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
The GRAS 40HL 1/2" Low-noise Microphone System measures sound pressure levels down close to the threshold of human hearing. It is thus generally suitable for sound-power measurements on even very quiet products. Its very wide dynamic range permits measurements down to 6.5 dB re. 20 μPa (in 1/3-octave bands) from 20 Hz to 20 kHz.
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.
It complies with IEC 61672 class 1.
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.
TEDS
The preamplifier of the 40HL has TEDS according to IEEE 1451.4. If your measurement platform supports TEDS you can read and write data like properties and calibration data.
Operating 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
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 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 |
|
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.
