AH Microphone is an externally polarized 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 generation.

Frequency Response and Noise Floor

The chosen power supply has a two-position switch for selecting which microphone operation to use, i.e.pressure or free-field. A typical free-field response for an angle of incidence of 0° is shown in the data sheet when GRAS 40HH is switched to free-field operation. Also shown is a complete low-noise measuring system, a typical noise floor in 1/3-octave bands for both the linear and A-weighted cases.

Specifications

Frequency range (±1 dB)
Hz
12.5 to 10k
Frequency range (±2 dB)
Hz
10 to 16k
Frequency range (±3 dB)
Hz
6 to 20k
Dynamic range lower limit (microphone thermal noise)
dB(A)
6.5
Dynamic range upper limit
dB
113
Set sensitivity @ 250 Hz (±2 dB)
mV/Pa
800
Polarization voltage
V
200 V / Traditional
Microphone venting
Rear
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
CE/RoHS compliant/WEEE registered
Yes/Yes/Yes


Typical frequency response


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

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

Ordering info

Included items

GRAS 40AH

High sensitive 1/2" microphone

GRAS 26HH

Lownoise 1/2" preamplifier

Optional items

GRAS 12HF

1-Channel Power Module for Lownoise Systems

GRAS 12HM

10-Channel Power Module for Lownoise Systems

GRAS AM0363

Windscreen for 1" Microphones

GRAS 42AA

Pistonphone, Class 1

GRAS RA0090

Pistonphone Coupler

GRAS AL0006

Tripod

GRAS RA0093

Adjustable, high quality, stainless steel tripod adapter

GRAS RA0095

Dehumidifier for 1” microphones

GRAS AA0046

3 m LEMO 7-pin - LEMO 7-pin Cable for Low-noise measuring system

GRAS AA0047

10 m LEMO 7-pin - LEMO 7-pin Cable for Low-noise measuring system

GRAS AA0053-CL

Customized length LEMO 7-pin - LEMO 7-pin Cable for Low-noise measuring system

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

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